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Nguetsa GC, Elanga-Ndille E, Essangui Same EG, Nganso Keptchouang T, Mandeng SE, Ekoko Eyisap W, Binyang JA, Fogang B, Nouage L, Piameu M, Ayong L, Etang J, Wanji S, Eboumbou Moukoko CE. Utility of plasma anti-gSG6-P1 IgG levels in determining changes in Anopheles gambiae bite rates in a rural area of Cameroon. Sci Rep 2024; 14:14294. [PMID: 38906949 PMCID: PMC11192751 DOI: 10.1038/s41598-024-58337-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 03/27/2024] [Indexed: 06/23/2024] Open
Abstract
The applicability of the specific human IgG antibody response to Anopheles gambiae salivary Gland Protein-6 peptide 1 (gSG6-P1 salivary peptide) as a biomarker able to distinguish the level of exposure to mosquito bites according to seasonal variations has not yet been evaluated in Central African regions. The study aimed to provide the first reliable data on the IgG anti-gSG6-P1 response in rural area in Cameroon according to the dry- and rainy-season. Between May and December 2020, dry blood samples were collected from people living in the Bankeng village in the forest area of the Centre region of Cameroon. Malaria infection was determined by thick-blood smear microscopy and multiplex PCR. The level of IgG anti-gSG6-P1 response, was assessed by enzyme-linked immunosorbent assay. Anopheles density and aggressiveness were assessed using human landing catches. The prevalence of malaria infection remains significantly higher in the rainy season than in the dry season (77.57% vs 61.44%; p = 0.0001). The specific anti-gSG6-P1 IgG response could be detected in individuals exposed to few mosquito bites and showed inter-individual heterogeneity even when living in the same exposure area. In both seasons, the level of anti-gSG6-P1 IgG response was not significantly different between Plasmodium infected and non-infected individuals. Mosquito bites were more aggressive in the rainy season compared to the dry season (human biting rate-HBR of 15.05 b/p/n vs 1.5 b/p/n) where mosquito density was very low. Infected mosquitoes were found only during the rainy season (sporozoite rate = 10.63% and entomological inoculation rate-EIR = 1.42 ib/p/n). The level of IgG anti-gSG6-P1 response was significantly higher in the rainy season and correlated with HBR (p ˂ 0.0001). This study highlights the high heterogeneity of individual's exposure to the Anopheles gambiae s.l vector bites depending on the transmission season in the same area. These findings reinforce the usefulness of the anti-gSG6-P1 IgG response as an accurate immunological biomarker for detecting individual exposure to Anopheles gambiae s.l. bites during the low risk period of malaria transmission in rural areas and for the differentiating the level of exposure to mosquitoes.
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Affiliation(s)
- Glwadys Cheteug Nguetsa
- Malaria Research Unit, Centre Pasteur Cameroon, P.O. Box 1274, Yaoundé, Cameroon.
- Department of Microbiology and Parasitology, Faculty of Sciences, The University of Buea, P.O. Box 63, Buea, Cameroon.
| | - Emmanuel Elanga-Ndille
- Department of Animal Biology, Faculty of Sciences, The University of Dschang, P.O. Box 96, Dschang, Cameroon
- Department of Medical Entomology, Centre for Research in Infectious Diseases, P.O. Box 13591, Yaoundé, Cameroon
| | - Estelle Géraldine Essangui Same
- Malaria Research Unit, Centre Pasteur Cameroon, P.O. Box 1274, Yaoundé, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, The University of Douala, P.O. Box 2701, Douala, Cameroon
| | - Tatiana Nganso Keptchouang
- Malaria Research Unit, Centre Pasteur Cameroon, P.O. Box 1274, Yaoundé, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, The University of Douala, P.O. Box 2701, Douala, Cameroon
| | - Stanilas Elysée Mandeng
- Department of Animal Biology and Physiology, Faculty of Sciences, The University of Yaoundé, P.O. Box 337, Yaounde 1, Cameroon
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
| | - Wolfgang Ekoko Eyisap
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
| | - Jérome Achille Binyang
- Department of Medical Entomology, Centre for Research in Infectious Diseases, P.O. Box 13591, Yaoundé, Cameroon
- Department of Animal Biology and Physiology, Faculty of Sciences, The University of Yaoundé, P.O. Box 337, Yaounde 1, Cameroon
| | - Balotin Fogang
- Malaria Research Unit, Centre Pasteur Cameroon, P.O. Box 1274, Yaoundé, Cameroon
- Department of Animal Biology and Physiology, Faculty of Sciences, The University of Yaoundé, P.O. Box 337, Yaounde 1, Cameroon
| | - Lynda Nouage
- Department of Medical Entomology, Centre for Research in Infectious Diseases, P.O. Box 13591, Yaoundé, Cameroon
- Department of Animal Biology and Physiology, Faculty of Sciences, The University of Yaoundé, P.O. Box 337, Yaounde 1, Cameroon
| | - Micheal Piameu
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
- Ecole des Sciences de La Santé, Université Catholique d'Afrique Centrale, P.O. Box 1110, Yaoundé, Cameroon
| | - Lawrence Ayong
- Malaria Research Unit, Centre Pasteur Cameroon, P.O. Box 1274, Yaoundé, Cameroon
| | - Josiane Etang
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, The University of Douala, P.O. Box 2701, Douala, Cameroon
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
| | - Samuel Wanji
- Department of Microbiology and Parasitology, Faculty of Sciences, The University of Buea, P.O. Box 63, Buea, Cameroon
| | - Carole Else Eboumbou Moukoko
- Malaria Research Unit, Centre Pasteur Cameroon, P.O. Box 1274, Yaoundé, Cameroon.
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, The University of Douala, P.O. Box 2701, Douala, Cameroon.
- Laboratory of Parasitology, Mycology and Virology, Postgraduate Training Unit for Health Sciences, Postgraduate School for Pure and Applied Sciences, The University of Douala, P.O. Box 2701, Douala, Cameroon.
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Belay AK, Asale A, Sole CL, Kinya F, Yusuf AA, Torto B, Mutero CM, Tchouassi DP. Vectorial drivers of malaria transmission in Jabi Tehnan district, Amhara Regional State, Ethiopia. Sci Rep 2024; 14:13669. [PMID: 38871839 PMCID: PMC11176308 DOI: 10.1038/s41598-024-64436-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Accepted: 06/10/2024] [Indexed: 06/15/2024] Open
Abstract
Among the factors affecting the effectiveness of malaria control is poor knowledge of the entomologic drivers of the disease. We investigated anopheline populations as part of a baseline study to implement house screening of windows and doors as a supplementary malaria control tool towards elimination in Jabi Tehnan district, Amhara Regional State of Ethiopia. The samples were surveyed monthly using CDC light traps between June 2020 and May 2021. Mosquito trap density (< 3 mosquitoes/trap) was low, however, with a high overall Plasmodium sporozoite rate (9%; indoor = 4.3%, outdoor = 13.1%) comprising P. falciparum (88.9%) and P. vivax (11.1%). Anopheles gambiae s.l., mostly An. arabiensis, comprised > 80% of total anopheline captures and contributed ~ 42% of Plasmodium-infected mosquitoes. On the other hand, morphologically scored Anopheles funestus s.l., constituting about 6% of anopheline collections, accounted for 50% of sporozoite-infected mosquitoes. Most of the infected An. funestus s.l. specimens (86.7%) were grouped with previously unknown or undescribed Anopheles species previously implicated as a cryptic malaria vector in the western Kenyan highlands, confirming its wider geographic distribution in eastern Africa. Other species with Plasmodium infection included An. longipalpis C, An. theileri, An. demillioni, and An. nili. Cumulatively, 77.8% of the infected mosquitoes occurred outdoors. These results suggest efficient malaria parasite transmission despite the low vector densities, which has implications for effective endpoint indicators to monitor malaria control progress. Additionally, the largely outdoor infection and discovery of previously unknown and cryptic vectors suggest an increased risk of residual malaria transmission and, thus, a constraint on effective malaria prevention and control.
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Affiliation(s)
- Aklilu K Belay
- International Centre of Insect Physiology and Ecology, P.O. Box 30772-00100, Nairobi, Kenya
- Department of Zoology and Entomology, University of Pretoria, Private Bag X0028, Pretoria, South Africa
| | - Abebe Asale
- International Centre of Insect Physiology and Ecology, P.O. Box 5689, Addis Ababa, Ethiopia
| | - Catherine L Sole
- Department of Zoology and Entomology, University of Pretoria, Private Bag X0028, Pretoria, South Africa
| | - Fiona Kinya
- International Centre of Insect Physiology and Ecology, P.O. Box 30772-00100, Nairobi, Kenya
| | - Abdullahi A Yusuf
- Department of Zoology and Entomology, University of Pretoria, Private Bag X0028, Pretoria, South Africa
| | - Baldwyn Torto
- International Centre of Insect Physiology and Ecology, P.O. Box 30772-00100, Nairobi, Kenya
- Department of Zoology and Entomology, University of Pretoria, Private Bag X0028, Pretoria, South Africa
| | - Clifford M Mutero
- International Centre of Insect Physiology and Ecology, P.O. Box 30772-00100, Nairobi, Kenya
- School of Health Systems and Public Health, University of Pretoria, Private Bag X0028, Pretoria, South Africa
| | - David P Tchouassi
- International Centre of Insect Physiology and Ecology, P.O. Box 30772-00100, Nairobi, Kenya.
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Atekem K, Nwane P, Nditanchou R, Jeyam A, Wilhelm A, Selby R, Hamill L, Schmidt E, Dixon R, Boakye D. Comparison of standard and modified human landing catching techniques for blackfly collection. Int Health 2024; 16:351-356. [PMID: 37624092 PMCID: PMC11062189 DOI: 10.1093/inthealth/ihad066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/18/2023] [Accepted: 07/26/2023] [Indexed: 08/26/2023] Open
Abstract
BACKGROUND Human landing catches (HLCs) are required to collect blackflies for entomological evaluation to verify onchocerciasis elimination. However, there are ethical concerns regarding exposure of vector collectors to infectious blackflies and safer alternative methods are needed. This study evaluated a modified HLC technique where collectors wore coloured trousers (blue, black or blue-black), protecting them from bites during fly collection, and their performance was compared with the standard. METHODS The study was conducted in Makouopsap, Cameroon, in the Massangam health district for 4 months. Four collector pairs-one 'standard' (bare-legged) and three modified-were placed 50 m apart along known breeding sites on the Mbam and Nja Rivers. Collections were performed from 07:00 to 17:00 h, 4 d/month. Hourly rates of flies caught were analysed using a negative binomial generalised linear model to explore associations between flies caught and collection techniques and seasons. RESULTS Overall, 17 246 blackflies were caught. There was no significant statistical difference in the number of blackflies and parous flies caught between black trousers and the standard. Thus there is a strong indication that wearing black trousers is a viable non-inferior alternative to the standard HLC. CONCLUSIONS Further studies are needed to confirm generalisability in different ecozones and transmission environments and among different blackfly species.
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Affiliation(s)
- Kareen Atekem
- Department of Entomology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, USA
- Sightsavers – Yaoundé, Cameroon; Haywards Heath, UK
| | - Philippe Nwane
- Centre for Research on Filariasis and Other Tropical Diseases, Yaoundé, Cameroon
- University of Yaoundé I, Cameroon
| | | | - Anita Jeyam
- Sightsavers – Yaoundé, Cameroon; Haywards Heath, UK
| | - Aude Wilhelm
- Sightsavers – Yaoundé, Cameroon; Haywards Heath, UK
| | | | | | | | - Ruth Dixon
- Sightsavers – Yaoundé, Cameroon; Haywards Heath, UK
| | - Daniel Boakye
- Parasitology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra
- End Fund, New York, NY, USA
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Kosgei J, Gimnig JE, Moshi V, Omondi S, McDermott DP, Donnelly MJ, Ouma C, Abong'o B, Ochomo E. Comparison of different trapping methods to collect malaria vectors indoors and outdoors in western Kenya. Malar J 2024; 23:81. [PMID: 38493098 PMCID: PMC10943837 DOI: 10.1186/s12936-024-04907-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 03/11/2024] [Indexed: 03/18/2024] Open
Abstract
BACKGROUND Vector surveillance is among the World Health Organization global vector control response (2017-2030) pillars. Human landing catches are a gold standard but difficult to implement and potentially expose collectors to malaria infection. Other methods like light traps, pyrethrum spray catches and aspiration are less expensive and less risky to collectors. METHODS Three mosquito sampling methods (UV light traps, CDC light traps and Prokopack aspiration) were evaluated against human landing catches (HLC) in two villages of Rarieda sub-county, Siaya County, Kenya. UV-LTs, CDC-LTs and HLCs were conducted hourly between 17:00 and 07:00. Aspiration was done indoors and outdoors between 07:00 and 11:00 a.m. Analyses of mosquito densities, species abundance and sporozoite infectivity were performed across all sampling methods. Species identification PCR and ELISAs were done for Anopheles gambiae and Anopheles funestus complexes and data analysis was done in R. RESULTS Anopheles mosquitoes sampled from 608 trapping efforts were 5,370 constituting 70.3% Anopheles funestus sensu lato (s.l.), 19.7% Anopheles coustani and 7.2% An. gambiae s.l. 93.8% of An. funestus s.l. were An. funestus sensu stricto (s.s.) and 97.8% of An. gambiae s.l. were Anopheles arabiensis. Only An. funestus were sporozoite positive with 3.1% infection prevalence. Indoors, aspiration captured higher An. funestus (mean = 6.74; RR = 8.83, P < 0.001) then UV-LT (mean = 3.70; RR = 3.97, P < 0.001) and CDC-LT (mean = 1.74; RR = 1.89, P = 0.03) compared to HLC. UV-LT and CDC-LT indoors captured averagely 0.18 An. arabiensis RR = 5.75, P = 0.028 and RR = 5.87, P = 0.028 respectively. Outdoors, UV-LT collected significantly higher Anopheles mosquitoes compared to HLC (An. funestus: RR = 5.18, P < 0.001; An. arabiensis: RR = 15.64, P = 0.009; An. coustani: RR = 11.65, P < 0.001). Anopheles funestus hourly biting indoors in UV-LT and CDC-LT indicated different peaks compared to HLC. CONCLUSIONS Anopheles funestus remains the predominant mosquito species. More mosquitoes were collected using aspiration, CDC-LTs and UV-LTs indoors and UV-LTs and CD-LTs outdoors compared to HLCs. UV-LTs collected more mosquitoes than CDC-LTs. The varied trends observed at different times of the night suggest that these methods collect mosquitoes with diverse activities and care must be taken when interpreting the results.
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Affiliation(s)
- Jackline Kosgei
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya.
- Department of Biomedical Sciences and Technology, Maseno University, Maseno, Kenya.
| | - John E Gimnig
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30333, USA
| | - Vincent Moshi
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Seline Omondi
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Daniel P McDermott
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Collins Ouma
- Department of Biomedical Sciences and Technology, Maseno University, Maseno, Kenya
| | - Bernard Abong'o
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya
| | - Eric Ochomo
- Entomology Section, Centre for Global Health Research, Kenya Medical Research Institute, P.O. Box 1578-40100, Kisumu, Kenya.
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Kampango A, Smith TA, Abílio AP, Machoe EA, Matusse JF, Pinto J, McCall PJ. The Shockwè trap: a human-baited exposure-free device for surveillance and behaviour studies of anthropophilic vectors. Wellcome Open Res 2023; 8:455. [PMID: 38644931 PMCID: PMC11031644 DOI: 10.12688/wellcomeopenres.19963.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/25/2023] [Indexed: 04/23/2024] Open
Abstract
Background: The human biting rate (MBR) and entomological inoculation rate (EIR) are common parameters routinely used to measure the risk of malaria transmission. Both parameters can be estimated using human landing catches (HLC). Although it is considered the gold-standard, HLC puts collectors at higher risk of infection with mosquito-transmitted pathogens. Methods: A novel exposure-free host-seeking mosquito electrocution trap, the Shockwè trap (SHK), was developed and its efficiency for monitoring mosquito community composition and abundance was compared with human landing catches (HLC) as the gold-standard. Field experiments were performed in Massavasse village, southern Mozambique. Simultaneous indoor and outdoor collections of nocturnal host-seeking mosquitoes were carried out using the SHK and HLC methods. The relative sampling efficiency of SHK was estimated as the ratio of the numbers of mosquitoes caught in SHK compared HLC. Proportionality and density-dependence between SHK and HLC catches were estimated by mean of Bayesian regression approaches. Results: A total of 69,758 and 27,359 host-seeking mosquitoes comprising nineteen species and four genera, were collected by HLC and SHK respectively. In general, SHK and HLC sampled similar numbers of mosquito species, with the exceptions of the least common species Aedes sudanensis, Ae. subargenteus, and Coquillettidia versicolor that were caught only by HLC. The relative sampling efficiency and proportionality between SHK and matched HLC catches varied greatly between species and collection site. However, all mosquitoes collected by SHK were unfed, confirming the Shockwè trap design's performance and reliability as a successful mosquito exposure free sampling approach. Conclusions: Results demonstrate that SHK is a safe and reliable human-exposure free device for monitoring the occurrence of a wide range of mosquito, including major malaria and arboviruses vector species. However, improvements are needed to increase its sampling efficiency for less abundant mosquito species.
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Affiliation(s)
- Ayubo Kampango
- Vectors Study Unit, Instituto Nacional de Saúde, Maputo Province, Vila de Marracuene, Mozambique
| | - Thomas A. Smith
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Ana Paula Abílio
- Vectors Study Unit, Instituto Nacional de Saúde, Maputo Province, Vila de Marracuene, Mozambique
| | - Elias Alberto Machoe
- Vectors Study Unit, Instituto Nacional de Saúde, Maputo Province, Vila de Marracuene, Mozambique
| | - Júlio Francisco Matusse
- Vectors Study Unit, Instituto Nacional de Saúde, Maputo Province, Vila de Marracuene, Mozambique
| | - João Pinto
- Global Health and Tropical Medicine, Institute of Hygiene and Tropical Medicine, Lisbon, Portugal
| | - Philip J. McCall
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
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Mbare O, Njoroge MM, Ong'wen F, Bukhari T, Fillinger U. Evaluation of the solar-powered Silver Bullet 2.1 (Lumin 8) light trap for sampling malaria vectors in western Kenya. Malar J 2023; 22:277. [PMID: 37716987 PMCID: PMC10505323 DOI: 10.1186/s12936-023-04707-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 09/07/2023] [Indexed: 09/18/2023] Open
Abstract
BACKGROUND Centers for Disease Control and Prevention (CDC) light traps are widely used for sampling mosquitoes. However, this trap, manufactured in the USA, poses challenges for use in sub-Saharan Africa due to procurement costs and shipping time. Traps that are equally efficient than the CDC light trap, but which are amenable for use in remote African settings and made in Africa, are desirable to improve local vector surveillance. This study evaluated a novel solar-powered light trap made in South Africa (Silver Bullet trap; SB), for its efficiency in malaria vector sampling in western Kenya. METHODS Large cage (173.7 m3) experiments and field evaluations were conducted to compare the CDC-incandescent light trap (CDC-iLT), CDC-UV fluorescent tube light trap (CDC-UV), SB with white diodes (SB-White) and SB with UV diodes (SB-UV) for sampling Anopheles mosquitoes. Field assessments were done indoors and outdoors following a Latin square design. The wavelengths and absolute spectral irradiance of traps were compared using spectrometry. RESULTS The odds of catching a released Anopheles in the large cage experiments with the SB-UV under ambient conditions in the presence of a CDC-iLT in the same system was three times higher than what would have been expected when the two traps were equally attractive (odds ratio (OR) 3.2, 95% confidence interval CI 2.8-3.7, P < 0.01)). However, when the white light diode was used in the SB trap, it could not compete with the CDC-iLT (OR 0.56, 95% CI 0.48-0.66, p < 0.01) when the two traps were provided as choices in a closed system. In the field, the CDC and Silver Bullet traps were equally effective in mosquito sampling. Irrespective of manufacturer, traps emitting UV light performed better than white or incandescent light for indoor sampling, collecting two times more Anopheles funestus sensu lato (s.l.) (RR 2.5; 95% CI 1.7-3.8) and Anopheles gambiae s.l. (RR 2.5; 95% 1.7-3.6). Outdoor collections were lower than indoor collections and similar for all light sources and traps. CONCLUSIONS The solar-powered SB trap compared well with the CDC trap in the field and presents a promising new surveillance device especially when charging on mains electricity is challenging in remote settings.
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Affiliation(s)
- Oscar Mbare
- International Centre of Insect Physiology and Ecology, Human Health Theme, 30772 - 00100, Nairobi, Kenya.
| | - Margaret Mendi Njoroge
- International Centre of Insect Physiology and Ecology, Human Health Theme, 30772 - 00100, Nairobi, Kenya
| | - Fedinand Ong'wen
- International Centre of Insect Physiology and Ecology, Human Health Theme, 30772 - 00100, Nairobi, Kenya
| | - Tullu Bukhari
- International Centre of Insect Physiology and Ecology, Human Health Theme, 30772 - 00100, Nairobi, Kenya
| | - Ulrike Fillinger
- International Centre of Insect Physiology and Ecology, Human Health Theme, 30772 - 00100, Nairobi, Kenya
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Costa-Neta BM, de Sousa FCDS, de Araújo EC, Viana JDC, Brito JM, Silva FS. The evening crepuscular host-seeking activity of Anopheles mosquitoes in northeast Brazil. JOURNAL OF MEDICAL ENTOMOLOGY 2023; 60:1008-1015. [PMID: 37364566 DOI: 10.1093/jme/tjad071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 05/10/2023] [Accepted: 06/09/2023] [Indexed: 06/28/2023]
Abstract
Studies on the timing of anopheline host-seeking are important for understanding mosquito ecology, behaviors, and possible role in disease transmission. To study the evening crepuscular host-seeking activity of anophelines and the effects of moonlight, anopheline mosquitoes were collected with light traps settled in a livestock area in the Brazilian Cerrado region. Traps (Silva traps) were placed next to animal enclosures at 1.5 m asl. The research was divided in 2 experiments: the first experiment (12 nights) comprised 2 trapping periods, one from 6 PM to 7 PM and one from 7 PM to 6 AM, and the second experiment (16 evenings) divided in three 20-min intervals based on the 3 twilight phases (civil: 6-6:20 PM; nautical: 6:20-6:40 PM; and astronomical: 6:40-7 PM). A total of 2,815 anopheline mosquitoes and 9 species were found. The main species were Anopheles triannulatus s.l., An. argyritarsis, An. goeldii, and An. evanse. Host-seeking mosquitoes were more frequently active during the first hour after sunset, with a significant peak in the second 20-min interval. After that, a decrease in the number of individuals was observed from the astronomical twilight onwards. Moonlight did not affect the evening flight activity of anophelines. By using LED-based passive light traps, the evening arrival time of anophelines at blood-feeding sites was demonstrated, and it may be a key time window for malaria vector control interventions.
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Affiliation(s)
- Benedita Maria Costa-Neta
- Laboratório de Entomologia Médica, Centro de Ciências de Chapadinha, Universidade Federal do Maranhão, Chapadinha, MA 65500-000, Brazil
- Programa de Pós-Graduação em Ciências da Saúde, Universidade Federal do Maranhão, CEP: 65080-805, São Luís, Maranhão, Brazil
| | - Francisca Claudia da Silva de Sousa
- Programa de Pós-Graduação em Ciência Animal, Centro de Ciências de Chapadinha, Universidade Federal do Maranhão, CEP: 65500-000, Chapadinha, MA, Brazil
| | - Eudimara Carvalho de Araújo
- Laboratório de Entomologia Médica, Centro de Ciências de Chapadinha, Universidade Federal do Maranhão, Chapadinha, MA 65500-000, Brazil
| | - Joany da Costa Viana
- Laboratório de Entomologia Médica, Centro de Ciências de Chapadinha, Universidade Federal do Maranhão, Chapadinha, MA 65500-000, Brazil
| | - Jefferson Mesquita Brito
- Laboratório de Entomologia Médica, Centro de Ciências de Chapadinha, Universidade Federal do Maranhão, Chapadinha, MA 65500-000, Brazil
| | - Francinaldo Soares Silva
- Laboratório de Entomologia Médica, Centro de Ciências de Chapadinha, Universidade Federal do Maranhão, Chapadinha, MA 65500-000, Brazil
- Programa de Pós-Graduação em Ciências da Saúde, Universidade Federal do Maranhão, CEP: 65080-805, São Luís, Maranhão, Brazil
- Programa de Pós-Graduação em Ciências Ambientais, Centro de Ciências de Chapadinha, Universidade Federal do Maranhão, CEP: 65500-000, Chapadinha, MA, Brazil
- Programa de Pós-Graduação em Biodiversidade e Conservação, Universidade Federal do Maranhão, CEP: 65080-805, São Luís, MA, Brazil
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Fletcher IK, Gibb R, Lowe R, Jones KE. Differing taxonomic responses of mosquito vectors to anthropogenic land-use change in Latin America and the Caribbean. PLoS Negl Trop Dis 2023; 17:e0011450. [PMID: 37450491 PMCID: PMC10348580 DOI: 10.1371/journal.pntd.0011450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 06/08/2023] [Indexed: 07/18/2023] Open
Abstract
Anthropogenic land-use change, such as deforestation and urban development, can affect the emergence and re-emergence of mosquito-borne diseases, e.g., dengue and malaria, by creating more favourable vector habitats. There has been a limited assessment of how mosquito vectors respond to land-use changes, including differential species responses, and the dynamic nature of these responses. Improved understanding could help design effective disease control strategies. We compiled an extensive dataset of 10,244 Aedes and Anopheles mosquito abundance records across multiple land-use types at 632 sites in Latin America and the Caribbean. Using a Bayesian mixed effects modelling framework to account for between-study differences, we compared spatial differences in the abundance and species richness of mosquitoes across multiple land-use types, including agricultural and urban areas. Overall, we found that mosquito responses to anthropogenic land-use change were highly inconsistent, with pronounced responses observed at the genus- and species levels. There were strong declines in Aedes (-26%) and Anopheles (-35%) species richness in urban areas, however certain species such as Aedes aegypti, thrived in response to anthropogenic disturbance. When abundance records were coupled with remotely sensed forest loss data, we detected a strong positive response of dominant and secondary malaria vectors to recent deforestation. This highlights the importance of the temporal dynamics of land-use change in driving disease risk and the value of large synthetic datasets for understanding changing disease risk with environmental change.
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Affiliation(s)
- Isabel K. Fletcher
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Centre on Climate Change and Planetary Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Rory Gibb
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Centre on Climate Change and Planetary Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Centre for Biodiversity and Environment Research, University College London, London, United Kingdom
| | - Rachel Lowe
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Centre on Climate Change and Planetary Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Barcelona Supercomputing Center (BSC), Barcelona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
| | - Kate E. Jones
- Centre for Biodiversity and Environment Research, University College London, London, United Kingdom
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Al-Amin HM, Rodriguez I, Phru CS, Khan WA, Haque R, Nahlen BL, Burton TA, Alam MS, Lobo NF. Composition of Anopheles species and bionomic characteristics over the peak malaria transmission season in Bandarban, Bangladesh. Malar J 2023; 22:176. [PMID: 37280591 DOI: 10.1186/s12936-023-04614-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 06/01/2023] [Indexed: 06/08/2023] Open
Abstract
BACKGROUND Joint efforts by government and non-government organizations have helped to reduce malaria in Bangladesh and set the country on a clear path to eventual malaria elimination. However, achieving that goal would be challenging without a comprehensive understanding of vector bionomics. METHODS Targeted capturing of Anopheles mosquitoes over a rainy season, utilizing specific sampling methods, including human landing catches (HLCs), CDC-light traps (CDC-LTs), and pyrethrum spray catches (PSCs) were aimed to characterize entomological drivers of transmission in four sites of Bandarban, Bangladesh. RESULTS Molecular characterization of a subset of 4637 mosquitoes has demonstrated the presence of at least 17 species whose capture rates were representative of the rainy season. Species compositions and bionomic traits did not vary between sites with Anopheles maculatus having the highest landing rate by HLCs and Anopheles vagus having the highest capture rate with CDC-LTs. Interestingly, Anopheles species compositions and capture rates varied significantly (p < 0.05) for An. vagus, between HLCs and its often-used proxy-CDC-LTs- suggesting impacts on downstream analysis. CDC-LTs capture rates demonstrated differing compositions with indoor and outdoor biting rates. For example, Anopheles nigerrimus and Anopheles nivipes were more endophagic by HLCs and more exophagic by CDC-LTs. The use of a cow-baited CDC-LT also demonstrated significantly different results when compared to a human-baited CDC-LT considering the high degree of anthropophily in these species. The exception to both zoophily and indoor resting was An. vagus, which demonstrated both anthropophily and high resting rates indoors-pointing to this species being a possible primary vector at this site. CONCLUSION A diverse Anopheles fauna in Bandarban has been confirmed through molecular methods, highlighting the potential impact of sampling techniques. Given the complexity of the local ecosystem, a better understanding of mosquito behaviour and ecology is required to achieve the goal of malaria elimination in Bangladesh.
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Affiliation(s)
- Hasan Mohammad Al-Amin
- International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh.
- Mosquito Control Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.
- School of Biological Sciences, University of Queensland, Brisbane, QLD, Australia.
| | - Isabella Rodriguez
- Eck Institute for Global Health (EIGH), University of Notre Dame, Notre Dame, IN, USA
| | - Ching Swe Phru
- International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Wasif A Khan
- International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Rashidul Haque
- International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Bernard L Nahlen
- Eck Institute for Global Health (EIGH), University of Notre Dame, Notre Dame, IN, USA
| | - Timothy A Burton
- Eck Institute for Global Health (EIGH), University of Notre Dame, Notre Dame, IN, USA
| | - Mohammad Shafiul Alam
- International Centre for Diarrhoeal Disease Research Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Neil F Lobo
- Eck Institute for Global Health (EIGH), University of Notre Dame, Notre Dame, IN, USA
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Feitoza LHM, de Carvalho LPC, da Silva LR, Meireles ACA, Rios FGF, Pessoa FAC, de Medeiros JF, Julião GR. Influence of meteorological and seasonal parameters on the activity of Culicoides paraensis (Diptera: Ceratopogonidae), an annoying anthropophilic biting midge and putative vector of Oropouche Virus in Rondônia, Brazilian Amazon. Acta Trop 2023; 243:106928. [PMID: 37088353 DOI: 10.1016/j.actatropica.2023.106928] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/15/2023] [Accepted: 04/19/2023] [Indexed: 04/25/2023]
Abstract
Biting midges of the genus Culicoides are insects of proven medical and veterinary importance, because of their role in the transmission of viruses, bacteria, protozoa and nematodes. Culicoides paraensis has been considered the main vector of the Oropouche Virus (OROV) in the urban cycle of the disease in the neotropics. Due to the great abundance of Culicoides spp. in the State of Rondônia and its epidemiological history of OROV, we investigated the biting activity in humans, the abundance as a function of meteorological parameters and seasonality, and the detection of OROV. Entomological collections occurred in three municipalities from Brazilian State of Rondônia: Porto Velho, Ariquemes, and Ouro Preto do Oeste. GLMM's were used to determine if Culicoides spp. abundance was predicted by seasonal, diurnal, and meteorological factors. Total RNA was extracted from insects and viral RNA detection was performed using the S segment as the target region of OROV via RT-qPCR. In total, 7,315 individuals were captured and identified as C. paraensis. In the dry season, 1,488 individuals (24.5%) were recorded, 4,591 (75.5%) in the rainy season, with peaks of biting activity between 4pm and 6pm. All variables showed a significative effect on the midge abundance. The rainy season, temperature between 30°C and 32°C and relative air humidity between 75% and 85% were the main predictive parameters for capturing the highest average number of insects. Our results confirm diurnal activity of C. paraensis and its greatest abundance in rainy periods. No sample was positive for the OROV, which could be explained by the virus absence in local human populations, C. paraensis as a minor vector species in the sampled localities, and probable low rate of infection of biting midges. Our findings on hourly and seasonal biting activities can provide support to intervention actions regarding vector control and surveillance of this species. This was the first study to collect and analyze biting midges in a region where human OROV cases had already been detected, but without previous information on entomovirological surveillance.
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Affiliation(s)
- Luiz Henrique Maciel Feitoza
- Fiocruz Rondônia - Fundação Oswaldo Cruz, Laboratório de Entomologia, Porto Velho, Rondônia, Brazil.; Programa de Pós-Graduação em Biologia Experimental - PGBIOEXP, Fundação Universidade Federal de Rondônia - UNIR, Porto Velho, Rondônia, Brazil..
| | - Luis Paulo Costa de Carvalho
- Fiocruz Rondônia - Fundação Oswaldo Cruz, Laboratório de Entomologia, Porto Velho, Rondônia, Brazil.; Programa de Pós-Graduação em Biologia Experimental - PGBIOEXP, Fundação Universidade Federal de Rondônia - UNIR, Porto Velho, Rondônia, Brazil
| | - Lucas Rosendo da Silva
- Fiocruz Rondônia - Fundação Oswaldo Cruz, Laboratório de Entomologia, Porto Velho, Rondônia, Brazil.; Programa de Pós-Graduação em Biologia Experimental - PGBIOEXP, Fundação Universidade Federal de Rondônia - UNIR, Porto Velho, Rondônia, Brazil
| | - Anne Caroline Alves Meireles
- Fiocruz Rondônia - Fundação Oswaldo Cruz, Laboratório de Entomologia, Porto Velho, Rondônia, Brazil.; Programa de Pós-Graduação em Biodiversidade e Saúde - Doutorado em Ciências - Instituto Oswaldo Cruz/Fiocruz Rondônia
| | - Flávia Geovana Fontineles Rios
- Fiocruz Rondônia - Fundação Oswaldo Cruz, Laboratório de Entomologia, Porto Velho, Rondônia, Brazil.; Programa de Pós-Graduação em Biologia Experimental - PGBIOEXP, Fundação Universidade Federal de Rondônia - UNIR, Porto Velho, Rondônia, Brazil
| | | | - Jansen Fernandes de Medeiros
- Fiocruz Rondônia - Fundação Oswaldo Cruz, Laboratório de Entomologia, Porto Velho, Rondônia, Brazil.; Programa de Pós-Graduação em Biologia Experimental - PGBIOEXP, Fundação Universidade Federal de Rondônia - UNIR, Porto Velho, Rondônia, Brazil.; INCT-EpiAmO Instituto Nacional de Epidemiologia da Amazônia Ocidental, Porto Velho, Rondônia, Brazil
| | - Genimar Rebouças Julião
- Fiocruz Rondônia - Fundação Oswaldo Cruz, Laboratório de Entomologia, Porto Velho, Rondônia, Brazil.; Programa de Pós-Graduação em Biologia Experimental - PGBIOEXP, Fundação Universidade Federal de Rondônia - UNIR, Porto Velho, Rondônia, Brazil.; INCT-EpiAmO Instituto Nacional de Epidemiologia da Amazônia Ocidental, Porto Velho, Rondônia, Brazil
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Mucci LF, Bergo ES, de Deus JT, Reginato SL, Pereira M, de Camargo-Neves VLF. Evaluation of Methods for Collecting Mosquitoes (Culicidae: Diptera) in Canopy and Ground Strata in the Brazilian Savanna. Trop Med Infect Dis 2022; 7:tropicalmed7120446. [PMID: 36548701 PMCID: PMC9783515 DOI: 10.3390/tropicalmed7120446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 12/08/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022] Open
Abstract
The hand-net is the standard method for capturing mosquitoes with sylvatic diurnal activity in disease outbreaks in Brazil. However, occupational risks and biases related to the collectors' abilities and attractiveness are important limitations. In this study, we compared hand-nets with automatic traps (CDC) associated to CO2 and BG-Lure® in the Vassununga State Park, a Brazilian Savanna protection area. The collections carried out over 27 days on the ground and the forest canopy. A total of 1555 mosquitoes were obtained in 20 taxa. The diversity index ranged between 1.12 and 1.79 and the dominance index from 0.22 to 0.40. The dominant species on the ground was Aedes scapularis (46.0%), and in the canopy, Hg. janthinomys/capricornii (31.9%). Haemagogus leucocelaenus was rare (n = 2). The hand-net resulted in the greatest diversity and abundance of species in both strata, followed by the traps associated with CO2. A low degree of similarity was observed between the hand-net on the ground compared to the other capture methods. The use of BG-Lure® alone resulted in a low number of specimens. In conclusion, the hand-net is still the method of choice for collecting arbovirus vectors in the diurnal period, especially yellow fever vectors.
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12
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Eckert J, Oladipupo S, Wang Y, Jiang S, Patil V, McKenzie BA, Lobo NF, Zohdy S. Which trap is best? Alternatives to outdoor human landing catches for malaria vector surveillance: a meta-analysis. Malar J 2022; 21:378. [PMID: 36494724 PMCID: PMC9733232 DOI: 10.1186/s12936-022-04332-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 10/19/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Human landing catches (HLC) are an entomological collection technique in which humans are used as attractants to capture medically relevant host-seeking mosquitoes. The use of this method has been a topic of extensive debate for decades mainly due to ethical concerns. Many alternatives to HLC have been proposed; however, no quantitative review and meta-analysis comparing HLC to outdoor alternative trapping methods has been conducted. METHODS A total of 58 comparisons across 12 countries were identified. We conducted a meta-analysis comparing the standardized mean difference of Anopheles captured by HLC and alternative traps. To explain heterogeneity, three moderators were chosen for analysis: trap type, location of study, and species captured. A meta-regression was fit to understand how the linear combination of moderators helped in explaining heterogeneity. The possibility of biased results due to publication bias was also explored. RESULTS Random-effects meta-analysis showed no statistically significant difference in the mean difference of Anopheles collected. Moderator analysis was conducted to determine the effects of trap type, geographical location of study, and the species of Anopheles captured. On average, tent-based traps captured significantly more Anopheles than outdoor HLC (95% CI: [- .9065, - 0.0544]), alternative traps in Africa captured on average more mosquitoes than outdoor HLC (95% CI: [- 2.8750, - 0.0294]), and alternative traps overall captured significantly more Anopheles gambiae s.l. than outdoor HLC (95% CI: [- 4.4613, - 0.2473]) on average. Meta-regression showed that up to 55.77% of the total heterogeneity found can be explained by a linear combination of the three moderators and the interaction between trap type and species. Subset analysis on An. gambiae s.l. showed that light traps specifically captured on average more of this species than HLC (95% CI: [- 18.3751, - 1.0629]). Publication bias likely exists. With 59.65% of studies reporting p-values less than 0.025, we believe there is an over representation in the literature of results indicating that alternative traps are superior to outdoor HLC. CONCLUSIONS Currently, there is no consensus on a single "magic bullet" alternative to outdoor HLC. The diversity of many alternative trap comparisons restricts potential metrics for comparisons to outdoor HLC. Further standardization and specific question-driven trap evaluations that consider target vector species and the vector control landscape are needed to allow for robust meta-analyses with less heterogeneity and to develop data-driven decision-making tools for malaria vector surveillance and control.
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Affiliation(s)
- Jordan Eckert
- grid.252546.20000 0001 2297 8753Department of Mathematics and Statistics, Auburn University, 221 Parker Hall, Auburn, AL 36849 USA
| | - Seun Oladipupo
- grid.252546.20000 0001 2297 8753Department of Entomology and Plant Pathology, Auburn University, Auburn, AL USA ,grid.47100.320000000419368710Molecular Biophysics and Biochemistry, Yale University, New Haven, CT USA
| | - Yifan Wang
- grid.252546.20000 0001 2297 8753Department of Entomology and Plant Pathology, Auburn University, Auburn, AL USA
| | - Shanshan Jiang
- grid.252546.20000 0001 2297 8753Department of Entomology and Plant Pathology, Auburn University, Auburn, AL USA
| | - Vivek Patil
- grid.252546.20000 0001 2297 8753Department of Biosystems Engineering, Auburn University, Auburn, AL USA
| | - Benjamin A. McKenzie
- grid.416738.f0000 0001 2163 0069Geospatial Research, Analysis and Services Program, Centers for Disease Control and Prevention, Atlanta, GA USA
| | - Neil F. Lobo
- grid.131063.60000 0001 2168 0066Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN USA
| | - Sarah Zohdy
- grid.252546.20000 0001 2297 8753College of Forestry, Wildlife, and Environment, Auburn University, Auburn, AL USA ,grid.416738.f0000 0001 2163 0069US President’s Malaria Initiative, Centers for Disease Control and Prevention, Atlanta, GA USA
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Githu V, Baravuga ME, Mbarawa A, Msuya HM, Mlacha YP, Chaki PP, Kiware S, Mirzai N, Ferguson HM, Govella NJ. Comparative evaluation of different versions of exposure-free mosquito electrocuting traps and barrier screen trap for monitoring outdoor densities and biting time phenotypes by malaria and filariasis vectors in Tanzania. Parasit Vectors 2022; 15:420. [PMID: 36369172 PMCID: PMC9652990 DOI: 10.1186/s13071-022-05549-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 10/08/2022] [Indexed: 11/13/2022] Open
Abstract
Background Estimating human exposure to mosquito vectors is crucial for the prediction of malaria transmission and intervention impact. The human landing catch method is frequently used to directly measure estimate exposure rates; however, there has been an increasing shift from this method to exposure-free alternatives, such as the mosquito electrocuting traps (MET) and other approaches. While these latter methods can provide robust and representative values of human exposure and mosquito density, they often still require a human volunteer, which poses logistical challenges. Additionally, in the case of the MET, the early MET prototype (METe) required human volunteers to wear protective clothing that could be uncomfortable. We investigated two alternative trapping approaches to address these challenges by comparing the performance of the METe prototype to: (i) a modified caged MET prototype that offers full protection to users (METc) and (ii) a barrier screen trap (BST) designed to passively sample (host-seeking and blood-fed) mosquitoes outdoors without requiring a human participant. Methods The relative performance of the METe, METc and BST were evaluated in a 3 × 3 Latin square field experiment design conducted in south-eastern Tanzania over 12 nights of sampling. The outcomes of interest were the nightly catch of mosquitoes and biting time estimates. Results The METc and BST caught similar numbers of An. arabiensis as the METe (relative ratio [RR] = 0.76, 95% confidence interval [CI]: 0.42–1.39, P = 0.38 and RR = 1.13, 95% CI: 0.63–2.04, P = 0.69, respectively). Similarly, the METc and BST caught similar numbers of Culex spp. as the METe (RR = 0.87, 95% CI: 0.62–1.22, P = 0.42 and RR = 0.80, 95% CI: 0.57–1.12, P = 0.199, respectively). All three trapping methods indicated a similar pattern of biting activity by An. arabiensis and Culex spp., characterized by biting starting in the early evening (18:00–22:00), peaking when people are typically sleeping (22:00–05:00) and dropping off drastically toward the morning (05:00–07:00). Conclusions The modifications made to the METe design to improve user comfort and remove the need for protective clothing did not result in an underestimation of mosquito vector abundance nor misrepresentation of their biting time pattern. We recommend the METc for use over the METe design. Similarly, the BST demonstrated potential for monitoring malaria and filariasis vector densities in Tanzania. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05549-4.
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Yan C, Hii J, Ngoen-Klan R, Saeung M, Chareonviriyaphap T. Semi-field evaluation of human landing catches versus human double net trap for estimating human biting rate of Anopheles minimus and Anopheles harrisoni in Thailand. PeerJ 2022; 10:e13865. [PMID: 36101880 PMCID: PMC9464434 DOI: 10.7717/peerj.13865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 07/18/2022] [Indexed: 01/24/2023] Open
Abstract
Background Whilst the human landing catch (HLC) technique is considered the 'gold standard' for estimating human-biting rates, it is labor-intensive and fraught with potential risk of exposure to infectious mosquito bites. This study evaluated the feasibility and performance of an alternative method, the human double net trap (HDNT) relative to HLC for monitoring host-seeking malaria vectors of the Anopheles minimus complex in a semi-field system (SFS). Methods HDNT and HLC were positioned in two rooms, 30 m apart at both ends of the SFS. Two human volunteers were rotated between both traps and collected released mosquitoes (n = 100) from 6:00 pm till 6:00 am. Differences in Anopheles mosquito densities among the trapping methods were compared using a generalized linear model based on a negative binomial distribution. Results There were 82.80% (2,136/2,580) of recaptures of wild-caught and 94.50% (2,835/3,000) of laboratory-reared mosquitoes that were molecularly identified as An. harrisoni and An. minimus, respectively. Mean density of An. harrisoni was significantly lower in HNDT (15.50 per night, 95% CI [12.48-18.52]) relative to HLC (25.32 per night (95% CI [22.28-28.36]), p < 0.001). Similarly, the mean density of a laboratory strain of An. minimus recaptured in HDNT was significantly lower (37.87 per night, 95% CI [34.62-41.11]) relative to HLC (56.40 per night, 95% CI [55.37-57.43]), p < 0.001. Relative sampling efficiency analysis showed that HLC was the more efficient trap in collecting the An. minimus complex in the SFS. Conclusion HDNT caught proportionately fewer An. minimus complex than HLC. HDNT was not sensitive nor significantly correlated with HLC, suggesting that it is not an alternative method to HLC.
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Affiliation(s)
- Chanly Yan
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
| | - Jeffrey Hii
- College of Public Health, Medical and Veterinary Sciences, James Cook University of North Queensland, North Queensland, Australia
| | - Ratchadawan Ngoen-Klan
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
| | - Manop Saeung
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
| | - Theeraphap Chareonviriyaphap
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand,Royal Society of Thailand, Bangkok, Thailand
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Meireles ACA, da Silva LR, Simplício MF, de Lima AA, Rios FGF, de Menezes CA, Feitoza LHM, Julião GR. Anopheline diversity in urban and peri-urban malaria foci: comparison between alternative traps and seasonal effects in a city in the Western Brazilian Amazon. Malar J 2022; 21:258. [PMID: 36068530 PMCID: PMC9450372 DOI: 10.1186/s12936-022-04274-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 08/22/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Continuous vector surveillance and sustainable interventions are mandatory in order to prevent anopheline proliferation (or spread to new areas) and interrupt malaria transmission. Anopheline abundance and richness were evaluated in urban and peri-urban malaria foci at a medium-sized city in the Brazilian Amazon, comparing the protected human landing catch technique (PHLC) and alternative sampling methods over different seasonal periods. Additional information was assessed for female feeding behaviour and faunal composition. METHODS Anophelines were sampled bimonthly in four urban and peri-urban sites in the city of Porto Velho, state of Rondônia, Brazil. The average number of captured mosquitoes was compared between an PHLC (gold standard), a tent trap (Gazetrap), and a barrier screen by means of generalized linear mixed models (GLMM), which also included season and environment (peri-urban/urban) as predictors. RESULTS Overall, 2962 Anopheles individuals belonging to 12 species and one complex were caught; Anopheles darlingi represented 86% of the individuals. More mosquitoes were captured in the peri-urban setting, and the urban setting was more diverse. The model estimates that significantly more anophelines were collected by PHLC than by the Screen method, and Gazetrap captured fewer individuals. However, the Screen technique yielded more blood-engorged females. The peak hours of biting activity were from 6 to 7 p.m. in urban areas and from 7 to 8 p.m. in peri-urban areas. CONCLUSIONS Although peri-urban settings presented a greater abundance of anophelines, Shannon and Simpson diversities were higher in urban sites. Each technique proved to be useful, depending on the purpose: PHLC was more effective in capturing the highest anopheline densities, Gazetrap caught the greatest number of species, and the barrier screen technique captured more engorged individuals. There was no seasonal effect on Anopheles assemblage structure; however, a more diverse fauna was caught in the transitional season. Biting activity was more intense from 6 to 8 p.m., with a predominance of An. darlingi.
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Affiliation(s)
- Anne Caroline Alves Meireles
- Postgraduate Program in Experimental Biology (PGBIOEXP), Federal University of Rondônia (UNIR), BR-364, Km 9.5, Porto Velho, RO, 78900-550, Brazil. .,Laboratory of Entomology, Oswaldo Cruz Foundation, FIOCRUZ Rondônia, Porto Velho, RO, 76812-245, Brazil.
| | - Lucas Rosendo da Silva
- Postgraduate Program in Experimental Biology (PGBIOEXP), Federal University of Rondônia (UNIR), BR-364, Km 9.5, Porto Velho, RO, 78900-550, Brazil.,Laboratory of Entomology, Oswaldo Cruz Foundation, FIOCRUZ Rondônia, Porto Velho, RO, 76812-245, Brazil.,INCT-EpiAmO - National Institute of Epidemiology of Western Amazônia, Porto Velho, RO, Brazil
| | - Marlon Ferreira Simplício
- Laboratory of Entomology, Oswaldo Cruz Foundation, FIOCRUZ Rondônia, Porto Velho, RO, 76812-245, Brazil
| | - Alzemar Alves de Lima
- Centro de Pesquisa em Medicina Tropical de Rondônia, CEPEM-RO, Porto Velho, RO, 76812-329, Brazil.,Centro Universitário São Lucas, Porto Velho, RO, 76805-846, Brazil
| | - Flávia Geovana Fontineles Rios
- Postgraduate Program in Experimental Biology (PGBIOEXP), Federal University of Rondônia (UNIR), BR-364, Km 9.5, Porto Velho, RO, 78900-550, Brazil.,Laboratory of Entomology, Oswaldo Cruz Foundation, FIOCRUZ Rondônia, Porto Velho, RO, 76812-245, Brazil
| | - Carla Augusta de Menezes
- Laboratory of Entomology, Oswaldo Cruz Foundation, FIOCRUZ Rondônia, Porto Velho, RO, 76812-245, Brazil
| | - Luiz Henrique Maciel Feitoza
- Postgraduate Program in Experimental Biology (PGBIOEXP), Federal University of Rondônia (UNIR), BR-364, Km 9.5, Porto Velho, RO, 78900-550, Brazil.,Laboratory of Entomology, Oswaldo Cruz Foundation, FIOCRUZ Rondônia, Porto Velho, RO, 76812-245, Brazil
| | - Genimar Rebouças Julião
- Laboratory of Entomology, Oswaldo Cruz Foundation, FIOCRUZ Rondônia, Porto Velho, RO, 76812-245, Brazil.,INCT-EpiAmO - National Institute of Epidemiology of Western Amazônia, Porto Velho, RO, Brazil
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Novianto D, Hadi UK, Soviana S, Supriyono S, Rosmanah L, Darusman HS. Diversity of mosquito species and potential arbovirus transmission in long-tailed macaque (Macaca fascicularis) breeding facilities. Vet World 2022; 15:1961-1968. [DOI: 10.14202/vetworld.2022.1961-1968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 06/29/2022] [Indexed: 11/16/2022] Open
Abstract
Background and Aim: Mosquito-borne viral infections are diseases that reduce human and animal health levels. Their transmission involves wildlife animals as reservoirs and amplifying hosts, including long-tailed macaques (Macaca fascicularis), and potentially transmits to humans and vice versa. This study aimed to determine the species diversity, richness, and biting activity of mosquitoes in a long-tailed macaque breeding area facility and discover the presence of Flavivirus and Alphavirus as the two main arboviruses reported to infect macaques.
Materials and Methods: Human landing catch, light trap, and sweep net methods were used for mosquito collection around long-tailed macaques cages at parallel times for 12 h (18:00–06:00) for 12 nights. Mosquito species were identified to the species level based on the morphological identification key for Indonesian mosquitoes. Mosquito diversity was analyzed by several diversity indices. Mosquitoes caught using the human landing catch method were pooled based on mosquito species for viral ribonucleic acid extraction. Reverse transcription-polymerase chain reaction (RT-PCR) detected the non-structural protein 5 of the Flavivirus region and the non-structural protein 4 of the Alphavirus region. This study used the man-hour density and man-biting rate formulas for mosquito density.
Results: Ten mosquito species were collected, namely, Aedes albopictus, Anopheles aconitus, Anopheles minimus, Anopheles vagus, Armigeres foliatus, Armigeres subalbatus, Culex gelidus, Culex hutchinsoni, Culex tritaeniorhynchus, and Culex quinquefasciatus. The number of mosquitoes caught using the light trap method had the highest abundance. In contrast, the number of mosquito species caught using the sweep net method had lower diversity than the other two methods. Seven mosquito species were obtained using the human landing catch method. The mosquito species with the highest density was Cx. quinquefasciatus within the observed densest period from 20:00 to 21:00. Negative results were obtained from RT-PCR testing on five species detected using universal Flavivirus and Alphavirus primers.
Conclusion: The occurrence of mosquitoes in long-tailed macaque breeding facilities can be a source of transmission of zoonotic vector-borne diseases between animals and humans and vice versa.
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Affiliation(s)
- Dimas Novianto
- Parasitology and Medical Entomology Laboratory, Animal Biomedicine Study Program, Graduate School, IPB University, Bogor, Indonesia
| | - Upik Kesumawati Hadi
- Department of Animal Infectious Diseases and Veterinary Public Health, Faculty of Veterinary Medicine, IPB University, Bogor, Indonesia
| | - Susi Soviana
- Department of Animal Infectious Diseases and Veterinary Public Health, Faculty of Veterinary Medicine, IPB University, Bogor, Indonesia
| | - Supriyono Supriyono
- Department of Animal Infectious Diseases and Veterinary Public Health, Faculty of Veterinary Medicine, IPB University, Bogor, Indonesia
| | - Lis Rosmanah
- Primate Research Centre, Institute of Research and Community Service IPB University, Bogor, Indonesia
| | - Huda Shalahudin Darusman
- Primate Research Centre, Institute of Research and Community Service IPB University, Bogor, Indonesia; Department of Anatomy, Physiology and Pharmacology, Faculty of Veterinary Medicine, IPB University, Bogor, Indonesia
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Namango IH, Marshall C, Saddler A, Ross A, Kaftan D, Tenywa F, Makungwa N, Odufuwa OG, Ligema G, Ngonyani H, Matanila I, Bharmal J, Moore J, Moore SJ, Hetzel MW. The Centres for Disease Control light trap (CDC-LT) and the human decoy trap (HDT) compared to the human landing catch (HLC) for measuring Anopheles biting in rural Tanzania. Malar J 2022; 21:181. [PMID: 35690745 PMCID: PMC9188237 DOI: 10.1186/s12936-022-04192-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 05/20/2022] [Indexed: 11/10/2022] Open
Abstract
Background Vector mosquito biting intensity is an important measure to understand malaria transmission. Human landing catch (HLC) is an effective but labour-intensive, expensive, and potentially hazardous entomological surveillance tool. The Centres for Disease Control light trap (CDC-LT) and the human decoy trap (HDT) are exposure-free alternatives. This study compared the CDC-LT and HDT against HLC for measuring Anopheles biting in rural Tanzania and assessed their suitability as HLC proxies. Methods Indoor mosquito surveys using HLC and CDC-LT and outdoor surveys using HLC and HDT were conducted in 2017 and in 2019 in Ulanga, Tanzania in 19 villages, with one trap/house/night. Species composition, sporozoite rates and density/trap/night were compared. Aggregating the data by village and month, the Bland–Altman approach was used to assess agreement between trap types. Results Overall, 66,807 Anopheles funestus and 14,606 Anopheles arabiensis adult females were caught with 6,013 CDC-LT, 339 indoor-HLC, 136 HDT and 195 outdoor-HLC collections. Indoors, CDC-LT caught fewer An. arabiensis (Adjusted rate ratio [Adj.RR] = 0.35, 95% confidence interval [CI]: 0.27–0.46, p < 0.001) and An. funestus (Adj.RR = 0.63, 95%CI: 0.51–0.79, p < 0.001) than HLC per trap/night. Outdoors, HDT caught fewer An. arabiensis (Adj.RR = 0.04, 95%CI: 0.01–0.14, p < 0.001) and An. funestus (Adj.RR = 0.10, 95%CI: 0.07–0.15, p < 0.001) than HLC. The bias and variability in number of mosquitoes caught by the different traps were dependent on mosquito densities. The relative efficacies of both CDC-LT and HDT in comparison to HLC declined with increased mosquito abundance. The variability in the ratios was substantial for low HLC counts and decreased as mosquito abundance increased. The numbers of sporozoite positive mosquitoes were low for all traps. Conclusions CDC-LT can be suitable for comparing mosquito populations between study arms or over time if accuracy in the absolute biting rate, compared to HLC, is not required. CDC-LT is useful for estimating sporozoite rates because large numbers of traps can be deployed to collect adequate mosquito samples. The present design of the HDT is not amenable for use in large-scale entomological surveys. Use of HLC remains important for estimating human exposure to mosquitoes as part of estimating the entomological inoculation rate (EIR). Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04192-9.
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Affiliation(s)
- Isaac Haggai Namango
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland. .,University of Basel, Basel, Switzerland. .,Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania.
| | - Carly Marshall
- Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania.,British Columbia Centre for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada
| | - Adam Saddler
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland.,Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania.,Telethon Kids Institute, Perth, Australia
| | - Amanda Ross
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland.,University of Basel, Basel, Switzerland
| | - David Kaftan
- Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania.,New York University Grossman School of Medicine, New York, NY, USA
| | - Frank Tenywa
- Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Noely Makungwa
- Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Olukayode G Odufuwa
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland.,University of Basel, Basel, Switzerland.,Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania.,London School of Hygiene and Tropical Medicine, London, UK
| | - Godfrey Ligema
- Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Hassan Ngonyani
- Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Isaya Matanila
- Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Jameel Bharmal
- Innovative Vector Control Consortium, Dar es Salaam, Tanzania
| | - Jason Moore
- Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Sarah J Moore
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland.,University of Basel, Basel, Switzerland.,Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania.,Nelson Mandela African Institute of Science and Technology, Arusha, Tanzania
| | - Manuel W Hetzel
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland.,University of Basel, Basel, Switzerland
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18
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Murindahabi MM, Takken W, Hakizimana E, van Vliet AJH, Poortvliet PM, Mutesa L, Koenraadt CJM. A handmade trap for malaria mosquito surveillance by citizens in Rwanda. PLoS One 2022; 17:e0266714. [PMID: 35544478 PMCID: PMC9094558 DOI: 10.1371/journal.pone.0266714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/27/2022] [Indexed: 11/18/2022] Open
Abstract
For effective sampling of mosquitoes in malaria surveillance programmes, it is essential to include attractive cues in traps. With the aim of implementing a citizen science project on malaria vectors in rural Rwanda, a handmade plastic bottle trap was designed and tested in the field to determine its effectiveness in capturing adult Anopheles gambiae sensu lato, the main malaria vector, and other mosquito species. Carbon dioxide (CO2) and light were used as attractive cues. CO2 was produced by inoculating sugar with yeast and water. Light was emitted from a torch by light-emitting diodes (LEDs). Under field conditions in rural Rwanda, three handmade trap designs were compared to Centers for Disease Control and Prevention miniature light traps (CDC-LT) in houses. The trap baited with yeast produced CO2 and light caught the highest number of mosquitoes compared to the traps baited with light alone or CO2 alone. The number of An. gambiae s.l. in the handmade trap with light and CO2 was approximately 9–10% of the number caught with a CDC light trap. This suggests that about 10 volunteers with a handmade trap could capture a similar-sized sample of An. gambiae as one CDC-LT would collect. Based on these findings, the handmade plastic bottle trap baited with sugar fermenting yeast and light represents an option for inclusion in mosquito surveillance activities in a citizen science context.
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Affiliation(s)
- Marilyn M. Murindahabi
- Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands
- College of Sciences and Technology, University of Rwanda, Kigali, Rwanda
| | - Willem Takken
- Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands
| | - Emmanuel Hakizimana
- Malaria and other Parasitic Diseases Division, Rwanda Biomedical Center, Kigali, Rwanda
| | - Arnold J. H. van Vliet
- Environmental Systems Analysis Group, Wageningen University & Research, Wageningen, The Netherlands
| | - P. Marijn Poortvliet
- Strategic Communication group, Wageningen University & Research, Wageningen, The Netherlands
| | - Leon Mutesa
- College of Medicine and Health Sciences, University of Rwanda, Kigali, Rwanda
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19
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Bertola M, Fornasiero D, Sgubin S, Mazzon L, Pombi M, Montarsi F. Comparative efficacy of BG-Sentinel 2 and CDC-like mosquito traps for monitoring potential malaria vectors in Europe. Parasit Vectors 2022; 15:160. [PMID: 35526068 PMCID: PMC9077833 DOI: 10.1186/s13071-022-05285-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 04/11/2022] [Indexed: 11/10/2022] Open
Abstract
Background Different trapping devices and attractants are used in the mosquito surveillance programs currently running in Europe. Most of these devices target vector species belonging to the genera Culex or Aedes, and no studies have yet evaluated the effectiveness of different trapping devices for the specific targeting of Anopheles mosquito species, which are potential vectors of malaria in Europe. This study aims to fill this gap in knowledge by comparing the performance of trapping methods that are commonly used in European mosquito surveillance programs for Culex and Aedes for the specific collection of adults of species of the Anopheles maculipennis complex. Methods The following combinations of traps and attractants were used: (i) BG-Sentinel 2 (BG trap) baited with a BG-Lure cartridge (BG + lure), (ii) BG trap baited with a BG-Lure cartridge and CO2 (BG + lure + CO2), (iii) Centers for Disease Control and Prevention-like trap (CDC trap) baited with CO2 (CDC + CO2), (iv) CDC trap used with light and baited with BG-Lure and CO2 (CDC light + lure + CO2). These combinations were compared in the field using a 4 × 4 Latin square study design. The trial was conducted in two sites in northeastern Italy in 2019. Anopheles species were identified morphologically and a sub-sample of An. maculipennis complex specimens were identified to species level by molecular analysis. Results Forty-eight collections were performed on 12 different trapping days at each site, and a total of 1721 An. maculipennis complex specimens were captured. The molecular analysis of a sub-sample comprising 254 specimens identified both Anopheles messeae/Anopheles daciae (n = 103) and Anopheles maculipennis sensu stricto (n = 8) at site 1, while at site 2 only An. messeae/An. daciae (n = 143) was found. The four trapping devices differed with respect to the number of An. messeae/An. daciae captured. More mosquitoes were caught by the BG trap when it was used with additional lures (i.e. BG + lure + CO2) than without the attractant, CO2 [ratioBG+lure vs BG+lure+CO2 = 0.206, 95% confidence interval (CI) 0.101–0.420, P < 0.0001], while no significant differences were observed between CDC + CO2 and CDC light + lure + CO2 (P = 0.321). The addition of CO2 to BG + lure increased the ability of this combination to capture An. messeae/An. daciae by a factor of 4.85, and it also trapped more mosquitoes of other, non-target species (Culex pipiens, ratioBG+lure vs BG+lure+CO2 = 0.119, 95% CI 0.056–0.250, P < 0.0001; Ochlerotatus caspius, ratioBG+lure vs BG+lure+CO2 = 0.035, 95% CI 0.015–0.080, P < 0.0001). Conclusions Our results show that both the BG-Sentinel and CDC trap can be used to effectively sample An. messeae/An. daciae, but that the combination of the BG-Sentinel trap with the BG-Lure and CO2 was the most effective means of achieving this. BG + lure + CO2 is considered the best combination for the routine monitoring of host-seeking An. maculipennis complex species such as An. messeae/An. daciae. The BG-Sentinel and CDC traps have value as alternative methods to human landing catches and manual aspiration for the standardized monitoring of Anopheles species in Europe. Graphical abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05285-9.
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Affiliation(s)
- Michela Bertola
- Istituto Zooprofilattico Sperimentale delle Venezie, 35020, Legnaro, Padua, Italy
| | - Diletta Fornasiero
- Istituto Zooprofilattico Sperimentale delle Venezie, 35020, Legnaro, Padua, Italy
| | - Sofia Sgubin
- Istituto Zooprofilattico Sperimentale delle Venezie, 35020, Legnaro, Padua, Italy
| | - Luca Mazzon
- Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, 35020, Legnaro, Padua, Italy
| | - Marco Pombi
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Fabrizio Montarsi
- Istituto Zooprofilattico Sperimentale delle Venezie, 35020, Legnaro, Padua, Italy. .,Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.
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20
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Jared Owiti Y. Efficacy of a simply resting box baited with crude fruit and leaf ethanol extracts of Phytolaccadodecandra (L' Herit) in capturing and killing of indoor mosquitoes (Diptera: Culicidae) at Korando, Western Kenya. Saudi J Biol Sci 2021; 28:5221-5228. [PMID: 34466100 PMCID: PMC8380997 DOI: 10.1016/j.sjbs.2021.05.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/15/2021] [Accepted: 05/18/2021] [Indexed: 11/23/2022] Open
Abstract
Effective capture and elimination of indoor resting mosquito population is important in the fight against mosquito borne diseases. This study aimed at evaluating the efficacy of a simply resting box baited with crude fruit and leaf ethanol extracts of Phytolacca dodecandra in attracting and killing indoor mosquitoes at Korando, Western Kenya. The study was conducted in three phases: pre-intervention, intervention and post intervention. Simple resting boxes made from galvanized wire frame measuring 30 cm × 30 cm × 30 cm, covered in blue and black tunic in and out and lined with carton boards were used. The boxes were baited with socks with strong human odour and 80 ml/100mls (e/w) solution of either crude ethanol fruit or leaf extracts of P. dodecandra, ethanol leaf extracts of Azadiracta indica or Deltamethrin. Deltamethrin and Azadiracta indica were used as positive and water as negative control. The treatments were applied at the intervention phase only. The boxes were left overnight in the houses and mosquitoes collected by 6.30 h. It was observed that more Culicines than Anopheline were captured irrespective of phase or treatment used. Mosquito densities reduced with phase of activity. P. dodecandra leaf extracts killed more mosquitoes than fruit or A. indica leaf extracts though the number were less than that of Deltamethrin or WHO threshold of >80% mortality. In conclusion, the simple resting boxes were effective in collecting and killing indoor mosquitoes though lethality did not matched the WHO threshold. With improved structural set up and use of pure extracts of P. dodecandra, the resting boxes can serve as effective tools for capture, elimination and management of mosquito borne diseases.
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Affiliation(s)
- Yugi Jared Owiti
- School of Science and Technology, University of Kabianga, P. O. Box 20230-20300, Kericho, Kenya
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21
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Thongsripong P, Hyman JM, Kapan DD, Bennett SN. Human-Mosquito Contact: A Missing Link in Our Understanding of Mosquito-Borne Disease Transmission Dynamics. ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA 2021; 114:397-414. [PMID: 34249219 PMCID: PMC8266639 DOI: 10.1093/aesa/saab011] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Indexed: 05/26/2023]
Abstract
Despite the critical role that contact between hosts and vectors, through vector bites, plays in driving vector-borne disease (VBD) transmission, transmission risk is primarily studied through the lens of vector density and overlooks host-vector contact dynamics. This review article synthesizes current knowledge of host-vector contact with an emphasis on mosquito bites. It provides a framework including biological and mathematical definitions of host-mosquito contact rate, blood-feeding rate, and per capita biting rates. We describe how contact rates vary and how this variation is influenced by mosquito and vertebrate factors. Our framework challenges a classic assumption that mosquitoes bite at a fixed rate determined by the duration of their gonotrophic cycle. We explore alternative ecological assumptions based on the functional response, blood index, forage ratio, and ideal free distribution within a mechanistic host-vector contact model. We highlight that host-vector contact is a critical parameter that integrates many factors driving disease transmission. A renewed focus on contact dynamics between hosts and vectors will contribute new insights into the mechanisms behind VBD spread and emergence that are sorely lacking. Given the framework for including contact rates as an explicit component of mathematical models of VBD, as well as different methods to study contact rates empirically to move the field forward, researchers should explicitly test contact rate models with empirical studies. Such integrative studies promise to enhance understanding of extrinsic and intrinsic factors affecting host-vector contact rates and thus are critical to understand both the mechanisms driving VBD emergence and guiding their prevention and control.
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Affiliation(s)
- Panpim Thongsripong
- Department of Microbiology, California Academy of Sciences, 55 Music Concourse Drive, San Francisco, CA 94118, USA
| | - James M Hyman
- Department of Mathematics, Tulane University, 6823 St. Charles Avenue, New Orleans, LA 70118, USA
| | - Durrell D Kapan
- Department of Entomology and Center for Comparative Genomics, Institute of Biodiversity Sciences and Sustainability, California Academy of Sciences, 55 Music Concourse Drive, San Francisco, CA 94118, USA
- Center for Conservation and Research Training, Pacific Biosciences Research Center, University of Hawai’i at Manoa, 3050 Maile Way, Honolulu, HI 96822
| | - Shannon N Bennett
- Department of Microbiology, California Academy of Sciences, 55 Music Concourse Drive, San Francisco, CA 94118, USA
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22
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Evaluation of Mosquito Attractant Candidates Using a High-Throughput Screening System for Aedes aegypti (L.) , Culex quinquefasciatus Say. and Anopheles minimus Theobald (Diptera: Culicidae). INSECTS 2021; 12:insects12060528. [PMID: 34204117 PMCID: PMC8226803 DOI: 10.3390/insects12060528] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/13/2021] [Accepted: 06/04/2021] [Indexed: 11/17/2022]
Abstract
Several types of olfactometers have been used to evaluate mosquito responses to agents that mimic natural volatiles that repel or attract. The Y-tube olfactometer has been widely used to study repellents and attractants, while the high-throughput screening system assay has only been used to study repellents. Whether the high-throughput screening system assay is suitable for evaluating attractants is unknown. We evaluated the responses to four lactic-acid-based mixtures and two non-lactic-acid-based chemical lure candidates using the high-throughput screening system (HITSS) for three mosquito species (laboratory strains and field populations of both Aedes aegypti (L.) and Culex quinquefasciatus Say.; laboratory strain of Anopheles minimus Theobald) under laboratory-controlled conditions. HITSS assay results showed that KU-lure #1 elicited the greatest percent attraction for pyrethroid-resistant and -susceptible Ae. aegypti. KU-lure #6 elicited the strongest attractive response for pyrethroid-susceptible and -resistant Cx. quinquefasciatus and pyrethroid-susceptible An. minimus. The response to the lures from each species was independent of the pyrethroid susceptibility status (Ae. aegypti, p = 0.825; Cx. quinquefasciatus, p = 0.056). However, a significant difference in attraction to KU-lure #6 was observed between diurnal and nocturnal mosquitoes (Cx. quinquefasciatus vs. Ae. aegypti, p = 0.014; An. minimus vs. Ae. aegypti, p = 0.001). The laboratory-level HITSS assay effectively selects potential lure candidates. Because the host-seeking behavior differs between mosquito species, further studies are needed to develop species-specific attractants. Additional studies in semi-field screen houses using commercial traps are necessary to evaluate the accuracy of these laboratory assay results.
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23
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Birungi K, Mabuka DP, Balyesima V, Namukwaya A, Chemoges EW, Kiwuwa-Muyingo S, Collins CM, Tripet F, Kayondo JK. Eave and swarm collections prove effective for biased captures of male Anopheles gambiae mosquitoes in Uganda. Parasit Vectors 2021; 14:281. [PMID: 34039430 PMCID: PMC8152359 DOI: 10.1186/s13071-021-04770-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 05/03/2021] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Traditional malaria vector sampling techniques bias collections towards female mosquitoes. Comprehensive understanding of vector dynamics requires balanced vector sampling of both males and females. Male mosquito sampling is also necessary for population size estimations by male-based mark-release-recapture (MRR) studies and for developing innovations in mosquito control, such as the male-targeted sterile insect technique and other genetic modification approaches. This study evaluated a range of collection methods which show promise in providing a more equal, or even male-biased, sex representation in the sample. RESULTS Swarms were found at all study sites and were more abundant and larger at the peak of the wet season. Swarm sampling caught the most males, but when man/hour effort was factored in, sampling of eaves by aspiration was the more efficient method and also provided a representative sample of females. Grass-roofed houses were the most productive for eave collections. Overall few mosquitoes were caught with artificial resting traps (clay pots and buckets), although these sampling methods performed better at the start of the wet season than at its peak, possibly because of changes in mosquito ecology and an increased availability of natural resting sites later in the season. Aspiration of bushes was more productive at the peak of the wet season than at the start. CONCLUSIONS The results of this study demonstrate that eave aspiration was an efficient and useful male mosquito collection method at the study sites and a potentially powerful aid for swarm location and MRR studies. The methods evaluated may together deliver more sex-balanced mosquito captures and can be used in various combinations depending on the aims and ecological parameters of a given study.
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Affiliation(s)
- Krystal Birungi
- Entomology Division, Uganda Virus Research Institute (UVRI), Plot 51-59, P.O. Box 49, Entebbe, Uganda
| | - Danspaid P. Mabuka
- Entomology Division, Uganda Virus Research Institute (UVRI), Plot 51-59, P.O. Box 49, Entebbe, Uganda
| | - Victor Balyesima
- Entomology Division, Uganda Virus Research Institute (UVRI), Plot 51-59, P.O. Box 49, Entebbe, Uganda
| | - Annet Namukwaya
- Entomology Division, Uganda Virus Research Institute (UVRI), Plot 51-59, P.O. Box 49, Entebbe, Uganda
| | - Elinor W. Chemoges
- Entomology Division, Uganda Virus Research Institute (UVRI), Plot 51-59, P.O. Box 49, Entebbe, Uganda
| | | | - C. Matilda Collins
- The Centre for Environmental Policy, Imperial College London, The Weeks Building, 16-18 Princes Gardens, London, SW7 1NE UK
| | - Frederic Tripet
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, ST5 5BG UK
| | - Jonathan K. Kayondo
- Entomology Division, Uganda Virus Research Institute (UVRI), Plot 51-59, P.O. Box 49, Entebbe, Uganda
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Keïta M, Sogoba N, Traoré B, Kané F, Coulibaly B, Traoré SF, Doumbia S. Performance of pirimiphos-methyl based Indoor Residual Spraying on entomological parameters of malaria transmission in the pyrethroid resistance region of Koulikoro, Mali. Acta Trop 2021; 216:105820. [PMID: 33400915 PMCID: PMC8008285 DOI: 10.1016/j.actatropica.2020.105820] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 12/23/2020] [Accepted: 12/24/2020] [Indexed: 11/28/2022]
Abstract
Malaria vector control in Mali relies heavily on the use of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) in selected districts. As part of strengthening vector control strategies in Koulikoro district, the National Malaria Control Programme (NMCP) through the support from the US President's Malaria Initiative (PMI) has strategically driven the implementation of IRS, with the LLINs coverage also rising from 93.3% and 98.2%. Due to the increased reports of vector resistance to both pyrethroid and carbamates, there was a campaign for the use of pirimiphos-methyl, an organophosphate at Koulikoro between 2015 and 2016. In this study, the effect of IRS on malaria transmission was assessed, by comparing some key entomological indices between Koulikoro, where IRS was implemented and its neighboring district, Banamba that has never received IRS as vector control intervention. The study was conducted in two villages of each district (Koulikoro and Banamba). Pyrethrum spray catches and entry window trapping were used to collect mosquitoes on a monthly basis. WHO tube tests were carried out to assess mosquito susceptibility to insecticides. Mosquitoes were identified to species level by PCR and their infection to P. falciparum was detected by Enzyme Linked-Immuno-Sorbent Assay (ELISA). Of the 527 specimens identified, An. coluzzii was the most frequent species (95%) followed by An. gambiae (4%) and An. arabiensis (1%). Its density was rainfall dependent in the no-IRS area, and almost independent in the IRS area. The infection rate (IR) in the no-IRS area was 0.96%, while it was null in the IRS area. In the no-IRS area, the entomological inoculation rate (EIR) was 0.21 infective bites /person month with a peak in September. High resistance to pyrethroids and carbamates and susceptibility to organophosphates was observed at all sites. The introduction of pirimiphos-methyl based IRS for vector control resulted in a significant decrease in malaria transmission. An. gambiae s.l., the main malaria vector in the area, was resistant to pyrethroids and carbamates but remained susceptible to the organophosphate pirimiphos-methyl.
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Affiliation(s)
- Moussa Keïta
- Malaria Research and Training Center/International Center for Excellence in Research (ICER-Mali)/ Faculty of Medicine and Odonto Stomatology/University of Sciences, Techniques and Technologies of Bamako (USTTB) Bamako, Mali.
| | - Nafomon Sogoba
- Malaria Research and Training Center/International Center for Excellence in Research (ICER-Mali)/ Faculty of Medicine and Odonto Stomatology/University of Sciences, Techniques and Technologies of Bamako (USTTB) Bamako, Mali
| | - Boïssé Traoré
- Malaria Research and Training Center/International Center for Excellence in Research (ICER-Mali)/ Faculty of Medicine and Odonto Stomatology/University of Sciences, Techniques and Technologies of Bamako (USTTB) Bamako, Mali
| | - Fousseyni Kané
- Malaria Research and Training Center/International Center for Excellence in Research (ICER-Mali)/ Faculty of Medicine and Odonto Stomatology/University of Sciences, Techniques and Technologies of Bamako (USTTB) Bamako, Mali
| | - Boubacar Coulibaly
- Malaria Research and Training Center/International Center for Excellence in Research (ICER-Mali)/ Faculty of Medicine and Odonto Stomatology/University of Sciences, Techniques and Technologies of Bamako (USTTB) Bamako, Mali
| | - Sekou Fantamady Traoré
- Malaria Research and Training Center/International Center for Excellence in Research (ICER-Mali)/ Faculty of Medicine and Odonto Stomatology/University of Sciences, Techniques and Technologies of Bamako (USTTB) Bamako, Mali
| | - Seydou Doumbia
- Malaria Research and Training Center/International Center for Excellence in Research (ICER-Mali)/ Faculty of Medicine and Odonto Stomatology/University of Sciences, Techniques and Technologies of Bamako (USTTB) Bamako, Mali
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Jeyaprakasam NK, Pramasivan S, Liew JWK, Van Low L, Wan-Sulaiman WY, Ngui R, Jelip J, Vythilingam I. Evaluation of Mosquito Magnet and other collection tools for Anopheles mosquito vectors of simian malaria. Parasit Vectors 2021; 14:184. [PMID: 33794965 PMCID: PMC8015311 DOI: 10.1186/s13071-021-04689-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/16/2021] [Indexed: 12/21/2022] Open
Abstract
Background Vector surveillance is essential in determining the geographical distribution of mosquito vectors and understanding the dynamics of malaria transmission. With the elimination of human malaria cases, knowlesi malaria cases in humans are increasing in Malaysia. This necessitates intensive vector studies using safer trapping methods which are both field efficient and able to attract the local vector populations. Thus, this study evaluated the potential of Mosquito Magnet as a collection tool for Anopheles mosquito vectors of simian malaria along with other known collection methods. Methods A randomized 4 × 4 Latin square designed experiment was conducted to compare the efficiency of the Mosquito Magnet against three other common trapping methods: human landing catch (HLC), CDC light trap and human baited trap (HBT). The experiment was conducted over six replicates where sampling within each replicate was carried out for 4 consecutive nights. An additional 4 nights of sampling was used to further evaluate the Mosquito Magnet against the “gold standard” HLC. The abundance of Anopheles sampled by different methods was compared and evaluated with focus on the Anopheles from the Leucosphyrus group, the vectors of knowlesi malaria. Results The Latin square designed experiment showed HLC caught the greatest number of Anopheles mosquitoes (n = 321) compared to the HBT (n = 87), Mosquito Magnet (n = 58) and CDC light trap (n = 13). The GLMM analysis showed that the HLC method caught significantly more Anopheles mosquitoes compared to Mosquito Magnet (P = 0.049). However, there was no significant difference in mean nightly catch of Anopheles mosquitoes between Mosquito Magnet and the other two trapping methods, HBT (P = 0.646) and CDC light traps (P = 0.197). The mean nightly catch for both An. introlatus (9.33 ± 4.341) and An. cracens (4.00 ± 2.273) caught using HLC was higher than that of Mosquito Magnet, though the differences were not statistically significant (P > 0.05). This is in contrast to the mean nightly catch of An. sinensis (15.75 ± 5.640) and An. maculatus (15.78 ± 3.479) where HLC showed significantly more mosquito catches compared to Mosquito Magnet (P < 0.05). Conclusions Mosquito Magnet has a promising ability to catch An. introlatus and An. cracens, the important vectors of knowlesi and other simian malarias in Peninsular Malaysia. The ability of Mosquito Magnet to catch some of the Anopheles mosquito species is comparable to HLC and makes it an ethical and safer alternative. Graphic Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-021-04689-3.
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Affiliation(s)
| | - Sandthya Pramasivan
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Jonathan Wee Kent Liew
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Lun Van Low
- Tropical Infectious Diseases Research and Education Centre (TIDREC), University of Malaya, Kuala Lumpur, Malaysia
| | - Wan-Yusoff Wan-Sulaiman
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Romano Ngui
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Jenarun Jelip
- Division of Disease Control, Ministry of Health Malaysia, Putrajaya, Malaysia
| | - Indra Vythilingam
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
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Dugassa S, Murphy M, Chibsa S, Tadesse Y, Yohannes G, Lorenz LM, Solomon H, Yewhalaw D, Irish SR. Malaria in migrant agricultural workers in western Ethiopia: entomological assessment of malaria transmission risk. Malar J 2021; 20:95. [PMID: 33593385 PMCID: PMC7885338 DOI: 10.1186/s12936-021-03633-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/04/2021] [Accepted: 02/06/2021] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Ethiopia has made great strides in malaria control over the last two decades. However, this progress has not been uniform and one concern has been reported high rates of malaria transmission in large agricultural development areas in western Ethiopia. Improved vector control is one way this transmission might be addressed, but little is known about malaria vectors in this part of the country. METHODS To better understand the vector species involved in malaria transmission and their behaviour, human landing collections were conducted in Dangur woreda, Benishangul-Gumuz, between July and December 2017. This period encompasses the months with the highest rain and the peak mosquito population. Mosquitoes were identified to species and tested for the presence of Plasmodium sporozoites. RESULTS The predominant species of the Anopheles collected was Anopheles arabiensis (1,733; i.e. 61.3 % of the entire Anopheles), which was also the only species identified with sporozoites (Plasmodium falciparum and Plasmodium vivax). Anopheles arabiensis was collected as early in the evening as 18:00 h-19:00 h, and host-seeking continued until 5:00 h-6:00 h. Nearly equal numbers were collected indoors and outdoors. The calculated entomological inoculation rate for An. arabiensis for the study period was 1.41 infectious bites per month. More An. arabiensis were collected inside and outside worker's shelters than in fields where workers were working at night. CONCLUSIONS Anopheles arabiensis is likely to be the primary vector of malaria in the agricultural development areas studied. High rates of human biting took place inside and outdoor near workers' residential housing. Improved and targeted vector control in this area might considerably reduce malaria transmission.
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Affiliation(s)
- Sisay Dugassa
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Mathew Murphy
- Centers for Disease Control and Prevention, 1600 Clifton Road, 30329-4027, Atlanta, GA, USA
- The US President's Malaria Initiative, Bureau for Global Health, United States Agency for International Development, 1300 Pennsylvania Ave NW, 20523, Washington, DC, USA
| | - Sheleme Chibsa
- The US President's Malaria Initiative, Bureau for Global Health, United States Agency for International Development, 1300 Pennsylvania Ave NW, 20523, Washington, DC, USA
- U.S. Agency for International Development (USAID), Entoto Street, Addis Ababa, Ethiopia
| | - Yehualashet Tadesse
- The President's Malaria Initiative Private Health Sector Project, Abt Associates Inc, Haile Gebreselassie road, Rebecca Building, 5th Floor, Addis Ababa, Ethiopia
| | - Gedeon Yohannes
- The President's Malaria Initiative Africa Indoor Residual Spraying Project, Abt Associates, Gerji Road, Sami Building, 1st Floor, Addis Ababa, Ethiopia
| | - Lena M Lorenz
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, WC1E 7HT, London, UK
- College of Medicine & Veterinary Medicine, University of Edinburgh, University of Edinburgh, UK
| | - Hiwot Solomon
- Disease prevention and control directorate, Federal Ministry of Health, Addis Ababa, Ethiopia
| | - Delenasaw Yewhalaw
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
- Department of Medical Laboratory Sciences and Pathology, College of Health Sciences, Jimma University, Jimma, Ethiopia
| | - Seth R Irish
- Centers for Disease Control and Prevention, 1600 Clifton Road, 30329-4027, Atlanta, GA, USA
- The US President's Malaria Initiative, Bureau for Global Health, United States Agency for International Development, 1300 Pennsylvania Ave NW, 20523, Washington, DC, USA
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Chaves LSM, Bergo ES, Conn JE, Laporta GZ, Prist PR, Sallum MAM. Anthropogenic landscape decreases mosquito biodiversity and drives malaria vector proliferation in the Amazon rainforest. PLoS One 2021; 16:e0245087. [PMID: 33444320 PMCID: PMC7808592 DOI: 10.1371/journal.pone.0245087] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/21/2020] [Indexed: 01/25/2023] Open
Abstract
Inter-relationships among mosquito vectors, Plasmodium parasites, human ecology, and biotic and abiotic factors, drive malaria risk. Specifically, rural landscapes shaped by human activities have a great potential to increase the abundance of malaria vectors, putting many vulnerable people at risk. Understanding at which point the abundance of vectors increases in the landscape can help to design policies and interventions for effective and sustainable control. Using a dataset of adult female mosquitoes collected at 79 sites in malaria endemic areas in the Brazilian Amazon, this study aimed to (1) verify the association among forest cover percentage (PLAND), forest edge density (ED), and variation in mosquito diversity; and to (2) test the hypothesis of an association between landscape structure (i.e., PLAND and ED) and Nyssorhynchus darlingi (Root) dominance. Mosquito collections were performed employing human landing catch (HLC) (peridomestic habitat) and Shannon trap combined with HLC (forest fringe habitat). Nyssorhynchus darlingi abundance was used as the response variable in a generalized linear mixed model, and the Shannon diversity index (H') of the Culicidae community, PLAND, and the distance house-water drainage were used as predictors. Three ED categories were also used as random effects. A path analysis was used to understand comparative strengths of direct and indirect relationships among Amazon vegetation classes, Culicidae community, and Ny. darlingi abundance. Our results demonstrate that Ny. darlingi is negatively affected by H´ and PLAND of peridomestic habitat, and that increasing these variables (one-unit value at β0 = 768) leads to a decrease of 226 (P < 0.001) and 533 (P = 0.003) individuals, respectively. At the forest fringe, a similar result was found for H' (β1 = -218; P < 0.001) and PLAND (β1 = -337; P = 0.04). Anthropogenic changes in the Amazon vegetation classes decreased mosquito biodiversity, leading to increased Ny. darlingi abundance. Changes in landscape structure, specifically decreases in PLAND and increases in ED, led to Ny. darlingi becoming the dominant species, increasing malaria risk. Ecological mechanisms involving changes in landscape and mosquito species composition can help to understand changes in the epidemiology of malaria.
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Affiliation(s)
| | - Eduardo Sterlino Bergo
- Superintendência de Controle de Endemias, Secretaria de Estado da Saúde de São Paulo, Araraquara, SP, Brazil
| | - Jan E. Conn
- Wadsworth Center, New York State Department of Health, Albany, NY, United States of America
- Department of Biomedical Sciences, School of Public Health, State University of New York, Albany, NY, United States of America
| | - Gabriel Zorello Laporta
- Setor de Pós-graduação, Pesquisa e Inovação, Centro Universitário Saúde ABC, Fundação ABC, Santo André, SP, Brazil
| | - Paula Ribeiro Prist
- Department of Ecology, Institute of Bioscience, University of São Paulo, São Paulo, SP, Brazil
| | - Maria Anice Mureb Sallum
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, SP, Brazil
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Mieguim Ngninpogni D, Ndo C, Ntonga Akono P, Nguemo A, Nguepi A, Metitsi DR, Tombi J, Awono-Ambene P, Bilong Bilong CF. Insights into factors sustaining persistence of high malaria transmission in forested areas of sub-Saharan Africa: the case of Mvoua, South Cameroon. Parasit Vectors 2021; 14:2. [PMID: 33388082 PMCID: PMC7778824 DOI: 10.1186/s13071-020-04525-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 12/07/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In Mvoua, a village situated in a forested area of Cameroon, recent studies have reported high prevalence of Plasmodium falciparum infection among the population. In order to understand factors that can sustain such a high malaria transmission, we investigated the biology of Anopheles vectors and its susceptibility to insecticides, as well as long-lasting insecticidal net (LLIN) coverage, use and bio-efficacy. METHODS A longitudinal entomological survey was conducted from July 2018 to April 2019. Adult mosquitoes were collected using the human landing catch (HLC) method and identified using morphological and molecular techniques. Anopheles gambiae (s.l.) larvae were sampled from several stagnant water pools throughout the village and reared to generate F1 adults. The presence of P. falciparum circumsporozoite antigen was detected in the heads and thoraces of mosquitoes collected as adults using an enzyme-linked immunosorbent assay. The insecticide susceptibility status of the local An. gambiae (s.l.) F1 population to the pyrethroid insecticides deltamethrin 0.5% and permethrin 0.75% was determined using World Health Organization-tube bioassays, while the frequency of the knockdown resistance (kdr) mutation was determined by PCR. Coverage, use and physical integrity of LLINs were assessed in households, then cone assays were used to test for their bio-efficacy on both the reference insecticide-susceptible Kisumu strain and on field F1 An. gambiae (s.l.) RESULTS: In total, 110 Anopheles mosquitoes were collected, of which 59.1% were identified as Anopheles funestus (s.l.), 38.18% as An. gambiae (s.l.) and 2.72% as An. ziemanii. Anopheles funestus was the most abundant species except in the long rainy season, when An. gambiae (s.l.) predominated (65.8%). In the dry seasons, vectors were principally endophagous (76% of those collected indoors) while they tended to be exophagous (66% of those collected outdoors) in rainy seasons. High Plasmodium infection was observed in An. gambiae (s.l.) and An. funestus, with a circumsporozoitic rate of 14.29 and 10.77%, respectively. Anopheles gambiae (s.l.) was highly resistant to pyrethroid insecticides (mortality rates: 32% for permethrin and 5% for deltamethrin) and harbored the kdr-L1014F mutation at a high frequency (89.74%). Of the 80 households surveyed, only 47.69% had achieved universal coverage with LLNs. Around 70% of the LLINs sampled were in poor physical condition, with a proportionate hole index > 300. Of the ten LLNs tested, eight were effective against the An. gambiae reference insecticide-susceptible Kisumu strain, showing mortality rate of > 80%, while none of these LLINs were efficient against local An. gamabie (s.l.) populations (mortality rates < 11.5%). CONCLUSION A combination of elevated P. falciparum infection in Anopheles vector populations, insufficient coverage and loss of effectiveness of LLINs due to physical degradation, as well as high resistance to pyrethroid insecticides is responsible for the persistence of high malaria transmission in forested rural area of Mvoua, Cameroon.
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Affiliation(s)
- Dominique Mieguim Ngninpogni
- Laboratory of Parasitology and Ecology, Faculty of Sciences, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
| | - Cyrille Ndo
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, P.O. Box 24157, Douala, Cameroon
- Department of Parasitology and Microbiology, Centre for Research in Infectious Diseases (CRID), P.O. Box 13591, Yaoundé, Cameroon
| | - Patrick Ntonga Akono
- Animal Organisms Laboratory, Faculty of Sciences, University of Douala, P.O. Box 24157, Douala, Cameroon
| | - Anicet Nguemo
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
- Animal Organisms Laboratory, Faculty of Sciences, University of Douala, P.O. Box 24157, Douala, Cameroon
| | - Amine Nguepi
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
- Animal Organisms Laboratory, Faculty of Sciences, University of Douala, P.O. Box 24157, Douala, Cameroon
| | - Danale Rosine Metitsi
- Laboratory of Parasitology and Ecology, Faculty of Sciences, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
| | - Jeannette Tombi
- Laboratory of Parasitology and Ecology, Faculty of Sciences, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon
| | - Parfait Awono-Ambene
- Institut de Recherche de Yaoundé (IRY), Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
| | - Charles Félix Bilong Bilong
- Laboratory of Parasitology and Ecology, Faculty of Sciences, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon
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Cheteug G, Elanga-Ndille E, Donkeu C, Ekoko W, Oloume M, Essangui E, Nwane P, NSango SE, Etang J, Wanji S, Ayong L, Eboumbou Moukoko CE. Preliminary validation of the use of IgG antibody response to Anopheles gSG6-p1 salivary peptide to assess human exposure to malaria vector bites in two endemic areas of Cameroon in Central Africa. PLoS One 2020; 15:e0242510. [PMID: 33382730 PMCID: PMC7774847 DOI: 10.1371/journal.pone.0242510] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 11/03/2020] [Indexed: 11/25/2022] Open
Abstract
The specific immune response to the Anopheles salivary peptide could be a pertinent and complementary tool to assess the risk of malaria transmission and the effectiveness of vector control strategies. This study aimed to obtain first reliable data on the current state of the Anopheles gSG6-P1 biomarker for assess the level of exposure to Anopheles bites in high malaria endemic areas in Cameroon. Blood smears were collected from people living in the neighborhoods of Youpwe (suburban area, continental) and Manoka (rural area, Island), both areas in the coastal region of Cameroon. Malaria infection was determined using thick blood smear microscopy, whereas the level of specific IgG response to gSG-P1 peptide was assessed by enzyme-linked immunosorbent assay from the dried blood spots. Of 266 (153 from Youpwe, 113 from Manoka) malaria endemic residents (mean age: 22.8±19.8 years, age range: 6 months–94 years, male/female sex ratio: 1/1.2, with Manoka mean age: 23.71±20.53, male/female sex ratio:1/1.13 and Youpwe mean age: 22.12±19.22, male/female sex ratio 1/0.67) randomly included in the study, Plasmodium infection prevalence was significantly higher in Manoka than in Youpwe (64.6% vs 12,4%, p = 0.0001). The anti-gSG6-P1 IgG response showed a high inter-individual heterogeneity and was significantly higher among individuals from Manoka than those from Youpwe (p = 0.023). Malaria infected individuals presented a higher anti-gSG6-P1 IgG antibody response than non-infected (p = 0.0004). No significant difference in the level of specific IgG response to gSG-P1 was observed according to long lasting insecticidal nets use. Taken together, the data revealed that human IgG antibody response to Anopheles gSG-P1 salivary peptide could be also used to assess human exposure to malaria vectors in Central African region. This finding strengthens the relevance of this candidate biomarker to be used for measuring human exposure to malaria vectors worldwide.
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Affiliation(s)
- Glwadys Cheteug
- Malaria Research Unit, Centre Pasteur Cameroon, Yaounde, Cameroon
- Department of Microbiology and Parasitology, Faculty of Sciences, University of Buea, Buea, Cameroon
| | | | - Christiane Donkeu
- Malaria Research Unit, Centre Pasteur Cameroon, Yaounde, Cameroon
- Department of Animal Biology and Physiology, Faculty of Sciences, University of Yaounde, Yaounde, Cameroon
| | - Wolfgang Ekoko
- Parasitology and Entomology Research Unit, Department of Animal Biology and Organisms, Faculty of Sciences, University of Douala, Douala, Cameroon
| | - Martine Oloume
- Department of hematology, Centre Pasteur of Cameroon, Yaoundé, Cameroon
| | - Estelle Essangui
- Malaria Research Unit, Centre Pasteur Cameroon, Yaounde, Cameroon
- Parasitology and Entomology Research Unit, Department of Animal Biology and Organisms, Faculty of Sciences, University of Douala, Douala, Cameroon
| | - Philippe Nwane
- Biological Sciences Department, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
| | - Sandrine Eveline NSango
- Malaria Research Unit, Centre Pasteur Cameroon, Yaounde, Cameroon
- Laboratory of Parasitology, Mycology and Virology, Postgraduate Training Unit for Health Sciences, Postgraduate School for Pure and Applied Sciences, University of Douala, Douala, Cameroon
| | - Josiane Etang
- Biological Sciences Department, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
- Organisation de Coordination pour la Lutte contre les Endemies en Afrique Central, Yaounde, Cameroon
| | - Samuel Wanji
- Department of Microbiology and Parasitology, Faculty of Sciences, University of Buea, Buea, Cameroon
| | - Lawrence Ayong
- Malaria Research Unit, Centre Pasteur Cameroon, Yaounde, Cameroon
| | - Carole Else Eboumbou Moukoko
- Malaria Research Unit, Centre Pasteur Cameroon, Yaounde, Cameroon
- Biological Sciences Department, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
- Laboratory of Parasitology, Mycology and Virology, Postgraduate Training Unit for Health Sciences, Postgraduate School for Pure and Applied Sciences, University of Douala, Douala, Cameroon
- * E-mail: ,
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Thongsripong P, Qu Z, Yukich JO, Hyman JM, Wesson DM. An Investigation of Human-Mosquito Contact Using Surveys and Its Application in Assessing Dengue Viral Transmission Risk. JOURNAL OF MEDICAL ENTOMOLOGY 2020; 57:1942-1954. [PMID: 32652036 DOI: 10.1093/jme/tjaa134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Indexed: 06/11/2023]
Abstract
Aedes-borne viral diseases such as dengue fever are surging in incidence in recent years. To investigate viral transmission risks, the availability of local transmission parameters is essential. One of the most important factors directly determining infection risk is human-mosquito contact. Yet the contact rate is not often characterized, compared with other risk metrics such as vector density, because of the limited research tool options. In this study, human-mosquito contact was assessed in two study sites in the Southern United States using self-administered standardized survey instruments. The fraction of mosquito bites attributed to important vector species was estimated by human landing sampling. The survey participants reported a significantly higher outdoor mosquito bite exposure than indoor. The reported bite number was positively correlated with outdoor time during at-risk periods. There was also a significant effect of the study site on outdoor bite exposure, possibly due to the differing vector density. Thus, the levels of human-mosquito contact in this study were influenced both by the mosquito density and human behaviors. A dengue virus transmission model demonstrated that the observed difference in the contact rates results in differential virus transmission risks. Our findings highlight the practicality of using surveys to investigate human-mosquito contact in a setting where bite exposure levels differ substantially, and serve as a basis for further evaluations. This study underscores a new avenue that can be used in combination with other field methods to understand how changes in human behavior may influence mosquito bite exposure which drives mosquito-borne virus transmission.
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Affiliation(s)
| | - Zhuolin Qu
- Department of Mathematics, Tulane University, New Orleans, LA
| | - Joshua O Yukich
- Department of Tropical Medicine, Tulane University, New Orleans, LA
| | - James M Hyman
- Department of Mathematics, Tulane University, New Orleans, LA
| | - Dawn M Wesson
- Department of Tropical Medicine, Tulane University, New Orleans, LA
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Sloyer KE, Burkett‐Cadena ND. Development and field evaluation of a motion sensor activated suction trap to study vector–host interactions. Methods Ecol Evol 2020. [DOI: 10.1111/2041-210x.13500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Kristin E. Sloyer
- Florida Medical Entomology Laboratory University of Florida IFAS Vero Beach FL USA
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Martin JA, Hendershot AL, Saá Portilla IA, English DJ, Woodruff M, Vera-Arias CA, Salazar-Costa BE, Bustillos JJ, Saénz FE, Ocaña-Mayorga S, Koepfli C, Lobo NF. Anopheline and human drivers of malaria risk in northern coastal, Ecuador: a pilot study. Malar J 2020; 19:354. [PMID: 33008438 PMCID: PMC7532652 DOI: 10.1186/s12936-020-03426-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/23/2020] [Indexed: 11/28/2022] Open
Abstract
Background Understanding local anopheline vector species and their bionomic traits, as well as related human factors, can help combat gaps in protection. Methods In San José de Chamanga, Esmeraldas, at the Ecuadorian Pacific coast, anopheline mosquitoes were sampled by both human landing collections (HLCs) and indoor-resting aspirations (IAs) and identified using both morphological and molecular methods. Human behaviour observations (HBOs) (including temporal location and bed net use) were documented during HLCs as well as through community surveys to determine exposure to mosquito bites. A cross-sectional evaluation of Plasmodium falciparum and Plasmodium vivax infections was conducted alongside a malaria questionnaire. Results Among 222 anopheline specimens captured, based on molecular analysis, 218 were Nyssorhynchus albimanus, 3 Anopheles calderoni (n = 3), and one remains unidentified. Anopheline mean human-biting rate (HBR) outdoors was (13.69), and indoors (3.38) (p = 0.006). No anophelines were documented resting on walls during IAs. HBO-adjusted human landing rates suggested that the highest risk of being bitten was outdoors between 18.00 and 20.00 h. Human behaviour-adjusted biting rates suggest that overall, long-lasting insecticidal bed nets (LLINs) only protected against 13.2% of exposure to bites, with 86.8% of exposure during the night spent outside of bed net protection. The malaria survey found 2/398 individuals positive for asymptomatic P. falciparum infections. The questionnaire reported high (73.4%) bed net use, with low knowledge of malaria. Conclusion The exophagic feeding of anopheline vectors in San Jose de Chamanga, when analysed in conjunction with human behaviour, indicates a clear gap in protection even with high LLIN coverage. The lack of indoor-resting anophelines suggests that indoor residual spraying (IRS) may have limited effect. The presence of asymptomatic infections implies the presence of a human reservoir that may maintain transmission.
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Affiliation(s)
- James A Martin
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Allison L Hendershot
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Iván Alejandro Saá Portilla
- Centro de Investigación Para La Salud en América Latina, Facultad de Ciencias Exactas Y Naturales, Pontificia Universidad Católica del Ecuador, Calle San Pedro Y Pambahacienda, 170530, Nayón, Ecuador
| | - Daniel J English
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Madeline Woodruff
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Claudia A Vera-Arias
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA.,Centro de Investigación Para La Salud en América Latina, Facultad de Ciencias Exactas Y Naturales, Pontificia Universidad Católica del Ecuador, Calle San Pedro Y Pambahacienda, 170530, Nayón, Ecuador
| | - Bibiana E Salazar-Costa
- Centro de Investigación Para La Salud en América Latina, Facultad de Ciencias Exactas Y Naturales, Pontificia Universidad Católica del Ecuador, Calle San Pedro Y Pambahacienda, 170530, Nayón, Ecuador
| | - Juan José Bustillos
- Centro de Investigación Para La Salud en América Latina, Facultad de Ciencias Exactas Y Naturales, Pontificia Universidad Católica del Ecuador, Calle San Pedro Y Pambahacienda, 170530, Nayón, Ecuador
| | - Fabián E Saénz
- Centro de Investigación Para La Salud en América Latina, Facultad de Ciencias Exactas Y Naturales, Pontificia Universidad Católica del Ecuador, Calle San Pedro Y Pambahacienda, 170530, Nayón, Ecuador
| | - Sofía Ocaña-Mayorga
- Centro de Investigación Para La Salud en América Latina, Facultad de Ciencias Exactas Y Naturales, Pontificia Universidad Católica del Ecuador, Calle San Pedro Y Pambahacienda, 170530, Nayón, Ecuador.
| | - Cristian Koepfli
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Neil F Lobo
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
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Silva MMM, Inácio CLS, Pinheiro MPG, Ximenes MFFM. Phlebotomines (Diptera: Psychodidae) and Mosquitoes (Diptera: Culicidae) Surrounding an Environmental Protection Zone in the Metropolitan Region of Natal: Use of Light-Emitting Diode (LED) Bulbs in Entomological Surveillance. NEOTROPICAL ENTOMOLOGY 2020; 49:768-779. [PMID: 32797397 DOI: 10.1007/s13744-020-00802-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 07/10/2020] [Indexed: 06/11/2023]
Abstract
Entomological surveillance is very important for parasite and arbovirus vector control programs. Light traps with incandescent bulbs are used to attract insects and analyze the factors that contribute to the occurrence of species surrounding an environmental protection zone. Phlebotomine and mosquito abundance and their diversity were analyzed. Captures occurred monthly using six CDC light traps with two incandescent bulbs, two blue and two red LED lights. A total of 2211 phlebotomines of seven species and 4486 mosquitoes belonging to 20 taxa were captured. Different phlebotomine and mosquito species were found in the forest and peridomestic environments, with a predominance of the sand fly Evandromyia walkeri (Newstead) and the mosquito Coquillettidia venezuelensis (Theobald). There was a significant difference in the abundance of sand flies captured with the three bulbs tested, the blue bulb being the most efficient. The Shannon-Wiener diversity index showed that the trap equipped with a red LED light obtained a higher value than that of the blue LED and incandescent bulb. Analyses showed that the potential vectors and non-vectors of the two groups circulate between the forest and the peridomestic environment, suggesting an adaptation process of species to the altered environment. An incandescent light bulb can be substituted by an LED bulb, without compromising the sensitivity of the method. A blue LED is indicated for the abundant capture of mosquitoes and sand flies, while a red LED obtains a better result in terms of species diversity per capture.
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Affiliation(s)
- M M M Silva
- Lab de Pesquisa em Entomologia, Centro de Biociências, Univ Federal do Rio Grande do Norte (UFRN), Natal, RN, Brasil
| | - C L S Inácio
- Lab de Pesquisa em Entomologia, Centro de Biociências, Univ Federal do Rio Grande do Norte (UFRN), Natal, RN, Brasil
| | - M P G Pinheiro
- Lab de Pesquisa em Entomologia, Centro de Biociências, Univ Federal do Rio Grande do Norte (UFRN), Natal, RN, Brasil
- Prefeitura do Natal, Secretaria Municipal de Educação, Natal, RN, Brasil
| | - M F F M Ximenes
- Lab de Pesquisa em Entomologia, Centro de Biociências, Univ Federal do Rio Grande do Norte (UFRN), Natal, RN, Brasil.
- Depto de Microbiologia e Parasitologia, Centro de Biociências, UFRN, Natal, RN, Brasil.
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Li Y, Zhou G, Zhong S, Wang X, Zhong D, Hemming-Schroeder E, Yi G, Fu F, Fu F, Cui L, Cui G, Yan G. Spatial heterogeneity and temporal dynamics of mosquito population density and community structure in Hainan Island, China. Parasit Vectors 2020; 13:444. [PMID: 32887654 PMCID: PMC7650291 DOI: 10.1186/s13071-020-04326-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 08/30/2020] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Mosquitoes are vectors of many tropical diseases. Understanding the ecology of local mosquito vectors, such as species composition, distributions, population dynamics, and species diversity is important for designing the optimal strategy to control the mosquito-borne diseases. METHODS Entomological surveillance of adult mosquitoes was conducted in five sites representing different ecological settings across Hainan Island from January to December of 2018 using BG Sentinel (BGS) traps and Centers for Disease Prevention and Control (CDC) light traps. In each site, we selected three areas representing urban, suburban and rural settings. Eighteen trap-days were sampled in each setting at each site, and CDC light traps and BGS traps were setup simultaneously. Mosquito species composition, distribution, population dynamics, and species diversity were analyzed. Mosquito densities were compared between different study sites and between different settings. RESULTS Nine species of mosquitoes belonging to four genera were identified. Culex quinquefasciatus (80.8%), Armigeres subalbatus (13.0%) and Anopheles sinensis (3.1%) were the top three species collected by CDC light traps; Cx. quinquefasciatus (91.9%), Ae. albopictus (5.1%), and Ar. subalbatus (2.8%) were the top three species collected by BGS traps. Predominant species varied among study sites. The population dynamics of Ae. albopictus, An. sinensis and Cx. quinquefasciatus showed clear seasonal variation regardless of study sites with a varied peak season for different species. Mosquito abundance of all species showed significant differences among different study sites and among urban, suburban and rural areas. Danzhou had the highest mosquito biodiversity, with an α, β, and Gini-Simpson biodiversity index of 8, 1.13 and 0.42, respectively. BGS traps captured Aedes mosquito at a higher efficiency than CDC light traps, whereas CDC light traps captured significantly more Anopheles and Armigeres mosquitoes than BGS traps. CONCLUSIONS Mosquitoes were abundant on Hainan Island with clear seasonality and spatial heterogeneity. Population density, species composition, distribution, and species diversity were strongly affected by the natural environment. Different tools are required for the surveillance of different mosquito species.
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Affiliation(s)
- Yiji Li
- Department of Pathogen Biology, Hainan Medical University, Haikou, Hainan China
- Program in Public Health, College of Health Sciences, University of California, Irvine, CA 92697 USA
| | - Guofa Zhou
- Program in Public Health, College of Health Sciences, University of California, Irvine, CA 92697 USA
| | - Saifeng Zhong
- Department of Pathogen Biology, Hainan Medical University, Haikou, Hainan China
| | - Xiaoming Wang
- Program in Public Health, College of Health Sciences, University of California, Irvine, CA 92697 USA
| | - Daibin Zhong
- Program in Public Health, College of Health Sciences, University of California, Irvine, CA 92697 USA
| | | | - Guohui Yi
- Public Research Laboratory, Hainan Medical University, Haikou, Hainan China
| | - Fengyang Fu
- Department of Medical Technology, Chongqing Medical and Pharmaceutical College, Chongqing, China
| | - Faxing Fu
- Department of Pathogen Biology, Hainan Medical University, Haikou, Hainan China
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612 USA
| | - Guzhen Cui
- Key Laboratory of Medical Microbiology and Parasitology of Education Department of Guizhou, School of Basic Medical Science, Guizhou Medical University, Guiyang, China
- Key Laboratory of Endemic and Ethnic Diseases Ministry of Education, Guiyang, China
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California, Irvine, CA 92697 USA
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Sougoufara S, Ottih EC, Tripet F. The need for new vector control approaches targeting outdoor biting Anopheline malaria vector communities. Parasit Vectors 2020; 13:295. [PMID: 32522290 PMCID: PMC7285743 DOI: 10.1186/s13071-020-04170-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 06/04/2020] [Indexed: 12/13/2022] Open
Abstract
Since the implementation of Roll Back Malaria, the widespread use of insecticide-treated nets (ITNs) and indoor residual spraying (IRS) is thought to have played a major part in the decrease in mortality and morbidity achieved in malaria-endemic regions. In the past decade, resistance to major classes of insecticides recommended for public health has spread across many malaria vector populations. Increasingly, malaria vectors are also showing changes in vector behaviour in response to current indoor chemical vector control interventions. Changes in the time of biting and proportion of indoor biting of major vectors, as well as changes in the species composition of mosquito communities threaten the progress made to control malaria transmission. Outdoor biting mosquito populations contribute to malaria transmission in many parts of sub-Saharan Africa and pose new challenges as they cannot be reliably monitored or controlled using conventional tools. Here, we review existing and novel approaches that may be used to target outdoor communities of malaria vectors. We conclude that scalable tools designed specifically for the control and monitoring of outdoor biting and resting malaria vectors with increasingly complex and dynamic responses to intensifying malaria control interventions are urgently needed. These are crucial for integrated vector management programmes designed to challenge current and future vector populations.
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Affiliation(s)
- Seynabou Sougoufara
- Centre of Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
| | - Emmanuel Chinweuba Ottih
- Centre of Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
| | - Frederic Tripet
- Centre of Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
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Degefa T, Yewhalaw D, Zhou G, Atieli H, Githeko AK, Yan G. Evaluation of human-baited double net trap and human-odour-baited CDC light trap for outdoor host-seeking malaria vector surveillance in Kenya and Ethiopia. Malar J 2020; 19:174. [PMID: 32381009 PMCID: PMC7206766 DOI: 10.1186/s12936-020-03244-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 04/23/2020] [Indexed: 11/19/2022] Open
Abstract
Background Surveillance of outdoor host-seeking malaria vectors is crucial to monitor changes in vector biting behaviour and evaluate the impact of vector control interventions. Human landing catch (HLC) has been considered the most reliable and gold standard surveillance method to estimate human-biting rates. However, it is labour-intensive, and its use is facing an increasing ethical concern due to potential risk of exposure to infectious mosquito bites. Thus, alternative methods are required. This study was conducted to evaluate the performance of human-odour-baited CDC light trap (HBLT) and human-baited double net trap (HDNT) for outdoor host-seeking malaria vector surveillance in Kenya and Ethiopia. Methods The sampling efficiency of HBLT and HDNT was compared with CDC light trap and HLC using Latin Square Design in Ahero and Iguhu sites, western Kenya and Bulbul site, southwestern Ethiopia between November 2015 and December 2018. The differences in Anopheles mosquito density among the trapping methods were compared using generalized linear model. Results Overall, 16,963 female Anopheles mosquitoes comprising Anopheles gambiae sensu lato (s.l.), Anopheles funestus s.l., Anopheles pharoensis, Anopheles coustani and Anopheles squamosus were collected. PCR results (n = 552) showed that Anopheles arabiensis was the only member of An. gambiae s.l. in Ahero and Bulbul, while 15.7% An. arabiensis and 84.3% An. gambiae sensu stricto (s.s.) constituted An. gambiae s.l. in Iguhu. In Ahero, HBLT captured 2.23 times as many An. arabiensis and 2.11 times as many An. funestus as CDC light trap. In the same site, HDNT yielded 3.43 times more An. arabiensis and 3.24 times more An. funestus than HBLT. In Iguhu, the density of Anopheles mosquitoes did not vary between the traps (p > 0.05). In Bulbul, HBLT caught 2.19 times as many An. arabiensis as CDC light trap, while HDNT caught 6.53 times as many An. arabiensis as CDC light trap. The mean density of An. arabiensis did not vary between HDNT and HLC (p = 0.098), whereas the HLC yielded significantly higher density of An. arabiensis compared to HBLT and CDC light trap. There was a significant density-independent positive correlation between HDNT and HLC (r = 0.69). Conclusion This study revealed that both HBLT and HDNT caught higher density of malaria vectors than conventional CDC light trap. Moreover, HDNT yielded a similar vector density as HLC, suggesting that it could be an alternative tool to HLC for outdoor host-seeking malaria vector surveillance.
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Affiliation(s)
- Teshome Degefa
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia. .,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia.,Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Guofa Zhou
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Harrysone Atieli
- School of Public Health and Community Development, Maseno University, Kisumu, Kenya
| | - Andrew K Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
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Swai JK, Mmbando AS, Ngowo HS, Odufuwa OG, Finda MF, Mponzi W, Nyoni AP, Kazimbaya D, Limwagu AJ, Njalambaha RM, Abbasi S, Moore SJ, Schellenberg J, Lorenz LM, Okumu FO. Protecting migratory farmers in rural Tanzania using eave ribbons treated with the spatial mosquito repellent, transfluthrin. Malar J 2019; 18:414. [PMID: 31823783 PMCID: PMC6905030 DOI: 10.1186/s12936-019-3048-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 12/02/2019] [Indexed: 01/08/2023] Open
Abstract
Background Many subsistence farmers in rural southeastern Tanzania regularly relocate to distant farms in river valleys to tend to crops for several weeks or months each year. While there, they live in makeshift semi-open structures, usually far from organized health systems and where insecticide-treated nets (ITNs) do not provide adequate protection. This study evaluated the potential of a recently developed technology, eave ribbons treated with the spatial repellent transfluthrin, for protecting migratory rice farmers in rural southeastern Tanzania against indoor-biting and outdoor-biting mosquitoes. Methods In the first test, eave ribbons (0.1 m × 24 m each) treated with 1.5% transfluthrin solution were compared to untreated ribbons in 24 randomly selected huts in three migratory communities over 48 nights. Host-seeking mosquitoes indoors and outdoors were monitored nightly (18.00–07.00 h) using CDC light traps and CO2-baited BG malaria traps, respectively. The second test compared efficacies of eave ribbons treated with 1.5% or 2.5% transfluthrin in 12 huts over 21 nights. Finally, 286 farmers were interviewed to assess perceptions about eave ribbons, and their willingness to pay for them. Results In the two experiments, when treated eave ribbons were applied, the reduction in indoor densities ranged from 56 to 77% for Anopheles arabiensis, 36 to 60% for Anopheles funestus, 72 to 84% for Culex, and 80 to 98% for Mansonia compared to untreated ribbons. Reduction in outdoor densities was 38 to 77% against An. arabiensis, 36 to 64% against An. funestus, 63 to 88% against Culex, and 47 to 98% against Mansonia. There was no difference in protection between the two transfluthrin doses. In the survey, 58% of participants perceived the ribbons to be effective in reducing mosquito bites. Ninety per cent were willing to pay for the ribbons, the majority of whom were willing to pay but less than US$2.17 (5000 TZS), one-third of the current prototype cost. Conclusions Transfluthrin-treated eave ribbons can protect migratory rice farmers, living in semi-open makeshift houses in remote farms, against indoor-biting and outdoor-biting mosquitoes. The technology is acceptable to users and could potentially complement ITNs. Further studies should investigate durability and epidemiological impact of eave ribbons, and the opportunities for improving affordability to users.
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Affiliation(s)
- Johnson K Swai
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania.
| | - Arnold S Mmbando
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Halfan S Ngowo
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Olukayode G Odufuwa
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Marceline F Finda
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania.,School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Winifrida Mponzi
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Anna P Nyoni
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Deogratius Kazimbaya
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Alex J Limwagu
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Rukiyah M Njalambaha
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Saidi Abbasi
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Sarah J Moore
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania.,Swiss Tropical and Public Health Institute, Socinstrasse. 57, 4002, Basel 4, Switzerland.,University of Basel, St. Petersplatz 1, 4002, Basel, Switzerland
| | - Joanna Schellenberg
- Department of Disease Control, Faculty of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Lena M Lorenz
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania.,Department of Disease Control, Faculty of Infectious and Tropical Disease, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Fredros O Okumu
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK.,School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.,School of Life Science and Bioengineering, The Nelson Mandela African, Institution of Science and Technology, P. O. Box 447, Arusha, Tanzania
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Sanou A, Moussa Guelbéogo W, Nelli L, Hyacinth Toé K, Zongo S, Ouédraogo P, Cissé F, Mirzai N, Matthiopoulos J, Sagnon N, Ferguson HM. Evaluation of mosquito electrocuting traps as a safe alternative to the human landing catch for measuring human exposure to malaria vectors in Burkina Faso. Malar J 2019; 18:386. [PMID: 31791336 PMCID: PMC6889701 DOI: 10.1186/s12936-019-3030-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 11/24/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Measuring human exposure to mosquito bites is a crucial component of vector-borne disease surveillance. For malaria vectors, the human landing catch (HLC) remains the gold standard for direct estimation of exposure. This method, however, is controversial since participants risk exposure to potentially infected mosquito bites. Recently an exposure-free mosquito electrocuting trap (MET) was developed to provide a safer alternative to the HLC. Early prototypes of the MET performed well in Tanzania but have yet to be tested in West Africa, where malaria vector species composition, ecology and behaviour are different. The performance of the MET relative to HLC for characterizing mosquito vector population dynamics and biting behaviour in Burkina Faso was evaluated. METHODS A longitudinal study was initiated within 12 villages in Burkina Faso in October 2016. Host-seeking mosquitoes were sampled monthly using HLC and MET collections over 14 months. Collections were made at 4 households on each night, with METs deployed inside and outside at 2 houses, and HLC inside and outside at another two. Malaria vector abundance, species composition, sporozoite rate and location of biting (indoor versus outdoor) were recorded. RESULTS In total, 41,800 mosquitoes were collected over 324 sampling nights, with the major malaria vector being Anopheles gambiae sensu lato (s.l.) complex. Overall the MET caught fewer An. gambiae s.l. than the HLC (mean predicted number of 0.78 versus 1.82 indoors, and 1.05 versus 2.04 outdoors). However, MET collections gave a consistent representation of seasonal dynamics in vector populations, species composition, biting behaviour (location and time) and malaria infection rates relative to HLC. As the relative performance of the MET was somewhat higher in outdoor versus indoor settings, this trapping method slightly underestimated the proportion of bites preventable by LLINs compared to the HLC (MET = 82.08%; HLC = 87.19%). CONCLUSIONS The MET collected proportionately fewer mosquitoes than the HLC. However, estimates of An. gambiae s.l. density in METs were highly correlated with HLC. Thus, although less sensitive, the MET is a safer alternative than the HLC. Its use is recommended particularly for sampling vectors in outdoor environments where it is most sensitive.
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Affiliation(s)
- Antoine Sanou
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ, UK.
- Centre National de Recherche et de Formation sur le Paludisme, Av. Kunda nyooré, PO Box 2208, Ouagadougou, Burkina Faso.
| | - W Moussa Guelbéogo
- Centre National de Recherche et de Formation sur le Paludisme, Av. Kunda nyooré, PO Box 2208, Ouagadougou, Burkina Faso
| | - Luca Nelli
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ, UK
| | - K Hyacinth Toé
- Centre National de Recherche et de Formation sur le Paludisme, Av. Kunda nyooré, PO Box 2208, Ouagadougou, Burkina Faso
| | - Soumanaba Zongo
- Centre National de Recherche et de Formation sur le Paludisme, Av. Kunda nyooré, PO Box 2208, Ouagadougou, Burkina Faso
| | - Pierre Ouédraogo
- Centre National de Recherche et de Formation sur le Paludisme, Av. Kunda nyooré, PO Box 2208, Ouagadougou, Burkina Faso
| | - Fatoumata Cissé
- Centre National de Recherche et de Formation sur le Paludisme, Av. Kunda nyooré, PO Box 2208, Ouagadougou, Burkina Faso
| | - Nosrat Mirzai
- Bioelectronics Units, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ, UK
| | - Jason Matthiopoulos
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ, UK
| | - N'falé Sagnon
- Centre National de Recherche et de Formation sur le Paludisme, Av. Kunda nyooré, PO Box 2208, Ouagadougou, Burkina Faso
| | - Heather M Ferguson
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ, UK
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Biting patterns of malaria vectors of the lower Shire valley, southern Malawi. Acta Trop 2019; 197:105059. [PMID: 31194960 DOI: 10.1016/j.actatropica.2019.105059] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 06/06/2019] [Accepted: 06/07/2019] [Indexed: 12/13/2022]
Abstract
Assessing the biting behaviour of malaria vectors plays an integral role in understanding the dynamics of malaria transmission in a region. Biting times and preference for biting indoors or outdoors varies among mosquito species and across regions. These behaviours may also change over time in response to vector control measures such as long-lasting insecticidal nets (LLINs). Data on these parameters can provide the sites and times at which different interventions would be effective for vector control. This study assessed the biting patterns of malaria vectors in Chikwawa district, southern Malawi. The study was conducted during the dry and wet seasons in 2016 and 2017, respectively. In each season, mosquitoes were collected indoors and outdoors for 24 nights in six houses per night using the human landing catch. Volunteers were organized into six teams of two individuals, whereby three teams collected mosquitoes indoors and the other three collected mosquitoes outdoors each night, and the teams were rotated among twelve houses. All data were analyzed using Poisson log-linear models. The most abundant species were Anopheles gambiae sensu lato (primarily An. arabiensis) and An. funestus s.l. (exclusively An. funestus s.s.). During the dry season, the biting activity of An. gambiaes.l. was constant outdoors across the categorized hours (18:00 h to 08:45 h), but highest in the late evening hours (21:00 h to 23:45 h) during the wet season. The biting activity of An. funestus s.l. was highest in the late evening hours (21:00 h to 23:45 h) during the dry season and in the late night hours (03:00 h to 05:45 h) during the wet season. Whereas the number of An. funestuss.l. biting was constant (P = 0.662) in both seasons, that of An. gambiaes.l. was higher during the wet season than in the dry season (P = 0.001). Anopheles gambiae s.l. was more likely to bite outdoors than indoors in both seasons. During the wet season, An. funestus s.l. was more likely to bite indoors than outdoors but during the dry season, the bites were similar both indoors and outdoors. The biting activity that occurred in the early and late evening hours, both indoors and outdoors coincides with the times at which individuals may still be awake and physically active, and therefore unprotected by LLINs. Additionally, a substantial number of anopheline bites occurred outdoors. These findings imply that LLINs would only provide partial protection from malaria vectors, which would affect malaria transmission in this area. Therefore, protection against bites by malaria mosquitoes in the early and late evening hours is essential and can be achieved by designing interventions that reduce vector-host contacts during this period.
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Climatic Conditions: Conventional and Nanotechnology-Based Methods for the Control of Mosquito Vectors Causing Human Health Issues. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16173165. [PMID: 31480254 PMCID: PMC6747303 DOI: 10.3390/ijerph16173165] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/25/2019] [Accepted: 08/27/2019] [Indexed: 12/12/2022]
Abstract
Climate variability is highly impacting on mosquito-borne diseases causing malaria and dengue fever across the globe. Seasonal variability change in temperature and rainfall patterns are impacting on human health. Mosquitoes cause diseases like dengue fever, yellow fever, malaria, Chikungunya, West Nile and Japanese encephalitis. According to estimations by health organizations, annually one million human deaths are caused by vector-borne diseases, and dengue fever has increased about 30-fold over the past 50 years. Similarly, over 200 million cases of malaria are being reported annually. Mosquito-borne diseases are sensitive to temperature, humidity and seasonal variability. Both conventional (environmental, chemical, mechanical, biological etc.) and nanotechnology-based (Liposomes, nano-suspensions and polymer-based nanoparticles) approaches are used for the eradication of Malaria and dengue fever. Now green approaches are used to eradicate mosquitoes to save human health without harming the environment. In this review, the impact of climatic conditions on mosquito-borne diseases along with conventional and nanotechnology-based approaches used for controlling malaria and dengue fever have been discussed. Important recommendations have been made for people to stay healthy.
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Sallum MAM, Conn JE, Bergo ES, Laporta GZ, Chaves LSM, Bickersmith SA, de Oliveira TMP, Figueira EAG, Moresco G, Olívêr L, Struchiner CJ, Yakob L, Massad E. Vector competence, vectorial capacity of Nyssorhynchus darlingi and the basic reproduction number of Plasmodium vivax in agricultural settlements in the Amazonian Region of Brazil. Malar J 2019; 18:117. [PMID: 30947726 PMCID: PMC6449965 DOI: 10.1186/s12936-019-2753-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 03/28/2019] [Indexed: 11/10/2022] Open
Abstract
Background Brazilian malaria control programmes successfully reduced the incidence and mortality rates from 2005 to 2016. Since 2017, increased malaria has been reported across the Amazon. Few field studies focus on the primary malaria vector in high to moderate endemic areas, Nyssorhynchus darlingi, as the key entomological component of malaria risk, and on the metrics of Plasmodium vivax propagation in Amazonian rural communities. Methods Human landing catch collections were carried out in 36 houses of 26 communities in five municipalities in the Brazilian states of Acre, Amazonas and Rondônia states, with API (> 30). In addition, data on the number of locally acquired symptomatic infections were employed in mathematical modelling analyses carried out to determine Ny. darlingi vector competence and vectorial capacity to P. vivax; and to calculate the basic reproduction number for P. vivax. Results Entomological indices and malaria metrics ranged among localities: prevalence of P. vivax infection in Ny. darlingi, from 0.243% in Mâncio Lima, Acre to 3.96% in Machadinho D’Oeste, Rondônia; daily human-biting rate per person from 23 ± 1.18 in Cruzeiro do Sul, Acre, to 66 ± 2.41 in Lábrea, Amazonas; vector competence from 0.00456 in São Gabriel da Cachoeira, Amazonas to 0.04764 in Mâncio Lima, Acre; vectorial capacity from 0.0836 in Mâncio Lima, to 1.5 in Machadinho D’Oeste. The estimated R0 for P. vivax (PvR0) was 3.3 in Mâncio Lima, 7.0 in Lábrea, 16.8 in Cruzeiro do Sul, 55.5 in São Gabriel da Cachoeira, and 58.7 in Machadinho D’Oeste. Correlation between P. vivax prevalence in Ny. darlingi and vector competence was non-linear whereas association between prevalence of P. vivax in mosquitoes, vectorial capacity and R0 was linear and positive. Conclusions In spite of low vector competence of Ny. darlingi to P. vivax, parasite propagation in the human population is enhanced by the high human-biting rate, and relatively high vectorial capacity. The high PvR0 values suggest hyperendemicity in Machadinho D’Oeste and São Gabriel da Cachoeira at levels similar to those found for P. falciparum in sub-Saharan Africa regions. Mass screening for parasite reservoirs, effective anti-malarial drugs and vector control interventions will be necessary to shrinking transmission in Amazonian rural communities, Brazil. Electronic supplementary material The online version of this article (10.1186/s12936-019-2753-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Maria Anice M Sallum
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, SP, Brazil.
| | - Jan E Conn
- Wadsworth Center, New York State Department of Health, Albany, NY, USA.,Department of Biomedical Sciences, School of Public Health, State University of New York, Albany, NY, USA
| | - Eduardo S Bergo
- Superintendência de Controle de Endemias, Secretaria de Estado da Saúde de São Paulo, Araraquara, SP, Brazil
| | - Gabriel Z Laporta
- Setor de Pós-graduação, Pesquisa e Inovação, Faculdade de Medicina do ABC, Santo André, SP, Brazil
| | - Leonardo S M Chaves
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, SP, Brazil
| | | | - Tatiane M P de Oliveira
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, SP, Brazil
| | | | - Gilberto Moresco
- Secretaria de Vigilância em Saúde, Departamento de Vigilância das Doenças Transmissíveis, Ministério da Saúde, Brasília, DF, Brazil
| | - Lêuda Olívêr
- Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Claudio J Struchiner
- Departamento de Doenças Endêmicas Samuel Pessoa, Escola Nacional de Saúde Pública, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil
| | - Laith Yakob
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Eduardo Massad
- Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.,Escola de Matemática Aplicada, Fundação Getúlio Vargas, Rio de Janeiro, RJ, Brazil
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Meza FC, Kreppel KS, Maliti DF, Mlwale AT, Mirzai N, Killeen GF, Ferguson HM, Govella NJ. Mosquito electrocuting traps for directly measuring biting rates and host-preferences of Anopheles arabiensis and Anopheles funestus outdoors. Malar J 2019; 18:83. [PMID: 30885205 PMCID: PMC6423841 DOI: 10.1186/s12936-019-2726-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 03/13/2019] [Indexed: 11/26/2022] Open
Abstract
Background Mosquito biting rates and host preferences are crucial determinants of human exposure to vector-borne diseases and the impact of vector control measures. The human landing catch (HLC) is a gold standard method for measuring human exposure to bites, but presents risks to participants by requiring some exposure to mosquito vectors. Mosquito electrocuting traps (METs) represent an exposure-free alternative to HLCs for measuring human exposure to malaria vectors. However, original MET prototypes were too small for measuring whole-body biting rates on humans or large animals like cattle. Here a much larger MET capable of encompassing humans or cattle was designed, and its performance was evaluated relative to both the original small MET and HLC and for quantifying malaria vector host preferences. Methods Human landing catch, small human-baited METs (MET-SH), and large METs baited with either a human (MET-LH) or calves (MET-LC) were simultaneously used to capture wild malaria vectors outdoors in rural southern Tanzania. The four capture methods were compared in a Latin-square design over 20 nights. Malaria vector host preferences were estimated through comparison of the number of mosquitoes caught by large METs baited with either humans or cattle. Results The MET-LH caught more than twice as many Anopheles arabiensis than either the MET-SH or HLC. It also caught higher number of Anopheles funestus sensu lato (s.l.) compared to the MET-SH or HLC. Similar numbers of An. funestus sensu stricto (s.s.) were caught in MET-LH and MET-SH collections. Catches of An. arabiensis with human or cattle-baited large METs were similar, indicating no clear preference for either host. In contrast, An. funestus s.s. exhibited a strong, but incomplete preference for humans. Conclusions METs are a sensitive, practical tool for assessing mosquito biting rates and host preferences, and represent a safer alternative to the HLC. Additionally these findings suggest the HLC underestimate whole-body human exposure. MET collections indicated the An. funestus s.s. population in this setting had a higher than expected attack rate on cattle, potentially making eliminating of this species more difficult with human-targetted control measures. Supplementary vector control tools targetted at livestock may be required to effectively tackle this species.
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Affiliation(s)
- Felician C Meza
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Off Mlabani Passage, P.O. Box 53, Ifakara, Tanzania.
| | - Katharina S Kreppel
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Off Mlabani Passage, P.O. Box 53, Ifakara, Tanzania.,Animal Health and Comparative Medicine, Institute of Biodiversity, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ, UK
| | - Deodatus F Maliti
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Off Mlabani Passage, P.O. Box 53, Ifakara, Tanzania.,Animal Health and Comparative Medicine, Institute of Biodiversity, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ, UK
| | - Amos T Mlwale
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Off Mlabani Passage, P.O. Box 53, Ifakara, Tanzania
| | - Nosrat Mirzai
- Bioelectronics Unit, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ, UK
| | - Gerry F Killeen
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Off Mlabani Passage, P.O. Box 53, Ifakara, Tanzania.,Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Heather M Ferguson
- Animal Health and Comparative Medicine, Institute of Biodiversity, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ, UK
| | - Nicodem J Govella
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Off Mlabani Passage, P.O. Box 53, Ifakara, Tanzania.,Animal Health and Comparative Medicine, Institute of Biodiversity, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ, UK
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Silva FS, Costa-Neta BM, de Sousa de Almeida M, de Araújo EC, Aguiar JVC. Field performance of a low cost, simple-to-build, non-motorized light-emitting diode (LED) trap for capturing adult Anopheles mosquitoes (Diptera: Culicidae). Acta Trop 2019; 190:9-12. [PMID: 30385219 DOI: 10.1016/j.actatropica.2018.10.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 10/27/2018] [Accepted: 10/27/2018] [Indexed: 10/28/2022]
Abstract
In this paper, a non-powered trap equipped with light-emitting diodes (LEDs) designed for capturing small night-flying insects was field-evaluated for sampling anopheline mosquitoes. This new light trap, referred to as the Silva trap, was compared with the Centers for Disease Control and Prevention (CDC) miniature light trap in a livestock area in northeastern Brazil. Light traps were operated from 18:00 to 06:00 between July and August 2018, over a 12-night period. A total of 3124 specimens and eight species were collected. Anopheles (Nyssorhynchus) argyritarsis was the prevalent species, followed by A. (Nys) triannulatus s.l., A. (Nys) goeldii, A. (Nys) evansae, A. (Nys) rangeli, A. (Nys) galvaoi, A. (Nys) darlingi and A. (Nys) albitarsis s.l. The total number of anopheline mosquitoes captured with the Silva trap was higher than the number of individuals captured with the CDC light trap, but no significant difference between the two trapping methods was found. Concerning the damaged specimens, the Silva trap damaged significantly less mosquitoes than the CDC light trap. According to these results, the Silva trap has acceptable performance in being an efficient tool for sampling anopheline mosquitoes, mainly in comparison with the CDC light trap. The Silva trap has a number of advantages over other trapping devices that collect questing mosquitoes and these advantages are pointed out and discussed.
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Peck GW, Castro-Llanos F, López-Sifuentes VM, Vásquez GM, Lindroth E. Comparative Analysis of Mosquito Trap Counts In the Peruvian Amazon: Effect of Trap Type and Other Covariates On Counts and Diversity. JOURNAL OF THE AMERICAN MOSQUITO CONTROL ASSOCIATION 2018; 34:291-301. [PMID: 31442143 DOI: 10.2987/17-6724.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Efficient detection of multiple species of adult mosquitoes in various habitats using effective traps is a crucial 1st step in any disease prevention program. Novel trap types that target tropical vectors of human diseases require field testing in the habitat of the vector-disease system in question. This paper analyzes a series of mosquito trapping studies conducted at Mapacocha, San Juan Bautista District, Loreto, Peru, during August-September 2013 and April-May 2014. Six trap configurations were evaluated in forest and rural locations. Adult mosquito counts were analyzed using full Bayesian inference of multilevel generalized linear models and posterior probability point estimates of the difference of means of the combined trap catch by trap type comparisons of all species. Light traps (Centers for Disease Control and Prevention [CDC] incandescent, white light-emitting diode [LED], and ultraviolet LED) caught greater numbers of mosquitoes compared with traps baited with yeast-generated CO2 and Biogents Sentinel™ traps (battery powered traps without light and passive box traps). However, diversity measures (species richness, evenness, and similarity) were consistently nearly equal among trap types. Arbovirus vectors were more common in forest locations, while malaria vectors were more common near human habitations. Location had a significant effect on trap effectiveness and mosquito diversity, with traps from forest locations having greater numbers and greater species richness, compared with traps set near human habitations. The results of this study will inform mosquito surveillance trap choices in remote regions of central South America, including regions with emerging tropical diseases, such and dengue and Zika virus.
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Batista EPA, Ngowo H, Opiyo M, Shubis GK, Meza FC, Siria DJ, Eiras AE, Okumu FO. Field evaluation of the BG-Malaria trap for monitoring malaria vectors in rural Tanzanian villages. PLoS One 2018; 13:e0205358. [PMID: 30296287 PMCID: PMC6175526 DOI: 10.1371/journal.pone.0205358] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 09/24/2018] [Indexed: 11/19/2022] Open
Abstract
BG-Malaria (BGM) trap is a simple adaptation of the widely-used BG-Sentinel trap (BGS). It is proven to be highly effective for trapping the Brazilian malaria vector, Anopheles darlingi, in field conditions, and the African vector, Anopheles arabiensis, under controlled semi-field environments, but has not been field-tested in Africa. Here, we validated the BGM for field sampling of malaria vectors in south-eastern Tanzania. Using a series of Latin-Square experiments conducted nightly (6pm-7am) in rural villages, we compared mosquito catches between BGM, BGS and human landing catches (HLC). We also compared BGMs baited with different attractants (Ifakara-blend, Mbita-blend, BG-Lure and CO2). Lastly, we tested BGMs baited with Ifakara-blend from three odour-dispensing methods (BG-Cartridge, BG-Sachet and Nylon strips). One-tenth of the field-collected female Anopheles gambiae s.l. and Anopheles funestus were dissected to assess parity. BGM captured more An. gambiae s.l. than BGS (p < 0.001), but HLC caught more than either trap (p < 0.001). However, BGM captured more An. funestus than HLC. Proportions of parous An. gambiae s.l. and An. funestus consistently exceeded 50%, with no significant difference between methods. While the dominant species caught by HLC was An. gambiae s.l. (56.0%), followed by Culex spp. (33.1%) and Mansonia spp. (6.0%), the BGM caught mostly Culex (81.6%), followed by An. gambiae s.l. (10.6%) and Mansonia (5.8%). The attractant-baited BGMs were all significantly superior to un-baited controls (p < 0.001), although no difference was found between the specific attractants. The BG-Sachet was the most efficient dispenser for capturing An. gambiae s.l. (14.5(2.75–42.50) mosquitoes/trap/night), followed by BG-Cartridge (7.5(1.75–26.25)). The BGM caught more mosquitoes than BGS in field-settings, but sampled similar species diversity and physiological states as BGS. The physiological states of malaria vectors caught in BGM and BGS were similar to those naturally attempting to bite humans (HLC). The BGM was most efficient when baited with Ifakara blend, dispensed from BG-Sachet. We conclude that though BGM traps have potential for field-sampling of host-seeking African malaria vectors with representative physiological states, both BGM and BGS predominantly caught more culicines than Anopheles, compared to HLC, which caught mostly An. gambiae s.l.
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Affiliation(s)
- Elis P. A. Batista
- Laboratório de Ecologia Química de Insetos Vetores, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- * E-mail:
| | - Halfan Ngowo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Mercy Opiyo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Gasper K. Shubis
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Felician C. Meza
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Doreen J. Siria
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Alvaro E. Eiras
- Laboratório de Ecologia Química de Insetos Vetores, Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Fredros O. Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Parktown, Republic of South Africa
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
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Chaiphongpachara T, Bunyuen P, Khlaeo Chansukh K. Development of a More Effective Mosquito Trapping Box for Vector Control. ScientificWorldJournal 2018; 2018:6241703. [PMID: 30154682 PMCID: PMC6093027 DOI: 10.1155/2018/6241703] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 06/13/2018] [Accepted: 07/03/2018] [Indexed: 12/24/2022] Open
Abstract
Mosquito-borne diseases are a major public health issue in nearly all tropical and subtropical countries, making vector control imperative. The mosquito trapping box is one type of mosquito traps that is popular in some areas because it is affordable, environmentally friendly, and easy to produce. This research investigated whether the effectiveness of the mosquito trapping box could be increased through the addition of various physical factors, including a wooden frame, black cotton cloth, a fan, carbon dioxide (CO2), and heat, by testing a range of box designs in the Samut Songkhram Province, Thailand, between December 2016 and January 2017. We found that trapping boxes constructed with Pinus kesiya wood caught more mosquitoes than those constructed with two other types of wood or aluminum. We also found that mosquito trapping boxes were more effective when more factors were added, although these differences were only significant for black cotton cloth and CO2. These findings will guide the future development of mosquito trapping boxes for effective mosquito control in other areas, helping to reduce the incidence of mosquito-borne diseases.
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Affiliation(s)
| | - Ploypailin Bunyuen
- Bachelor of Public Health, College of Allied Health Sciences, Suan Sunandha Rajabhat University, Thailand
| | - Kitthisak Khlaeo Chansukh
- Department of Applied Thai Traditional Medicine, College of Allied Health Sciences, Suan Sunandha Rajabhat University, Thailand
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Costa-Neta BM, Lima-Neto AR, da Silva AA, Brito JM, Aguiar JVC, Ponte IS, Silva FS. Centers for Disease Control-type light traps equipped with high-intensity light-emitting diodes as light sources for monitoring Anopheles mosquitoes. Acta Trop 2018; 183:61-63. [PMID: 29649426 DOI: 10.1016/j.actatropica.2018.04.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/03/2018] [Accepted: 04/08/2018] [Indexed: 11/16/2022]
Abstract
In this study the phototactic response of anopheline mosquitoes to different luminous intensity light-emitting diodes (LEDs) was investigated. Centers for Disease Control-type light traps were changed by replacement of the incandescent lamps by 5 mm round type green (520 nm) and blue (470 nm) LEDs of different luminous intensities: green-LED traps with luminous intensities of 10,000, 15,000 and 20,000 millicandela (mcd) and the blue-LED traps with luminous intensities of 4000, 12,000 and 15,000 mcd. Our data showed that increasing luminous intensity has an effect on the attraction of anopheline mosquitoes to light traps, highlighting the importance of taking LEDs and light sources of high luminous intensity into account when using light-trap collections in monitoring populations of Anopheles species.
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Affiliation(s)
- Benedita Maria Costa-Neta
- Laboratory of Medical Entomology, Center for Agrarian and Environmental Sciences, Federal University of Maranhão, Chapadinha, MA, 65500-000, Brazil; Programa de Pós-Graduação em Ciências da Saúde, Universidade Federal do Maranhão, CEP: 65080-805, São Luis, Maranhão, Brazil
| | - Abdias Ribeiro Lima-Neto
- Laboratory of Medical Entomology, Center for Agrarian and Environmental Sciences, Federal University of Maranhão, Chapadinha, MA, 65500-000, Brazil
| | - Apoliana Araújo da Silva
- Laboratory of Medical Entomology, Center for Agrarian and Environmental Sciences, Federal University of Maranhão, Chapadinha, MA, 65500-000, Brazil; Programa de Pós-Graduação em Ciências da Saúde, Universidade Federal do Maranhão, CEP: 65080-805, São Luis, Maranhão, Brazil
| | - Jefferson Mesquita Brito
- Laboratory of Medical Entomology, Center for Agrarian and Environmental Sciences, Federal University of Maranhão, Chapadinha, MA, 65500-000, Brazil; Programa de Pós-Graduação em Ciências da Saúde, Universidade Federal do Maranhão, CEP: 65080-805, São Luis, Maranhão, Brazil
| | - João Vitor Castro Aguiar
- Laboratory of Medical Entomology, Center for Agrarian and Environmental Sciences, Federal University of Maranhão, Chapadinha, MA, 65500-000, Brazil
| | - Islana Silva Ponte
- Laboratory of Medical Entomology, Center for Agrarian and Environmental Sciences, Federal University of Maranhão, Chapadinha, MA, 65500-000, Brazil
| | - Francinaldo Soares Silva
- Laboratory of Medical Entomology, Center for Agrarian and Environmental Sciences, Federal University of Maranhão, Chapadinha, MA, 65500-000, Brazil; Programa de Pós-Graduação em Ciências da Saúde, Universidade Federal do Maranhão, CEP: 65080-805, São Luis, Maranhão, Brazil.
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Khan E, Barr KL, Farooqi JQ, Prakoso D, Abbas A, Khan ZY, Ashi S, Imtiaz K, Aziz Z, Malik F, Lednicky JA, Long MT. Human West Nile Virus Disease Outbreak in Pakistan, 2015-2016. Front Public Health 2018. [PMID: 29535994 PMCID: PMC5835076 DOI: 10.3389/fpubh.2018.00020] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Like most of the world, Pakistan has seen an increase in mosquito-transmitted diseases in recent years. The magnitude and distribution of these diseases are poorly understood as Pakistan does not have a nation-wide system for reporting disease. A cross-sectional study to determine which flaviviruses were causing of arboviral disease in Pakistan was instituted. West Nile virus (WNV) is a cause of seasonal fever with neurotropic findings in countries that share borders with Pakistan. Here, we describe the active and persistent circulation of WNV in humans in the southern region of Pakistan. This is the first report of WNV causing neurological disease in human patients in this country. Of 997 enrolled patients presenting with clinical features suggestive of arboviral disease, 105 were positive for WNV IgM antibodies, and 71 of these patients possessed WNV-specific neutralizing antibodies. Cross-reactivity of WNV IgM antibodies with Japanese encephalitis virus (JEV) occurred in 75 of these 105 patients. WNV co-infections with Dengue viruses were not a contributing factor for the severity of disease. Nor did prior exposure to dengue virus contribute to incidence of neurological involvement in WNV-infected patients. Patients with WNV infections were more likely to present with altered mental status, seizures, and reduced Glasgow Coma scores when compared with JEV-infected patients. Human WNV cases and vector numbers exhibited a temporal correlation with climate.
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Affiliation(s)
- Erum Khan
- Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan
| | - Kelli L Barr
- Department of Comparative Diagnostic and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Joveria Qais Farooqi
- Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan
| | - Dhani Prakoso
- Department of Comparative Diagnostic and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Alizeh Abbas
- Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan
| | - Zain Yar Khan
- Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan
| | - Shanze Ashi
- Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan
| | - Kehkashan Imtiaz
- Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan
| | - Z Aziz
- Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan
| | - Faisal Malik
- Department of Pathology and Laboratory Medicine, Aga Khan University, Karachi, Pakistan
| | - John A Lednicky
- Department of Environmental and Global Health, Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | - Maureen T Long
- Department of Comparative Diagnostic and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
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Chen T, Zhang S, Zhou SS, Wang X, Luo C, Zeng X, Guo X, Lin Z, Tu H, Sun X, Zhou H. Receptivity to malaria in the China-Myanmar border in Yingjiang County, Yunnan Province, China. Malar J 2017; 16:478. [PMID: 29162093 PMCID: PMC5699173 DOI: 10.1186/s12936-017-2126-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Accepted: 11/16/2017] [Indexed: 11/26/2022] Open
Abstract
Background The re-establishment of malaria has become an important public health issue in and out of China, and receptivity to this disease is key to its re-emergence. Yingjiang is one of the few counties with locally acquired malaria cases in the China–Myanmar border in China. This study aimed to understand receptivity to malaria in Yingjiang County, China, from June to October 2016. Methods Light-traps were employed to capture the mosquitoes in 17 villages in eight towns which were categorized into four elevation levels: level 1, 0–599 m; level 2, 600–1199 m; level 3, 1200–1799 m; and level 4, > 1800 m. Species richness, diversity, dominance and evenness were used to picture the community structure. Similarity in species composition was compared between different elevation levels. Data of seasonal abundance of mosquitoes, human biting rate, density of light-trap-captured adult mosquitoes and larvae, parous rate, and height distribution (density) of Anopheles minimus and Anopheles sinensis were collected in two towns (Na Bang and Ping Yuan) each month from June to October, 2016. Results Over the study period, 10,053 Anopheles mosquitoes were collected from the eight towns, and 15 Anopheles species were identified, the most-common of which were An. sinensis (75.4%), Anopheles kunmingensis (15.6%), and An. minimus (3.5%). Anopheles minimus was the major malaria vector in low-elevation areas (< 600 m, i.e., Na Bang town), and An. sinensis in medium-elevation areas (600–1200 m, i.e., Ping Yuan town). In Na Bang, the peak human-biting rate of An. minimus at the inner and outer sites of the village occurred in June and August 2016, with 5/bait/night and 15/bait/night, respectively. In Ping Yuan, the peak human-biting rate of An. sinensis was in August, with 9/bait/night at the inner site and 21/bait/night at the outer site. The two towns exhibited seasonal abundance with high density of the two adult vectors: The peak density of An. minimus was in June and that of An. sinensis was in August. Meanwhile, the peak larval density of An. minimus was in July, but that of An. sinensis decreased during the investigation season; the slightly acidic water suited the growth of these vectors. The parous rates of An. sinensis and An. minimus were 90.46 and 93.33%, respectively. Conclusions The Anopheles community was spread across different elevation levels. Its structure was complex and stable during the entire epidemic season in low-elevation areas at the border. The high human-biting rates, adult and larval densities, and parous rates of the two Anopheles vectors reveal an exceedingly high receptivity to malaria in the China–Myanmar border in Yingjiang County.
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Affiliation(s)
- Tianmu Chen
- Department of Malaria, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China.,Key Laboratory of Parasite and Vector Biology, Ministry of Health, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China.,WHO Collaborating Centre for Tropic Diseases, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China.,National Center for International Research on Tropical Diseases, Ministry of Science and Technology, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China
| | - Shaosen Zhang
- Department of Malaria, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China.,Key Laboratory of Parasite and Vector Biology, Ministry of Health, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China.,WHO Collaborating Centre for Tropic Diseases, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China.,National Center for International Research on Tropical Diseases, Ministry of Science and Technology, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China
| | - Shui-Sen Zhou
- Department of Malaria, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China. .,Key Laboratory of Parasite and Vector Biology, Ministry of Health, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China. .,WHO Collaborating Centre for Tropic Diseases, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China. .,National Center for International Research on Tropical Diseases, Ministry of Science and Technology, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China.
| | - Xuezhong Wang
- Yunnan Institute of Parasitic Diseases, Puer, People's Republic of China
| | - Chunhai Luo
- Yunnan Institute of Parasitic Diseases, Puer, People's Republic of China
| | - Xucan Zeng
- Yunnan Institute of Parasitic Diseases, Puer, People's Republic of China
| | - Xiangrui Guo
- Yingjiang County Center for Disease Control and Prevention, Dehong, People's Republic of China
| | - Zurui Lin
- Yunnan Institute of Parasitic Diseases, Puer, People's Republic of China
| | - Hong Tu
- Department of Malaria, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China.,Key Laboratory of Parasite and Vector Biology, Ministry of Health, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China.,WHO Collaborating Centre for Tropic Diseases, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China.,National Center for International Research on Tropical Diseases, Ministry of Science and Technology, 207 Rui Jin Er Road, Shanghai, 200025, People's Republic of China
| | - Xiaodong Sun
- Yunnan Institute of Parasitic Diseases, Puer, People's Republic of China
| | - Hongning Zhou
- Yunnan Institute of Parasitic Diseases, Puer, People's Republic of China
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50
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Costa-Neta BM, da Silva AA, Brito JM, Moraes JLP, Rebêlo JMM, Silva FS. Light-Emitting Diode (LED) Traps Improve the Light-Trapping of Anopheline Mosquitoes. JOURNAL OF MEDICAL ENTOMOLOGY 2017; 54:1699-1703. [PMID: 28968803 DOI: 10.1093/jme/tjx148] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Indexed: 06/07/2023]
Abstract
Numerous advantages over the standard incandescent lamp favor the use of light-emitting diodes (LEDs) as an alternative and inexpensive light source for sampling medically important insects in surveillance studies. Previously published studies examined the response of mosquitoes to different wavelengths, but data on anopheline mosquito LED attraction are limited. Center for Disease Control and Prevention-type light traps were modified by replacing the standard incandescent lamp with 5-mm LEDs, one emitting at 520 nm (green) and the other at 470 nm (blue). To test the influence of moon luminosity on LED catches, the experiments were conducted during the four lunar phases during each month of the study period. A total of 1,845 specimens representing eight anopheline species were collected. Anopheles (Nyssorhynchus) evansae (35.2%) was the most frequently collected, followed by An. (Nys.) triannulatus (21.9%), An. (Nys.) goeldii (12.9%), and An. (Nys.) argyritarsis (11.5%). The green LED was the most attractive light source, accounting for 43.3% of the individuals collected, followed by the blue (31.8%) and control (24.9%) lights. The LED traps were significantly more attractive than the control, independent of the lunar phase. Light trapping of anopheline mosquitoes was more efficient when the standard incandescent lamp was replaced with LEDs, regardless of the moon phase. The efficiency of LEDs improves light trapping results, and it is suggested that the use of LEDs as an attractant for anopheline mosquitoes should be taken into consideration when sampling anopheline mosquitoes.
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Affiliation(s)
- B M Costa-Neta
- Laboratory of Medical Entomology, Center for Agrarian and Environmental Sciences, Federal University of Maranhão, CEP: 65500-00, Chapadinha, MA, Brasil
- Laboratório de Entomologia e Vetores, Departamento de Biologia, Universidade Federal do Maranhão, CEP: 65080-805, São Luís, MA, Brasil
- Programa de Pós-Graduação em Ciências da Saúde, Universidade Federal do Maranhão, CEP: 65080-805, São Luís, MA, Brasil
| | - A A da Silva
- Laboratory of Medical Entomology, Center for Agrarian and Environmental Sciences, Federal University of Maranhão, CEP: 65500-00, Chapadinha, MA, Brasil
- Programa de Pós-Graduação em Ciências da Saúde, Universidade Federal do Maranhão, CEP: 65080-805, São Luís, MA, Brasil
| | - J M Brito
- Laboratory of Medical Entomology, Center for Agrarian and Environmental Sciences, Federal University of Maranhão, CEP: 65500-00, Chapadinha, MA, Brasil
- Programa de Pós-Graduação em Ciências da Saúde, Universidade Federal do Maranhão, CEP: 65080-805, São Luís, MA, Brasil
- Laboratório de Imunofisiologia, Departamento de Patologia, Universidade Federal do Maranhão, CEP: 65080-805, São Luís, MA, Brasil
| | - J L P Moraes
- Laboratório de Entomologia e Vetores, Departamento de Biologia, Universidade Federal do Maranhão, CEP: 65080-805, São Luís, MA, Brasil
| | - J M M Rebêlo
- Laboratório de Entomologia e Vetores, Departamento de Biologia, Universidade Federal do Maranhão, CEP: 65080-805, São Luís, MA, Brasil
- Programa de Pós-Graduação em Ciências da Saúde, Universidade Federal do Maranhão, CEP: 65080-805, São Luís, MA, Brasil
| | - F S Silva
- Laboratory of Medical Entomology, Center for Agrarian and Environmental Sciences, Federal University of Maranhão, CEP: 65500-00, Chapadinha, MA, Brasil
- Programa de Pós-Graduação em Ciências da Saúde, Universidade Federal do Maranhão, CEP: 65080-805, São Luís, MA, Brasil
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