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Perinet LC, Mutebi JP, Powers AM, Lutwama JJ, Mossel EC. Yata Virus (Family Rhabdoviridae, Genus Ephemerovirus) Isolation from Mosquitoes from Uganda, the First Reported Isolation since 1969. Diseases 2023; 11:diseases11010021. [PMID: 36810535 PMCID: PMC9944095 DOI: 10.3390/diseases11010021] [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: 12/18/2022] [Revised: 01/16/2023] [Accepted: 01/19/2023] [Indexed: 01/31/2023] Open
Abstract
As a part of a systematic study of mosquitoes and associated viruses in Uganda, a virus was isolated from a pool of Mansonia uniformis collected in July 2017, in the Kitgum District of northern Uganda. Sequence analysis determined that the virus is Yata virus (YATAV; Ephemerovirus yata; family Rhabdoviridae). The only previous reported isolation of YATAV was in 1969 in Birao, Central African Republic, also from Ma. uniformis mosquitoes. The current sequence is over 99% identical at the nucleotide level to the original isolate, indicating a high level of YATAV genomic stability.
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Affiliation(s)
- Lara C. Perinet
- Division of Vector-Borne Diseases, US Centers for Disease Control and Prevention, Fort Collins, CO 80521, USA
| | - John-Paul Mutebi
- Division of Vector-Borne Diseases, US Centers for Disease Control and Prevention, Fort Collins, CO 80521, USA
| | - Ann M. Powers
- Division of Vector-Borne Diseases, US Centers for Disease Control and Prevention, Fort Collins, CO 80521, USA
| | - Julius J. Lutwama
- Department of Arbovirology, Emerging, and Re-emerging Diseases, Uganda Virus Research Institute, Entebbe, Uganda
| | - Eric C. Mossel
- Division of Vector-Borne Diseases, US Centers for Disease Control and Prevention, Fort Collins, CO 80521, USA
- Correspondence:
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Jansen van Vuren P, Parry R, Khromykh AA, Paweska JT. A 1958 Isolate of Kedougou Virus (KEDV) from Ndumu, South Africa, Expands the Geographic and Temporal Range of KEDV in Africa. Viruses 2021; 13:v13071368. [PMID: 34372574 PMCID: PMC8309962 DOI: 10.3390/v13071368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 06/17/2021] [Accepted: 06/21/2021] [Indexed: 11/16/2022] Open
Abstract
The mosquito-borne flavivirus, Kedougou virus (KEDV), first isolated in Senegal in 1972, is genetically related to dengue, Zika (ZIKV) and Spondweni viruses (SPOV). Serological surveillance studies in Senegal and isolation of KEDV in the Central African Republic indicate occurrence of KEDV infections in humans, but to date, no disease has been reported. Here, we assembled the coding-complete genome of a 1958 isolate of KEDV from a pool of Aedes circumluteolus mosquitoes collected in Ndumu, KwaZulu-Natal, South Africa. The AR1071 Ndumu KEDV isolate bears 80.51% pairwise nucleotide identity and 93.34% amino acid identity with the prototype DakAar-D1470 strain and was co-isolated with SPOV through intracerebral inoculation of suckling mice and passage on VeroE6 cells. This historical isolate expands the known geographic and temporal range of this relatively unknown flavivirus, aiding future temporal phylogenetic calibration and diagnostic assay refinement.
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Affiliation(s)
- Petrus Jansen van Vuren
- Australian Centre for Disease Preparedness, CSIRO Health & Biosecurity, Private Bag 24, Geelong, VIC 3220, Australia
- Correspondence: ; Tel.: +613-5227-5700
| | - Rhys Parry
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia; (R.P.); (A.A.K.)
| | - Alexander A. Khromykh
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia; (R.P.); (A.A.K.)
- Australian Infectious Diseases Research Centre, Global Virus Network Centre of Excellence, Brisbane, QLD 4029, Australia
| | - Janusz T. Paweska
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg 2131, South Africa;
- Centre for Viral Zoonoses, Department of Medical Virology, Faculty of Health Sciences, University of Pretoria, Pretoria 0001, South Africa
- Faculty of Health Sciences, School of Pathology, University of Witwatersrand, Johannesburg 2050, South Africa
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3
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Orsborne J, Furuya-Kanamori L, Jeffries CL, Kristan M, Mohammed AR, Afrane YA, O'Reilly K, Massad E, Drakeley C, Walker T, Yakob L. Investigating the blood-host plasticity and dispersal of Anopheles coluzzii using a novel field-based methodology. Parasit Vectors 2019; 12:143. [PMID: 30909960 PMCID: PMC6434891 DOI: 10.1186/s13071-019-3401-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 03/15/2019] [Indexed: 11/10/2022] Open
Abstract
Background The biting behaviour and dispersal of insect vectors in the field underlies the transmission of many diseases. Here, a novel collection methodology coupled with the molecular analysis of blood-meal sources and digestion rates is introduced with the aim of aiding the understanding of two critical and relatively understudied mosquito behaviours: plasticity in blood-host choice and vector dispersal. Results A collection strategy utilising a transect of mosquito traps placed at 50 m intervals allowed the collection of blood-fed Anopheles coluzzii from a malaria-endemic village of southern Ghana where human host availability ranged from zero (a cattle pen), increasing until humans were the dominant host choice (the middle of the village). Blood-meal analysis using PCR showed statistically significant variation in blood-meal origins for mosquitoes collected across the 250 m transect: with decreasing trend in Bovine Blood Index (OR = 0.60 95% CI: 0.49–0.73, P < 0.01) and correspondingly, an increasing trend in Human Blood Index (OR = 1.50 95% CI: 1.05–2.16, P = 0.028) as the transect approached the village. Using qPCR, the host DNA remaining in the blood meal was quantified for field-caught mosquitoes and calibrated according to timed blood digestion in colony mosquitoes. Time since blood meal was consumed and the corresponding distance the vector was caught from its blood-host allowed the estimation of An. coluzzii dispersal rates. Within 7 hours of feeding, mosquitoes typically remained within 50 m of their blood-host but at 60 hours they had dispersed up to 250 m. Conclusions Using this methodology the remarkably small spatial scale at which An. coluzzii blood-host choice can change was demonstrated. In addition, conducting qPCR on host blood from field-caught mosquitoes and calibrating with timed experiments with colonised mosquitoes presents a novel methodology for investigating the dispersal behaviour of vectors. Future adaptations to this novel method to make it broadly applicable to other types of setting are also discussed.
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Affiliation(s)
- James Orsborne
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Luis Furuya-Kanamori
- Department of Population Medicine, College of Medicine, Qatar University, Doha, Qatar.,Research School of Population Health, College of Health and Medicine, Australian National University, Canberra, Australia
| | - Claire L Jeffries
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Mojca Kristan
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Abdul Rahim Mohammed
- Department of Medical Microbiology, College of Health Sciences, University of Ghana, Korle Bu, Accra, Ghana
| | - Yaw A Afrane
- Department of Medical Microbiology, College of Health Sciences, University of Ghana, Korle Bu, Accra, Ghana
| | - Kathleen O'Reilly
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Eduardo Massad
- School of Applied Mathematics, Fundacao Getulio Vargas, Rio de Janeiro, Brazil
| | - Chris Drakeley
- Department of Immunology & Infection, London School of Hygiene & Tropical Medicine, London, UK
| | - Thomas Walker
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Laith Yakob
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK.
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Orsborne J, Furuya-Kanamori L, Jeffries CL, Kristan M, Mohammed AR, Afrane YA, O'Reilly K, Massad E, Drakeley C, Walker T, Yakob L. Using the human blood index to investigate host biting plasticity: a systematic review and meta-regression of the three major African malaria vectors. Malar J 2018; 17:479. [PMID: 30563533 PMCID: PMC6299493 DOI: 10.1186/s12936-018-2632-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 12/14/2018] [Indexed: 12/17/2022] Open
Abstract
Background The proportion of mosquito blood-meals that are of human origin, referred to as the ‘human blood index’ or HBI, is a key determinant of malaria transmission. Methods A systematic review was conducted followed by meta-regression of the HBI for the major African malaria vectors. Results Evidence is presented for higher HBI among Anopheles gambiae (M/S forms and Anopheles coluzzii/An. gambiae sensu stricto are not distinguished for most studies and, therefore, combined) as well as Anopheles funestus when compared with Anopheles arabiensis (prevalence odds ratio adjusted for collection location [i.e. indoor or outdoor]: 1.62; 95% CI 1.09–2.42; 1.84; 95% CI 1.35–2.52, respectively). This finding is in keeping with the entomological literature which describes An. arabiensis to be more zoophagic than the other major African vectors. However, analysis also revealed that HBI was more associated with location of mosquito captures (R2 = 0.29) than with mosquito (sibling) species (R2 = 0.11). Conclusions These findings call into question the appropriateness of current methods of assessing host preferences among disease vectors and have important implications for strategizing vector control. Electronic supplementary material The online version of this article (10.1186/s12936-018-2632-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- James Orsborne
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Luis Furuya-Kanamori
- Department of Population Medicine, College of Medicine, Qatar University, Doha, Qatar
| | - Claire L Jeffries
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Mojca Kristan
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Abdul Rahim Mohammed
- Department of Medical Microbiology, College of Health Sciences, University of Ghana, Korle Bu, Accra, Ghana
| | - Yaw A Afrane
- Department of Medical Microbiology, College of Health Sciences, University of Ghana, Korle Bu, Accra, Ghana
| | - Kathleen O'Reilly
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Eduardo Massad
- School of Applied Mathematics, Fundacao Getulio Vargas, Rio de Janeiro, Brazil
| | - Chris Drakeley
- Department of Immunology & Infection, London School of Hygiene & Tropical Medicine, London, UK
| | - Thomas Walker
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Laith Yakob
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK.
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5
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Amvongo-Adjia N, Wirsiy EL, Riveron JM, Chounna Ndongmo WP, Enyong PA, Njiokou F, Wondji CS, Wanji S. Bionomics and vectorial role of anophelines in wetlands along the volcanic chain of Cameroon. Parasit Vectors 2018; 11:471. [PMID: 30107815 PMCID: PMC6092805 DOI: 10.1186/s13071-018-3041-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 07/30/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The epidemiological profiles of vector-borne diseases, such as malaria, are strongly associated with landscape components. The reduction of malaria burden in endemic and epidemic regions mainly depends on knowledge of the malaria-transmitting mosquito species, populations and behavioural characteristics, as well as malaria exposure risks. This work aimed at carrying out a holistic study in order to characterise Anopheles species in relation to human malaria in seven wetlands along the lower section of the volcanic chain of Cameroon. RESULTS Eight malaria vectors: Anopheles arabiensis, An. coluzzii, An. funestus (s.s.), An. gambiae, An. hancocki, An. melas, An. nili and An. ziemanni, were found biting humans. Anopheles gambiae was widespread; however, it played a secondary role in the Ndop plain where An. ziemmani was the primary vector species (79.2%). Anophelines were more exophagic (73.6%) than endophagic (26.4%), showing a marked nocturnal activity (22:00-4:00 h) for An. coluzzii and An. gambiae while An. funestus (s.s.) was mostly caught between 1:00 and 6:00 h and An. ziemanni having an early evening biting behaviour (18:00-00:00 h). Female Anopheles were mostly observed to have relative high parity rates (≥ 70%), with the exception of the Meanja site where species parity varies from 46 to 55%. Overall, the transmission level was low with entomological inoculation rates estimated to 0.7 infected bites per person per month (ib/p/mth) in Tiko and Ndop, 1.4 ib/p/mth in Mamfe and 2.24 ib/p/mth in Santchou. CONCLUSIONS The present study represents detailed Anopheles vector characterisation from an understudied area along the volcanic chain of Cameroon with endemic malaria transmission. The significant differences in bionomics and Anopheles species distribution within the studied wetlands, highlights the importance of providing baseline data and an opportunity to assess the outcome of ongoing malaria control interventions in the country.
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Affiliation(s)
- Nathalie Amvongo-Adjia
- Parasitology and Ecology Laboratory, Animal Biology and Physiology Department, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon. .,Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon. .,Centre for Medical Research, Institute of Medical Research and Medicinal Plants Studies (IMPM), Yaoundé, Cameroon.
| | - Emmanuela L Wirsiy
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasite and Vector Biology Research Unit (PAVBRU), Microbiology and Parasitology Department, University of Buea, Buea, Cameroon
| | - Jacob M Riveron
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Winston P Chounna Ndongmo
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasite and Vector Biology Research Unit (PAVBRU), Microbiology and Parasitology Department, University of Buea, Buea, Cameroon
| | - Peter A Enyong
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon.,Parasite and Vector Biology Research Unit (PAVBRU), Microbiology and Parasitology Department, University of Buea, Buea, Cameroon
| | - Flobert Njiokou
- Parasitology and Ecology Laboratory, Animal Biology and Physiology Department, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon.,Centre for Research in Infectious Diseases (CRID), LSTM Research Unit, Yaoundé, Cameroon
| | - Charles S Wondji
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK.,Centre for Research in Infectious Diseases (CRID), LSTM Research Unit, Yaoundé, Cameroon
| | - Samuel Wanji
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon. .,Parasite and Vector Biology Research Unit (PAVBRU), Microbiology and Parasitology Department, University of Buea, Buea, Cameroon.
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6
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Reeves LE, Holderman CJ, Blosser EM, Gillett-Kaufman JL, Kawahara AY, Kaufman PE, Burkett-Cadena ND. Identification of Uranotaenia sapphirina as a specialist of annelids broadens known mosquito host use patterns. Commun Biol 2018; 1:92. [PMID: 30271973 PMCID: PMC6123777 DOI: 10.1038/s42003-018-0096-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 06/03/2018] [Indexed: 12/21/2022] Open
Abstract
Feeding upon vertebrate blood by mosquitoes permits transmission of diverse pathogens, including viruses, protozoa, and nematodes. Despite over a century of intensive study, no mosquito species is known to specialize on non-vertebrate hosts. Using molecular analyses and field observations, we provide the first evidence, to our knowledge, that a mosquito, Uranotaenia sapphirina, specializes on annelid hosts (earthworms and leeches) while its sympatric congener, Uranotaenia lowii, feeds only on anurans (frogs and toads). Our results demonstrate that Ur. sapphirina feeds on annelid hosts (100% of identified blood meals; n = 72; collected throughout Florida), findings that are supported by field observations of these mosquitoes feeding on Sparganophilus worms and freshwater leeches. These findings indicate that adult mosquitoes utilize a much broader range of host taxa than previously recognized, with implications for epidemiology and the evolution of host use patterns in mosquitoes.
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Affiliation(s)
- Lawrence E Reeves
- Entomology and Nematology Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, 32611, USA.
- Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, FL, 32962, USA.
| | - Chris J Holderman
- Entomology and Nematology Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, 32611, USA
| | - Erik M Blosser
- Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, FL, 32962, USA
| | - Jennifer L Gillett-Kaufman
- Entomology and Nematology Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, 32611, USA
| | - Akito Y Kawahara
- Florida Museum of Natural History, University of Florida, Gainesville, FL, 32611, USA
| | - Phillip E Kaufman
- Entomology and Nematology Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, 32611, USA
| | - Nathan D Burkett-Cadena
- Florida Medical Entomology Laboratory, Institute of Food and Agricultural Sciences, University of Florida, Vero Beach, FL, 32962, USA
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Evans MV, Dallas TA, Han BA, Murdock CC, Drake JM. Data-driven identification of potential Zika virus vectors. eLife 2017; 6:e22053. [PMID: 28244371 PMCID: PMC5342824 DOI: 10.7554/elife.22053] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 02/13/2017] [Indexed: 11/13/2022] Open
Abstract
Zika is an emerging virus whose rapid spread is of great public health concern. Knowledge about transmission remains incomplete, especially concerning potential transmission in geographic areas in which it has not yet been introduced. To identify unknown vectors of Zika, we developed a data-driven model linking vector species and the Zika virus via vector-virus trait combinations that confer a propensity toward associations in an ecological network connecting flaviviruses and their mosquito vectors. Our model predicts that thirty-five species may be able to transmit the virus, seven of which are found in the continental United States, including Culex quinquefasciatus and Cx. pipiens. We suggest that empirical studies prioritize these species to confirm predictions of vector competence, enabling the correct identification of populations at risk for transmission within the United States.
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Affiliation(s)
- Michelle V Evans
- Odum School of Ecology, University of Georgia, Athens, United States
- Center for the Ecology of Infectious Diseases, University of Georgia, Athens, United States
| | - Tad A Dallas
- Odum School of Ecology, University of Georgia, Athens, United States
- Department of Environmental Science and Policy, University of California-Davis, Davis, United States
| | - Barbara A Han
- Cary Institute of Ecosystem Studies, Millbrook, United States
| | - Courtney C Murdock
- Odum School of Ecology, University of Georgia, Athens, United States
- Center for the Ecology of Infectious Diseases, University of Georgia, Athens, United States
- Department of Infectious Disease, University of Georgia, Athens, United States
- Center for Tropical Emerging Global Diseases, University of Georgia, Athens, United States
- Center for Vaccines and Immunology, University of Georgia, Athens, United States
- River Basin Center, University of Georgia, Athens, United States
| | - John M Drake
- Odum School of Ecology, University of Georgia, Athens, United States
- Center for the Ecology of Infectious Diseases, University of Georgia, Athens, United States
- River Basin Center, University of Georgia, Athens, United States
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Maia MF, Kreppel K, Mbeyela E, Roman D, Mayagaya V, Lobo NF, Ross A, Moore SJ. A crossover study to evaluate the diversion of malaria vectors in a community with incomplete coverage of spatial repellents in the Kilombero Valley, Tanzania. Parasit Vectors 2016; 9:451. [PMID: 27527601 PMCID: PMC4986272 DOI: 10.1186/s13071-016-1738-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 08/03/2016] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Malaria elimination is unlikely to occur if vector control efforts focus entirely on transmission occurring indoors without addressing vectors that bite outdoors and outside sleeping hours. Additional control tools such as spatial repellents may provide the personal protection required to fill this gap. However, since repellents do not kill mosquitoes it is unclear if vectors will be diverted from households that use spatial repellents to those that do not. METHODS A crossover study was performed over 24 weeks in Kilombero, Tanzania. The density of resting and blood-engorged mosquitoes and human blood index (HBI) of malaria vector species per household was measured among 90 households using or not using 0.03 % transfluthrin coils burned outdoors under three coverage scenarios: (i) no coverage (blank coils); (ii) complete coverage of repellent coils; and (iii) incomplete coverage of repellent and blank coils. Mosquitoes were collected three days a week for 24 weeks from the inside and outside of all participating households using mosquito aspirators. Paired indoor and outdoor human landing collections were performed in three random households for six consecutive nights to confirm repellent efficacy of the coils and local vector biting times. RESULTS The main vectors were Anopheles arabiensis and Anopheles funestus (sensu stricto), which fed outdoors, outside sleeping hours, on humans as well as animals. Anopheles arabiensis landings were reduced by 80 % by the spatial repellent although household densities were not reduced. The HBI for An. arabiensis was significantly higher among households without repellents in the incomplete coverage scenario compared to houses in the no coverage scenario (Odds ratio 1.71; 95 % CI: 1.04-2.83; P = 0.03). This indicated that An. arabiensis mosquitoes seeking a human blood meal were diverted from repellent users to non-users. The repellent coils did not affect An. funestus densities or HBI. CONCLUSIONS Substantial malaria vector activity is occurring outside sleeping hours in the Kilombero valley. Repellent coils provided some protection against local An. arabiensis but did not protect against local (and potentially pyrethroid-resistant) An. funestus. Pyrethroid-based spatial repellents may offer a degree of personal protection, however the overall public health benefit is doubtful and potentially iniquitous as their use may divert malaria vectors to those who do not use them.
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Affiliation(s)
- Marta Ferreira Maia
- Swiss Tropical and Public Health Institute, Socinstr. 57, Basel, CH-4002 Switzerland
- University of Basel, St. Petersplatz 1, CH-4002 Basel, Switzerland
- Ifakara Health Institute, P.O. Box 74, Bagamoyo, Pwani United Republic of Tanzania
| | - Katharina Kreppel
- Ifakara Health Institute, P.O. Box 74, Bagamoyo, Pwani United Republic of Tanzania
- University of Glasgow, Institute of Biodiversity Animal Health and Comparative Medicine, Glasgow, G12 8QQ UK
| | - Edgar Mbeyela
- Ifakara Health Institute, P.O. Box 74, Bagamoyo, Pwani United Republic of Tanzania
| | - Deogratius Roman
- Ifakara Health Institute, P.O. Box 74, Bagamoyo, Pwani United Republic of Tanzania
| | - Valeriana Mayagaya
- Ifakara Health Institute, P.O. Box 74, Bagamoyo, Pwani United Republic of Tanzania
| | - Neil F. Lobo
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Amanda Ross
- Swiss Tropical and Public Health Institute, Socinstr. 57, Basel, CH-4002 Switzerland
- University of Basel, St. Petersplatz 1, CH-4002 Basel, Switzerland
| | - Sarah Jane Moore
- Swiss Tropical and Public Health Institute, Socinstr. 57, Basel, CH-4002 Switzerland
- University of Basel, St. Petersplatz 1, CH-4002 Basel, Switzerland
- Ifakara Health Institute, P.O. Box 74, Bagamoyo, Pwani United Republic of Tanzania
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9
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Tchouassi DP, Okiro ROK, Sang R, Cohnstaedt LW, McVey DS, Torto B. Mosquito host choices on livestock amplifiers of Rift Valley fever virus in Kenya. Parasit Vectors 2016; 9:184. [PMID: 27036889 PMCID: PMC4815150 DOI: 10.1186/s13071-016-1473-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 03/23/2016] [Indexed: 11/29/2022] Open
Abstract
Background Animal hosts may vary in their attraction and acceptability as components of the host location process for assessing preference, and biting rates of vectors and risk of exposure to pathogens. However, these parameters remain poorly understood for mosquito vectors of the Rift Valley fever (RVF), an arboviral disease, and for a community of mosquitoes. Methods Using three known livestock amplifiers of RVF virus including sheep, goat and cattle as bait in enclosure traps, we investigated the host-feeding patterns for a community of mosquitoes in Naivasha, an endemic area of Rift Valley fever (RVF), in a longitudinal study for six months (June–November 2015). We estimated the incidence rate ratios (IRR) where mosquitoes chose cow over the other livestock hosts by comparing their attraction (total number collected) and engorgement rate (proportion freshly blood-fed) on these hosts. Results Overall, significant differences were observed in host preference parameters for attraction (F2,15 = 4.1314, P = 0.037) and engorgement (F2,15 = 6.24, P = 0.01) with cow consistently attracting about 3-fold as many mosquitoes as those engorged on sheep (attraction: IRR = 2.9, 95 % CI 1.24–7.96; engorgement: IRR = 3.2, 95 % CI = 1.38–7.38) or goat (attraction: IRR = 2.7, 95 % CI 1.18–7.16; engorgement: IRR = 3.28, 95 % CI 1.47–7.53). However, there was no difference between the attraction elicited by sheep and goat (IRR = 1.08; 95 % CI 0.35–3.33 or engorgement rate (IRR = 0.96, 95 % CI 0.36–2.57). Conclusion Despite the overall attractive pattern to feed preferentially on cows, the engorgement rate was clearly independent of the number attracted for certain mosquito species, notably among the flood water Aedes spp., largely incriminated previously as primary vectors of RVF. Our findings suggest that insecticide treated cattle (ITC) can be exploited in enclosure traps as contact bait in the monitoring and control of disease-causing mosquitoes in RVF endemic areas.
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Affiliation(s)
- David P Tchouassi
- International Centre of Insect Physiology and Ecology, P. O. Box 30772-00100, Nairobi, Kenya.
| | - Robinson O K Okiro
- International Centre of Insect Physiology and Ecology, P. O. Box 30772-00100, Nairobi, Kenya
| | - Rosemary Sang
- International Centre of Insect Physiology and Ecology, P. O. Box 30772-00100, Nairobi, Kenya.,Centre for Virus Research, Kenya Medical Research Institute (KEMRI), P.O. Box 54840-00200, Nairobi, Kenya
| | - Lee W Cohnstaedt
- United States Department for Agriculture - Agricultural Research Station (USDA-ARS), Arthropod-Borne Animal Disease Research Unit, Center for Grain and Animal Health Research, 515 College Ave, Manhattan, KS 66502, KS, USA
| | - David Scott McVey
- United States Department for Agriculture - Agricultural Research Station (USDA-ARS), Arthropod-Borne Animal Disease Research Unit, Center for Grain and Animal Health Research, 515 College Ave, Manhattan, KS 66502, KS, USA
| | - Baldwyn Torto
- International Centre of Insect Physiology and Ecology, P. O. Box 30772-00100, Nairobi, Kenya
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Wijers DJB, Kiilu G. Bancroftian filariasis in Kenya. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2016. [DOI: 10.1080/00034983.1977.11687195] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Maia MF, Abonuusum A, Lorenz LM, Clausen PH, Bauer B, Garms R, Kruppa T. The effect of deltamethrin-treated net fencing around cattle enclosures on outdoor-biting mosquitoes in Kumasi, Ghana. PLoS One 2012; 7:e45794. [PMID: 23029245 PMCID: PMC3446911 DOI: 10.1371/journal.pone.0045794] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 08/24/2012] [Indexed: 12/03/2022] Open
Abstract
Classic vector control strategies target mosquitoes indoors as the main transmitters of malaria are indoor-biting and -resting mosquitoes. However, the intensive use of insecticide-treated bed-nets (ITNs) and indoor residual spraying have put selective pressure on mosquitoes to adapt in order to obtain human blood meals. Thus, early-evening and outdoor vector activity is becoming an increasing concern. This study assessed the effect of a deltamethrin-treated net (100 mg/m(2)) attached to a one-meter high fence around outdoor cattle enclosures on the number of mosquitoes landing on humans. Mosquitoes were collected from four cattle enclosures: Pen A - with cattle and no net; B - with cattle and protected by an untreated net; C - with cattle and protected by a deltamethrin-treated net; D - no cattle and no net. A total of 3217 culicines and 1017 anophelines were collected, of which 388 were Anopheles gambiae and 629 An. ziemanni. In the absence of cattle nearly 3 times more An. gambiae (p<0.0001) landed on humans. The deltamethrin-treated net significantly reduced (nearly three-fold, p<0.0001) culicine landings inside enclosures. The sporozoite rate of the zoophilic An. ziemanni, known to be a secondary malaria vector, was as high as that of the most competent vector An. gambiae; raising the potential of zoophilic species as secondary malaria vectors. After deployment of the ITNs a deltamethrin persistence of 9 months was observed despite exposure to African weather conditions. The outdoor use of ITNs resulted in a significant reduction of host-seeking culicines inside enclosures. Further studies investigating the effectiveness and spatial repellence of ITNs around other outdoor sites, such as bars and cooking areas, as well as their direct effect on vector-borne disease transmission are needed to evaluate its potential as an appropriate outdoor vector control tool for rural Africa.
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Affiliation(s)
- Marta Ferreira Maia
- London School of Hygiene and Tropical Medicine, Department of Disease Control, London, UK.
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Farajollahi A, Fonseca DM, Kramer LD, Kilpatrick AM. "Bird biting" mosquitoes and human disease: a review of the role of Culex pipiens complex mosquitoes in epidemiology. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2011; 11:1577-85. [PMID: 21875691 PMCID: PMC3190018 DOI: 10.1016/j.meegid.2011.08.013] [Citation(s) in RCA: 367] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 08/15/2011] [Accepted: 08/16/2011] [Indexed: 11/27/2022]
Abstract
The transmission of vector-borne pathogens is greatly influenced by the ecology of their vector, which is in turn shaped by genetic ancestry, the environment, and the hosts that are fed on. One group of vectors, the mosquitoes in the Culex pipiens complex, play key roles in the transmission of a range of pathogens including several viruses such as West Nile and St. Louis encephalitis viruses, avian malaria (Plasmodium spp.), and filarial worms. The Cx. pipiens complex includes Culex pipiens pipiens with two forms, pipiens and molestus, Culex pipiens pallens, Culex quinquefasciatus, Culex australicus, and Culex globocoxitus. While several members of the complex have limited geographic distributions, Cx. pipienspipiens and Cx. quinquefasciatus are found in all known urban and sub-urban temperate and tropical regions, respectively, across the world, where they are often principal disease vectors. In addition, hybrids are common in areas of overlap. Although gaps in our knowledge still remain, the advent of genetic tools has greatly enhanced our understanding of the history of speciation, domestication, dispersal, and hybridization. We review the taxonomy, genetics, evolution, behavior, and ecology of members of the Cx. pipiens complex and their role in the transmission of medically important pathogens. The adaptation of Cx. pipiens complex mosquitoes to human-altered environments led to their global distribution through dispersal via humans and, combined with their mixed feeding patterns on birds and mammals (including humans), increased the transmission of several avian pathogens to humans. We highlight several unanswered questions that will increase our ability to control diseases transmitted by these mosquitoes.
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Affiliation(s)
- Ary Farajollahi
- Rutgers University, Center for Vector Biology, New Brunswick, New Jersey
| | - Dina M. Fonseca
- Rutgers University, Center for Vector Biology, New Brunswick, New Jersey
| | - Laura D. Kramer
- Wadsworth Center, New York State Department of Health, Slingerlands, New York, and State University of New York at Albany, Albany, New York
| | - A. Marm Kilpatrick
- Dept. Ecology and Evolutionary Biology, University of California, Santa Cruz, California
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Abstract
Usutu virus (USUV) was discovered in South Africa in 1959. Since then, it has been reported in several African countries including Senegal, Central African Republic, Nigeria, Uganda, Burkina Faso, Cote d'Ivoire, and Morocco. In 2001, USUV has been identified for the first time outside of Africa, namely in Europe, where it caused a significant mortality among blackbirds in Vienna, Austria. In 2009, the first two human cases of USUV infection in Europe have been reported in Italy, causing encephalitis in immunocompromised patients. The host range in Africa includes mainly Culex mosquitoes, birds, and also humans with one benign and one severe case. Given its role as a potential human pathogen and the similar appearance compared with other emerging arboviruses, it is essential to investigate the natural history and ecology of USUV in Africa. In this regard, we review the emergence of USUV in Africa, summarizing data about isolations, host range, and potential vectors, which should help to improve our understanding of the factors underlying the circulation of USUV in Europe and Africa.
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Affiliation(s)
- Birgit Nikolay
- Unité des Arbovirus et Virus de Fièvres Hémorragiques, Institut Pasteur de Dakar, Dakar, Senegal
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Chandler J. The use of light traps to study flight activity and seasonal abundance of mosquitoes of medical importance on the Kano Plain, Kenya. ACTA ACUST UNITED AC 2008. [DOI: 10.1080/00207237708737314] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Blood-feeding patterns of Culex quinquefasciatus and other culicines and implications for disease transmission in Mwea rice scheme, Kenya. Parasitol Res 2008; 102:1329-35. [PMID: 18297310 DOI: 10.1007/s00436-008-0914-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Accepted: 01/29/2008] [Indexed: 10/22/2022]
Abstract
Studies were conducted in Mwea Rice Scheme, Kenya during the period April 2005 and January 2007 to determine the host-feeding pattern of culicine mosquitoes. Mosquitoes were collected indoors and outdoors and tested for human, bovine, goat, and donkey blood meals by an Enzyme-Linked Immunosorbent Assay. A total of 1,714 blood-engorged samples comprising Culex quinquefasciatus Say (96.1%), Culex annulioris Theobald (1.8%), Culex poicilipes Theobald (0.9%), Aedes cuminsi Theobald (1.0%), Aedes taylori Edwards (0.1%), and Mansonia africana Theobald (0.1%) were tested. Except for A. taylori, in which the single blood meal tested was of bovine origin, the other species fed mostly on both bovine (range 73.3-100%) and goats (range 50-100%). Donkeys were also common hosts for all species (range 19.4-23.5%) except A. taylori and M. africana. C. quinquefasciatus was the only species containing human blood meals (0.04), and indoor collected populations of this species had significantly higher frequency of human blood meals (9.8%) compared with outdoor-collected populations (3.0%). Mixed blood feeding was dominant among culicine species comprising 50.0%, 73.3%, 73.5%, 80.6%, and 94.1% of the samples for M. africana, C. poicilipes, C. quinquefasciatus, C. annulioris, and A. cuminsi, respectively. Ten mixed blood meal combinations including a mixture of all the four hosts were observed in C. quinquefasciatus, compared to one blood meal combination for M. Africana, and two combinations for C. poicilipes, C. annulioris, and A. cuminsi. Mixed bovine and goat blood meal was the most common combination among the five culicine species followed by a mixture of donkey, bovine, and goat blood meals. We conclude that culicine species in Mwea are least likely to be vectors of lymphatic filariasis due to their high "preference" for livestock over human hosts, but they present an increased risk for arbovirus transmission particularly Rift Valley Fever virus, in which domestic animals serve as amplification hosts.
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Moffett A, Shackelford N, Sarkar S. Malaria in Africa: vector species' niche models and relative risk maps. PLoS One 2007; 2:e824. [PMID: 17786196 PMCID: PMC1950570 DOI: 10.1371/journal.pone.0000824] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Accepted: 08/06/2007] [Indexed: 11/19/2022] Open
Abstract
A central theoretical goal of epidemiology is the construction of spatial models of disease prevalence and risk, including maps for the potential spread of infectious disease. We provide three continent-wide maps representing the relative risk of malaria in Africa based on ecological niche models of vector species and risk analysis at a spatial resolution of 1 arc-minute (9 185 275 cells of approximately 4 sq km). Using a maximum entropy method we construct niche models for 10 malaria vector species based on species occurrence records since 1980, 19 climatic variables, altitude, and land cover data (in 14 classes). For seven vectors (Anopheles coustani, A. funestus, A. melas, A. merus, A. moucheti, A. nili, and A. paludis) these are the first published niche models. We predict that Central Africa has poor habitat for both A. arabiensis and A. gambiae, and that A. quadriannulatus and A. arabiensis have restricted habitats in Southern Africa as claimed by field experts in criticism of previous models. The results of the niche models are incorporated into three relative risk models which assume different ecological interactions between vector species. The “additive” model assumes no interaction; the “minimax” model assumes maximum relative risk due to any vector in a cell; and the “competitive exclusion” model assumes the relative risk that arises from the most suitable vector for a cell. All models include variable anthrophilicity of vectors and spatial variation in human population density. Relative risk maps are produced from these models. All models predict that human population density is the critical factor determining malaria risk. Our method of constructing relative risk maps is equally general. We discuss the limits of the relative risk maps reported here, and the additional data that are required for their improvement. The protocol developed here can be used for any other vector-borne disease.
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Affiliation(s)
- Alexander Moffett
- Section of Integrative Biology, University of Texas at Austin, Austin, Texas, United States of America
| | - Nancy Shackelford
- Section of Integrative Biology, University of Texas at Austin, Austin, Texas, United States of America
| | - Sahotra Sarkar
- Section of Integrative Biology, University of Texas at Austin, Austin, Texas, United States of America
- * To whom correspondence should be addressed. E-mail:
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Onapa AW, Pedersen EM, Reimert CM, Simonsen PE. A role for Mansonia uniformis mosquitoes in the transmission of lymphatic filariasis in Uganda? Acta Trop 2007; 101:159-68. [PMID: 17316535 DOI: 10.1016/j.actatropica.2007.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2005] [Revised: 11/27/2006] [Accepted: 12/08/2006] [Indexed: 11/21/2022]
Abstract
The possible role of Mansonia uniformis mosquitoes in the transmission of lymphatic filariasis was assessed in an endemic area of Uganda, by examining their diurnal biting cycle, host preference and ability to support the development of experimental and natural Wuchereria bancrofti infections. Anopheles gambiae s.l. served as controls. Human landing catches revealed that outdoor biting peaked early in the evening (19:00-20:00h), while indoor biting peaked around midnight (23:00-24:00h). By far the majority of indoor collected M. uniformis had derived their blood meals from humans. Both biting and feeding behaviour were therefore compatible with a potential for transmission. In experimentally fed M. uniformis (total of 1915), the microfilariae were seen to ex-sheath and to start migration, but the L1s accumulated in the thorax and only few developed further. In dissections from Day 11 onwards, 4.6% (43/932) of M. uniformis had L2 larvae and 0.7% (7/932) had L3 larvae of W. bancrofti. The corresponding figures for An. gambiae s.l. were 13.4% and 4.6%, respectively. Dissection of wild caught M. uniformis (total of 6823) did not reveal any natural infections with W. bancrofti infective larvae, whereas wild caught An. gambiae s.l. had an infective rate of 1.3%. Other filarial species, and mermithids, were common in M. uniformis. It is concluded that M. uniformis has a limited potential to support development of W. bancrofti to the infective stage, and it does not appear to play a role as a vector under natural conditions.
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Affiliation(s)
- Ambrose W Onapa
- Vector Control Division, Ministry of Health, P.O. Box 1661, Kampala, Uganda
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Samuel PP, Arunachalam N, Hiriyan J, Thenmozhi V, Gajanana A, Satyanarayana K. Host-feeding pattern of Culex quinquefasciatus Say and Mansonia annulifera (Theobald) (Diptera: Culicidae), the major vectors of filariasis in a rural area of south India. JOURNAL OF MEDICAL ENTOMOLOGY 2004; 41:442-446. [PMID: 15185948 DOI: 10.1603/0022-2585-41.3.442] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Culex quinquefasciatus and Mansonia annulifera are abundant in the rural areas of Kuttanadu, Kerala, India. Bloodmeal identification for individuals of these species collected in this region was determined by the agar-gel precipitin test. A total of 2,328 blood smears from Cx. quinquefasciatus (1,148) and Ma. annulifera (1,180) was tested. Results showed that Cx. quinquefasciatus and Ma. annulifera were highly anthropophilic and that human feeding accounted for 74 and 66% of the total bloodmeals tested. Feeding on cattle accounted for only 1.5 and 2.1% of Cx. quinquefasciatus and Ma. annulifera bloodmeals, respectively. This study showed the high anthropophilic feeding rates of Cx. quinquefasciatus and Ma. annulifera collected from an endemic belt of Malayan filariasis, where epidemiological studies revealed the coexistence of Bancroftian and Malayan filariasis.
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Affiliation(s)
- P Philip Samuel
- Centre for Research in Medical Entomology, Indian Council of Medical Research, Tamil Nadu, India
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Gad AM, Farid HA, Ramzy RR, Riad MB, Presley SM, Cope SE, Hassan MM, Hassan AN. Host feeding of mosquitoes (Diptera: Culicidae) associated with the recurrence of Rift Valley fever in Egypt. JOURNAL OF MEDICAL ENTOMOLOGY 1999; 36:709-714. [PMID: 10593070 DOI: 10.1093/jmedent/36.6.709] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In 1993, Rift Valley fever (RVF) virus reappeared in Egypt. We determined the prevalence and feeding patterns of mosquitoes in 5 villages where the virus was active. Of 10 species recovered, Aedes caspius (Pallas), Culex pipiens L., Cx. antennatus (Becker), and Cx. perexiguus Theobald constituted 99% of > 35,000 mosquitoes captured in dry ice-baited CDC light traps. Ae. caspius was most prevalent, except at Nag' El Hagar where it was replaced by Cx. perexiguus. Cx. pipiens ranked 2nd, except at Nag' El Ghuneimiya, where it was replaced by Cx. antennatus. Most blood meals analyzed by an enzyme-linked immunosorbent assay reacted to > or = 1 antiserum. Cx. pipiens was mainly anthropophagic, and therefore may have been the main vector of RVF virus among humans. Ae. caspius feeds were chiefly from humans, bovines, and equines. Cx. antennatus and Cx. perexiguus fed generally on bovines. Mixed blood meals from humans and RVF virus susceptible animals were identified in the predominant mosquitoes. Prevalence and host selection, as well as predicted probability for a blood meal being interrupted, indicated that Ae. caspius may have served as a bridge vector between humans and bovines in 4 of the villages. Cx. perexiguus may have played this role at Nag' El Hagar. Because potential vectors are abundant, susceptible domestic animals are associated closely with humans, and surveillance of imported livestock is not systematic, we conclude that RVF virus sporadically will recur in Egypt.
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Affiliation(s)
- A M Gad
- Research and Training Center on Vectors of Diseases, Ain Shams University, Cairo, Egypt
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Vulule JM, Beach RF, Atieli FK, Roberts JM, Mount DL, Mwangi RW. Reduced susceptibility of Anopheles gambiae to permethrin associated with the use of permethrin-impregnated bednets and curtains in Kenya. MEDICAL AND VETERINARY ENTOMOLOGY 1994; 8:71-75. [PMID: 8161849 DOI: 10.1111/j.1365-2915.1994.tb00389.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Susceptibility of the malaria vector Anopheles gambiae to permethrin decreased following the installation of mosquito nets impregnated with 0.5 g permethrin per square metre in four villages near Kisumu, Kenya. During the first year that permethrin-impregnated bednets and curtains were in place, the exposure time to 50% mortality (LT50) increased 2.5-fold from 13 to 33 min, while the LT50 for An.gambiae was unchanged in two other villages where no intervention measures were used. Two years after permethrin-impregnated mosquito nets were distributed the LT50s for An.gambiae were 28, 28 and 16 min, respectively, in the villages with bednets, curtains and with no such intervention. Using a colony of An.gambiae derived from females collected in the villages using permethrin-impregnated mosquito nets, we lengthened the LT50 from 28 to 41 min in two generations by exposing all females to permethrin-treated papers for 60 min and rearing offspring of the survivors. Permethrin-impregnated bednets and curtains are intended to reduce vectorial capacity. Reduced susceptibility to permethrin could counter this beneficial effect.
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Affiliation(s)
- J M Vulule
- Research Centre, Kenya Medical Research Institute, Nairobi, Kenya
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Reisen WK, Hayes CG, Azra K, Niaz S, Mahmood F, Parveen T, Boreham PF. West Nile virus in Pakistan. II. Entomological studies at Changa Manga National Forest, Punjab Province. Trans R Soc Trop Med Hyg 1982; 76:437-48. [PMID: 6134361 DOI: 10.1016/0035-9203(82)90131-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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Johnson BK, Shockley P, Chanas AC, Squires EJ, Gardner P, Wallace C, Simpson DI, Bowen ET, Platt GS, Way H, Chandler JA, Highton RB, Hill MN. Arbovirus isolations from mosquitoes: Kano Plain, Kenya. Trans R Soc Trop Med Hyg 1977; 71:518-21. [PMID: 24288 DOI: 10.1016/0035-9203(77)90147-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Arbovirus isolation attempts on 324,486 mosquitoes captured over a four-year period on the Kano Plain, Kenya, yielded 15 isolates including Pongola (six strains), Ilesha (three strains), Germiston (two strains), Sindbis (one strain), Barur (one strain) and two viruses which could not be characterized. Mansonia uniformis, Anopheles gambiae and Culex antennatus constituted 70% of the total collection and accounted for all of the isolates except one, which came from Anopheles funestus.
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