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Han S, Miot EF, Liao Y, Somboon P, Harbach RE, Sze-To KM, Tang LTW, Guénard B, Lam TTY. Updated checklist with new records and molecular data for the mosquitoes (Diptera: Culicidae) of Hong Kong. JOURNAL OF MEDICAL ENTOMOLOGY 2024:tjae125. [PMID: 39349390 DOI: 10.1093/jme/tjae125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 08/20/2024] [Accepted: 09/09/2024] [Indexed: 10/02/2024]
Abstract
An extensive mosquito survey was carried out in Hong Kong from September to October 2022, employing a variety of collection methods. Specimens were identified using a combination of morphology and mitochondrial cytochrome C oxidase subunit 1 (COI) barcode sequences. Twenty-nine species, including three new records, i.e., Culex bicornutus (Theobald), Culex cinctellus Edwards, and Lutzia chiangmaiensis Somboon & Harbach, were collected. Phylogenetic analysis of COI sequences of Culex annulus Theobald and Culex vishnui Theobald collected in Hong Kong and elsewhere revealed that the sequences of the two nominal species are genetically very similar and are included in the same clade. Consequently, the synonymy of Cx. annulus with Cx. vishnui is reinstated. Lutzia halifaxii (Theobald) is removed from the list of species in Hong Kong and is replaced with Lutzia vorax Edwards, the identification of which is confirmed in the present study. The record of Culex spiculothorax Bram recorded in Hong Kong is replaced with the senior synonym Culex sasai Kano, Nitahara & Awaya. The occurrence of Anopheles fluviatilis James and Aedes aegypti (Linnaeus) is discussed. Finally, an updated checklist of the mosquitoes of Hong Kong, which now includes 76 species representing 14 genera, is provided, with notation of those species that vector pathogens of human diseases.
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Affiliation(s)
- Shaolin Han
- Centre for Immunology & Infection, Hong Kong SAR, China
- State Key Laboratory of Emerging Infectious Diseases, School of Public Health, The University of Hong Kong, Hong Kong SAR, China
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - Elliott F Miot
- Centre for Immunology & Infection, Hong Kong SAR, China
- State Key Laboratory of Emerging Infectious Diseases, School of Public Health, The University of Hong Kong, Hong Kong SAR, China
- MIVEGEC, Université de Montpellier, IRD, CNRS, 34394 Montpellier, France
| | - Yunshi Liao
- Centre for Immunology & Infection, Hong Kong SAR, China
- State Key Laboratory of Emerging Infectious Diseases, School of Public Health, The University of Hong Kong, Hong Kong SAR, China
| | - Pradya Somboon
- Department of Parasitology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Ralph E Harbach
- Department of Science, Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Ka Mei Sze-To
- Centre for Immunology & Infection, Hong Kong SAR, China
| | | | - Benoit Guénard
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - Tommy Tsan-Yuk Lam
- Centre for Immunology & Infection, Hong Kong SAR, China
- State Key Laboratory of Emerging Infectious Diseases, School of Public Health, The University of Hong Kong, Hong Kong SAR, China
- Laboratory of Data Discovery for Health, Hong Kong SAR, China
- HKU-Pasteur Research Pole, Hong Kong SAR, China
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Sumboh JG, Laryea NA, Otchere J, Ahorlu CS, de Souza DK. Towards Understanding the Microepidemiology of Lymphatic Filariasis at the Community Level in Ghana. Trop Med Infect Dis 2024; 9:107. [PMID: 38787040 PMCID: PMC11125695 DOI: 10.3390/tropicalmed9050107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 04/30/2024] [Accepted: 05/03/2024] [Indexed: 05/25/2024] Open
Abstract
Studies on the distribution of lymphatic filariasis (LF) have mostly focused on reporting prevalence at the community level and distribution at the district levels. Understanding the distribution patterns at community levels may help in designing surveillance strategies. This study aimed to characterize the spatial distribution of LF infections in four hotspot communities in Ghana. The research, involving 252 participants, collected demographic data, mass drug administration (MDA) information, household GPS coordinates, and antigen detection test results. The LF prevalence varied significantly among the communities, with Asemda having the highest (33.33%) and Mempeasem having the lowest (4.44%). Females had lower odds of infection than males (OR = 2.67, p = 0.003 CI: 1.39-5.13). Spatial analysis using kernel density, Anselin Local Moran's, Getis-Ord Gi models, Ordinary Least Squares, and Geographic Weighted Regression revealed mixed patterns of spatial autocorrelation. This study identified LF hotspots, indicating clusters of high or low prevalence with some areas showing disparities between MDA coverage and LF positivity rates. Despite these hotspots, the overall distribution of LF appeared random, suggesting the importance of purposeful sampling in surveillance activities. These findings contribute valuable insights into the micro-epidemiology of LF, emphasizing the need for community-specific investigations to understand the factors influencing the effectiveness of MDA programs in controlling filarial infections. The study highlights the importance of refining surveillance strategies based on community-level distribution patterns.
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Affiliation(s)
- Jeffrey Gabriel Sumboh
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra P.O. Box LG 581, Ghana; (J.G.S.); (J.O.)
| | - Nii A. Laryea
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra P.O. Box LG 581, Ghana; (N.A.L.); (C.S.A.)
| | - Joseph Otchere
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra P.O. Box LG 581, Ghana; (J.G.S.); (J.O.)
| | - Collins S. Ahorlu
- Department of Epidemiology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra P.O. Box LG 581, Ghana; (N.A.L.); (C.S.A.)
| | - Dziedzom K. de Souza
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra P.O. Box LG 581, Ghana; (J.G.S.); (J.O.)
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Jacob B, Michael E, Unnasch TR. Community-Directed Vector Control to Accelerate Onchocerciasis Elimination. Pathogens 2024; 13:268. [PMID: 38535611 PMCID: PMC10975871 DOI: 10.3390/pathogens13030268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 03/11/2024] [Accepted: 03/16/2024] [Indexed: 04/01/2024] Open
Abstract
Onchocerciasis, or river blindness, has historically been one of the most important causes of blindness worldwide, and a major cause of socio-economic disruption, particularly in sub-Saharan Africa. Its importance as a cause of morbidity and an impediment to economic development in some of the poorest countries in the world motivated the international community to implement several programs to control or eliminate this scourge. Initially, these involved reducing transmission of the causative agent Onchocerca volvulus through controlling the vector population. When ivermectin was found to be a very effective drug for treating onchocerciasis, the strategy shifted to mass drug administration (MDA) of endemic communities. In some countries, both vector control and ivermectin MDA have been used together. However, traditional vector control methods involve treating rivers in which the black fly vectors breed with insecticides, a process which is expensive, requires trained personnel to administer, and can be ecologically harmful. In this review, we discuss recent research into alternatives to riverine insecticide treatment, which are inexpensive, ecologically less harmful, and can be implemented by the affected communities themselves. These can dramatically reduce vector densities and, when combined with ivermectin MDA, can accelerate the time to elimination when compared to MDA alone.
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Affiliation(s)
| | | | - Thomas R. Unnasch
- Center for Global Health Infectious Disease Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Suite 304, Tampa, FL 33612, USA; (B.J.); (E.M.)
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Coulibaly S, Sawadogo SP, Nikièma AS, Hien AS, Bamogo R, Koala L, Sangaré I, Bougma RW, Koudou B, Fournet F, Ouédraogo GA, Dabiré RK. Assessment of Culicidae collection methods for xenomonitoring lymphatic filariasis in malaria co-infection context in Burkina Faso. PLoS Negl Trop Dis 2024; 18:e0012021. [PMID: 38551982 PMCID: PMC11006119 DOI: 10.1371/journal.pntd.0012021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/10/2024] [Accepted: 02/25/2024] [Indexed: 04/11/2024] Open
Abstract
BACKGROUND Entomological surveillance of lymphatic filariasis and malaria infections play an important role in the decision-making of national programs to control, or eliminate these both diseases. In areas where both diseases prevalence is low, a large number of mosquitoes need to be sampled to determine vectors infection rate. To do this, efficient mosquito collection methods must be used. This study is part in this framework, to assess appropriate mosquito collection methods for lymphatic filariasis xenomonitoring in a coexistence context with malaria in Burkina Faso. METHODOLOGY/PRINCIPAL FINDINGS Mosquito collections were performed between August and September 2018 in four villages (Koulpissi, Seiga, and Péribgan, Saptan), distributed in East and South-West health regions of Burkina Faso. Different collection methods were used: Human Landing Catches (HLC) executed indoor and outdoor, Window Exit-Trap, Double Net Trap (DNT) and Pyrethrum Spray Catches (PSC). Molecular analyses were performed to identify Anopheles gambiae s.l. sibling species and to detect Wuchereria bancrofti and Plasmodium falciparum infection in Anopheles mosquitoes. A total of 3 322 mosquitoes were collected among this, Anopheles gambiae s.l. was the vector caught in largest proportion (63.82%). An. gambiae s.l. sibling species molecular characterization showed that An. gambiae was the dominant specie in all villages. The Human Landing Catches (indoor and outdoor) collected the highest proportion of mosquitoes (between 61.5% and 82.79%). For the sampling vectors infected to W. bancrofti or P. falciparum, PSC, HLC and Window Exit-Trap were found the most effective collection methods. CONCLUSIONS/SIGNIFICANCE This study revealed that HLC indoor and outdoor remained the most effective collection method. Likewise, the results showed the probability to use Window Exit-Trap and PSC collection methods to sample Anopheles infected.
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Affiliation(s)
- Sanata Coulibaly
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso
| | - Simon P. Sawadogo
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso
| | - Achille S. Nikièma
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso
| | - Aristide S. Hien
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso
| | - Rabila Bamogo
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso
| | - Lassane Koala
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso
| | | | - Roland W. Bougma
- Programme National de Lutte contre les Maladies Tropicales Négligées, Ministère de la Santé, Ouagadougou, Burkina Faso
| | - Benjamin Koudou
- Centre Suisse de Recherches Scientifiques, Université Félix-Houphouët-Boigny, Abidjan, Côte d’Ivoire
| | | | | | - Roch K. Dabiré
- Institut de Recherche en Sciences de la Santé (IRSS), Bobo-Dioulasso, Burkina Faso
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Masiyiwa T, Bockarie MJ. Ending lymphatic filariasis and onchocerciasis in Africa: Reasons for hope. Int J Infect Dis 2024; 140:102-103. [PMID: 38280664 DOI: 10.1016/j.ijid.2024.01.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2024] Open
Affiliation(s)
| | - Moses John Bockarie
- College of Medical Sciences, Njala University, Bo Campus, Sierra Leone; International Society for Infectious Diseases.
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Bhuvaneswari A, Shriram AN, Raju KHK, Kumar A. Mosquitoes, Lymphatic Filariasis, and Public Health: A Systematic Review of Anopheles and Aedes Surveillance Strategies. Pathogens 2023; 12:1406. [PMID: 38133290 PMCID: PMC10747758 DOI: 10.3390/pathogens12121406] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 11/06/2023] [Accepted: 11/15/2023] [Indexed: 12/23/2023] Open
Abstract
Lymphatic Filariasis (LF) affects over 120 million people in 72 countries, with sub-periodic filariasis common in the Pacific. Wuchereria bancrofti has three physiological races, each with a unique microfilarial periodicity, and each race is isolated to a specific geographical region. Sub-periodic W. bancrofti is transmitted by various Aedes mosquito species, with Aedes polynesiensis and Aedes samoanus being the primary vectors in Samoa. The Aedes scutellaris and Aedes kochi groups are also important vectors in the South Pacific Islands. Anopheles species are important vectors of filariasis in rural areas of Asia and Africa. The Anopheles gambiae complex, Anopheles funestus, and the Anopheles punctulatus group are the most important vectors of W. bancrofti. These vectors exhibit indoor nocturnal biting behaviour and breed in a variety of habitats, including freshwater, saltwater, and temporary water bodies. Effective vector surveillance is central to LF control and elimination programs. However, the traditional Human Landing Collection (HLC) method, while valuable, poses ethical concerns and risks to collectors. Therefore, this review critically analyses alternative trapping tools for Aedes and Anopheles vectors in LF-endemic regions. We looked at 14 research publications that discussed W. bancrofti vector trapping methods. Pyrethrum Spray Catches (PSC), one of the seven traps studied for Anopheles LF vectors, was revealed to be the second most effective strategy after HLC, successfully catching Anopheles vectors in Nigeria, Ghana, Togo, and Burkina Faso. The PSC method has several drawbacks, such as the likelihood of overlooking exophilic mosquitoes or underestimating Anopheles populations. However, exit traps offered hope for capturing exophilic mosquitoes. Anopheles populations could also be sampled using the Anopheles Gravid Trap (AGT). In contrast, the effectiveness of the Double Net Traps (DNT) and the CDC Light Trap (CDC LT) varied. Gravid mosquito traps like the OviArt Gravid Trap (AGT) were shown to be useful tools for identifying endophilic and exophilic vectors during the exploration of novel collection techniques. The Stealth trap (ST) was suggested for sampling Anopheles mosquitoes, although specimen damage may make it difficult to identify the species. Although it needs more confirmation, the Ifakara Tent Trap C design (ITT-C) showed potential for outdoor mosquito sampling in Tanzania. Furvela tent traps successfully captured a variety of Anopheles species and are appropriate for use in a variety of eco-epidemiological settings. By contrast, for Aedes LF vectors, no specific sampling tool was identified for Aedes niveus, necessitating further research and development. However, traps like the Duplex cone trap, Resting Bucket Trap (RB), and Sticky Resting Bucket trap (SRB) proved effective for sampling Aedes albopictus, offering potential alternatives to HLC. This review emphasises the value of looking into alternative trapping methods for Aedes and Anopheles vectors in the LF-endemic region. Further research is required to determine the efficacy of novel collection techniques in various contexts, even if PSC and AGT show promise for sampling Anopheles vectors. The identified traps, along with ongoing research, provide valuable contributions to vector surveillance efforts in LF-endemic regions, enabling LF control and elimination strategies to advance.
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Affiliation(s)
- Arumugam Bhuvaneswari
- Indian Council of Medical Research—Vector Control Research Centre, Puducherry 605006, India; (A.B.); (K.H.K.R.); (A.K.)
| | | | - Kishan Hari K. Raju
- Indian Council of Medical Research—Vector Control Research Centre, Puducherry 605006, India; (A.B.); (K.H.K.R.); (A.K.)
| | - Ashwani Kumar
- Indian Council of Medical Research—Vector Control Research Centre, Puducherry 605006, India; (A.B.); (K.H.K.R.); (A.K.)
- Center for Global Health Research, Saveetha Medical College and Hospital, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai 605102, India
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Okafor MA, Ekpo ND, Opara KN, Udoidung NI, Ataya FS, Yaro CA, Batiha GES, Alexiou A, Papadakis M. Pyrethroid insecticides susceptibility profiles and evaluation of L1014F kdr mutant alleles in Culex quinquefasciatus from lymphatic filariasis endemic communities. Sci Rep 2023; 13:18716. [PMID: 37907533 PMCID: PMC10618241 DOI: 10.1038/s41598-023-44962-2] [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: 02/05/2023] [Accepted: 10/13/2023] [Indexed: 11/02/2023] Open
Abstract
This study investigated the dynamics in pyrethriod resistance and the presence/frequencies of L1014F knockdown resistance mutant allelles in Culex quinquefasciatus vector populations from Uruan Local Government Area of AkwaIbom State, Southern Nigeria between the months of March and November, 2021. Uruan LGA is among the endemic LGAs for lymphatic filariasis in AkwaIbomState. Female Anopheles mosquitoes from Eman Uruan, Ituk Mbang and Idu Uruan were exposed to permethrin, deltamethrin and alphacypermethrin in CDC insecticide coated bottles for susceptibility bioassay following standard protocols. The mosquitoes were obtained as aquatic forms from the study sites and reared under laboratory conditions to adults. The adult mosquitoes were used for this study. All the mosquitoes used for the insecticide susceptibility bioassay were morphologically identified. Standard Polymerase chain reaction (PCR) was used for authenticating the Culex quinquefasciatus species. A portion of the vgsc (917 bp) gene spanning the entire intron and the exon containing the L1014F mutation associated with knockdown resistance (kdr) in the vectorswere amplified using Allele-SPECIFIC POLYMERASE CHAIN REACTION (AS-PCR) in order to detect target site insensitivity in the vectors from the study sites. Results obtained revealed that vectors from all the study sites were resistant to permethrin insecticide (mortality rate: 18-23%). Suspected resistance (mortality rate: 90-93%) to deltamethrin and low resistance (mortality rate: 82-85%) to alphacypermethrin insecticides were detected. knockdown was more rapid with deltamethrin and alphacypermethrin than with permethrin across the study sites considering their KDT50 and KDT95. The frequency of the resistant phenotypes ranged from 35.14 to 55.3% across the study sites with a net of 45.1% resistant phenotype recorded in this study. The 1014F allelic frequency calculated from Hardy-Weinberg principle for vector populations across the study sites ranged from 0.500 (50.00%) to 0.7763 (77.63%). All populations witnessed significant (p < 0.05) deviations from Hardy-Weinberg equilibrium in the distribution of these alleles. The findings of this study show that there is a tendency to record an entire population of resistant vectors in this study area over time due to natural selection. The public health implication of these findings is that the use of pyrethroid based aerosols, coils, sprays, LLITNs and others for the purpose of controlling vectors of lymphatic filariasis and other diseases may be effort in futility.
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Affiliation(s)
- Martina Anurika Okafor
- Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom State, Nigeria
| | - Ndifreke Daniel Ekpo
- Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom State, Nigeria.
| | - Kenneth Nnamdi Opara
- Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom State, Nigeria
| | - Nsima Ibanga Udoidung
- Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom State, Nigeria
| | - Farid S Ataya
- Department of Biochemistry, College of Science, King Saud University, PO Box 2455, 11451, Riyadh, Saudi Arabia.
| | - Clement Ameh Yaro
- Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom State, Nigeria.
| | - Gaber El-Saber Batiha
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour, AlBeheira, 22511, Egypt
| | - Athanasios Alexiou
- Department of Science and Engineering, Novel Global Community Educational Foundation, Hebersham, NSW, 2770, Australia
- AFNP Med, 1030, Wien, Austria
| | - Marios Papadakis
- Department of Surgery II, University Hospital Witten-Herdecke, University of Witten-Herdecke, Heusnerstrasse 40, 42283, Wuppertal, Germany.
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Forson AO, Awuah RB, Mohammed AR, Owusu-Asenso CM, Akosah-Brempong G, Abdulai A, Sraku IK, Dhikrullahi SB, Atakora SB, Attah SK, Afrane YA. Coverage of preventive measures and surveillance for neglected tropical diseases in hard-to-reach communities in Ghana. BMC Public Health 2023; 23:1784. [PMID: 37710219 PMCID: PMC10500849 DOI: 10.1186/s12889-023-16652-1] [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: 02/19/2023] [Accepted: 08/30/2023] [Indexed: 09/16/2023] Open
Abstract
BACKGROUND Neglected tropical diseases (NTDs) are a major public health burden which mainly affects poor populations living in tropical environments and hard-to-reach areas. The study sought to examine coverage of preventive efforts, and case surveillance for NTDs in hard-to-reach communities in Ghana. METHODS The study investigated treatment efforts for lymphatic filariasis (LF), and onchocerciasis and schistosomiasis/soil transmitted helminths (SCH/STH) at household level, in difficult-to-access communities in Ghana. A total of 621 households were sampled from 6 communities in the Western, Oti and Greater Accra regions. RESULTS Over 95% of the households surveyed were covered under mass drug administration (MDA) campaigns for lymphatic filariasis (LF) and onchocerciasis. More than 80% of households had received at least two visits by community drug distributors under the MDA campaigns in the last two years preceding the study. In addition, over 90% of households in the LF and onchocerciasis endemic communities had at least one member using anthelminthic medications under the MDA campaigns in the 12 months preceding the study. However, households where no member had taken anthelminthic medications in 12 months preceding the study were over 6 times likely to have someone in the household with LF. CONCLUSIONS This study determined that SCH/STH, LF and onchocerciasis are of serious public health concern in some communities in Ghana. There is an urgent need for holistic practical disease control plan involving both financial and community support to ensure total control of NTDs in difficult-to-access communities is achieved.
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Affiliation(s)
- Akua Obeng Forson
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
- Department of Medical Laboratory Sciences, School of Biomedical and Allied Health Sciences, University of Ghana, Korle-Bu, Accra, Ghana
| | - Raphael Baffour Awuah
- Regional Institute for Population Studies (RIPS), University of Ghana, Legon. Accra, Ghana
| | - Abdul Rahim Mohammed
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Christopher Mfum Owusu-Asenso
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Gabriel Akosah-Brempong
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Anisa Abdulai
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Isaac Kwame Sraku
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Shittu B Dhikrullahi
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Sefa Bonsu Atakora
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Simon K Attah
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana
| | - Yaw Asare Afrane
- Department of Medical Microbiology, Centre for Vector-Borne Diseases Research, University of Ghana Medical School, University of Ghana, Korle-Bu, Accra, Ghana.
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Tia IZ, Barreaux AMG, Oumbouke WA, Koffi AA, Ahoua Alou LP, Camara S, Wolie RZ, Sternberg ED, Dahounto A, Yapi GY, Thomas MB, N'Guessan R. Efficacy of a 'lethal house lure' against Culex quinquefasciatus from Bouaké city, Côte d'Ivoire. Parasit Vectors 2023; 16:300. [PMID: 37641104 PMCID: PMC10463874 DOI: 10.1186/s13071-023-05883-1] [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: 04/06/2023] [Accepted: 07/14/2023] [Indexed: 08/31/2023] Open
Abstract
BACKGROUND Eave tube technology is a novel method of insecticide application that uses an electrostatic coating system to boost insecticide efficacy against resistant mosquitoes. A series of previous experiments showed encouraging insecticidal effects against malaria vectors. This study was undertaken to assess the effects of the eave tube approach on other Culicidae, in particular Culex quinquefasciatus, under laboratory and semi-field conditions. METHODS Larvae of Cx. quinquefasciatus from Bouaké were collected and reared to adult stage, and World Health Organization (WHO) cylinder tests were performed to determine their resistance status. WHO standard 3-min cone bioassays were conducted using PermaNet 2.0 netting versus eave tube-treated inserts. To assess the transient exposure effect on Cx. quinquefasciatus, eave tube assay utilizing smelly socks as attractant was performed with exposure time of 30 s, 1 min, and 2 min on 10% beta-cyfluthrin-treated inserts. Residual activity of these treated inserts was then monitored over 9 months. Field tests involving release-recapture of Cx. quinquefasciatus within enclosures around experimental huts fitted with windows and untreated or insecticide-treated eave tubes were conducted to determine house entry preference and the impact of tubes on the survival of this species. RESULTS Bouaké Cx. quinquefasciatus displayed high resistance to three out of four classes of insecticides currently used in public health. After 3 min of exposure in cone tests, 10% beta-cyfluthrin-treated inserts induced 100% mortality in Cx. quinquefasciatus, whereas the long-lasting insecticidal net (LLIN) only killed 4.5%. With reduced exposure time on the eave tube insert, mortality was still 100% after 2 min, 88% after 1 min, and 44% after 30 s. Mortality following 1 h exposure on 10% beta-cyfluthrin-treated insert was > 80% continuously up to 7 months post-treatment. Data suggest that Cx. quinquefasciatus have a stronger preference for entering a house through the eaves than through windows. Beta-cyfluthrin-treated inserts were able to kill 51% of resistant Cx. quinquefasciatus released within the enclosure. CONCLUSIONS Eave tubes are a novel method for delivery of insecticide to the house. They attract nuisance host-seeking Cx. quinquefasciatus mosquitoes and are as effective in controlling them as they are against pyrethroid-resistant Anopheles gambiae, despite the high level of resistance Cx. quinquefasciatus have developed.
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Affiliation(s)
- Innocent Z Tia
- Vector Control Products Evaluation Centre (VCPEC)/Institut Pierre Richet (IPR), Bouaké, Côte d'Ivoire.
- Institut Pierre Richet (IPR)/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire.
- Université Alassane Ouattara, Bouaké, Côte d'Ivoire.
- Centre d'Entomologie Médical et Vétérinaire (CEMV), Bouaké, Côte d'Ivoire.
| | - Antoine M G Barreaux
- Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), 34398, Montpellier, France
| | - Welbeck A Oumbouke
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L35 QA, UK
| | - Alphonsine A Koffi
- Vector Control Products Evaluation Centre (VCPEC)/Institut Pierre Richet (IPR), Bouaké, Côte d'Ivoire
- Institut Pierre Richet (IPR)/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
| | - Ludovic P Ahoua Alou
- Vector Control Products Evaluation Centre (VCPEC)/Institut Pierre Richet (IPR), Bouaké, Côte d'Ivoire
- Institut Pierre Richet (IPR)/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
| | - Soromane Camara
- Vector Control Products Evaluation Centre (VCPEC)/Institut Pierre Richet (IPR), Bouaké, Côte d'Ivoire
- Institut Pierre Richet (IPR)/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
| | - Rosine Z Wolie
- Vector Control Products Evaluation Centre (VCPEC)/Institut Pierre Richet (IPR), Bouaké, Côte d'Ivoire
- Institut Pierre Richet (IPR)/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
- Unité de Recherche et de Pédagogie de Génétique, UFR Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire
| | - Eleanore D Sternberg
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L35 QA, UK
| | - Amal Dahounto
- Laboratoire de Bio-Mathématique et d'Estimation Forestière, Université d'Abomey Calavi, Cotonou, Bénin
| | - Gregoire Y Yapi
- Université Alassane Ouattara, Bouaké, Côte d'Ivoire
- Centre d'Entomologie Médical et Vétérinaire (CEMV), Bouaké, Côte d'Ivoire
| | | | - Raphael N'Guessan
- Vector Control Products Evaluation Centre (VCPEC)/Institut Pierre Richet (IPR), Bouaké, Côte d'Ivoire. raphael.n'
- Institut Pierre Richet (IPR)/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire. raphael.n'
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK. raphael.n'
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10
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Shaw C, McLure A, Graves PM, Lau CL, Glass K. Lymphatic filariasis endgame strategies: Using GEOFIL to model mass drug administration and targeted surveillance and treatment strategies in American Samoa. PLoS Negl Trop Dis 2023; 17:e0011347. [PMID: 37200375 DOI: 10.1371/journal.pntd.0011347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 05/31/2023] [Accepted: 04/29/2023] [Indexed: 05/20/2023] Open
Abstract
American Samoa underwent seven rounds of mass drug administration (MDA) for lymphatic filariasis (LF) from 2000-2006, but subsequent surveys found evidence of ongoing transmission. American Samoa has since undergone further rounds of MDA in 2018, 2019, and 2021; however, recent surveys indicate that transmission is still ongoing. GEOFIL, a spatially-explicit agent-based LF model, was used to compare the effectiveness of territory-wide triple-drug MDA (3D-MDA) with targeted surveillance and treatment strategies. Both approaches relied on treatment with ivermectin, diethylcarbamazine, and albendazole. We simulated three levels of whole population coverage for 3D-MDA: 65%, 73%, and 85%, while the targeted strategies relied on surveillance in schools, workplaces, and households, followed by targeted treatment. In the household-based strategies, we simulated 1-5 teams travelling village-to-village and offering antigen (Ag) testing to randomly selected households in each village. If an Ag-positive person was identified, treatment was offered to members of all households within 100m-1km of the positive case. All simulated interventions were finished by 2027 and their effectiveness was judged by their 'control probability'-the proportion of simulations in which microfilariae prevalence decreased between 2030 and 2035. Without future intervention, we predict Ag prevalence will rebound. With 3D-MDA, a 90% control probability required an estimated ≥ 4 further rounds with 65% coverage, ≥ 3 rounds with 73% coverage, or ≥ 2 rounds with 85% coverage. While household-based strategies were substantially more testing-intensive than 3D-MDA, they could offer comparable control probabilities with substantially fewer treatments; e.g. three teams aiming to test 50% of households and offering treatment to a 500m radius had approximately the same control probability as three rounds of 73% 3D-MDA, but used < 40% the number of treatments. School- and workplace-based interventions proved ineffective. Regardless of strategy, reducing Ag prevalence below the 1% target threshold recommended by the World Health Organization was a poor indicator of the interruption of LF transmission, highlighting the need to review blanket elimination targets.
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Affiliation(s)
- Callum Shaw
- National Centre for Epidemiology and Population Health, Australian National University, Canberra, ACT, Australia
| | - Angus McLure
- National Centre for Epidemiology and Population Health, Australian National University, Canberra, ACT, Australia
| | - Patricia M Graves
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Cairns, Queensland, Australia
| | - Colleen L Lau
- School of Public Health, Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia
| | - Kathryn Glass
- National Centre for Epidemiology and Population Health, Australian National University, Canberra, ACT, Australia
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11
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Nasiri Z, Hosseinizadeh ZS, Sayyadi Z, Alipour H. Entomological survey of malaria vectors in Dashtestan County, South of Iran. J Parasit Dis 2023; 47:161-166. [PMID: 36910314 PMCID: PMC9998789 DOI: 10.1007/s12639-022-01555-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 11/21/2022] [Indexed: 12/03/2022] Open
Abstract
Anopheline mosquitoes are responsible for transmission of some diseases such as malaria. This study was carried out in five villages of Dashtestan county, Bushehr province, south of Iran with mountainous and plain areas. Anopheles larvae were sampled once a month from May to July 2021 by dipping method using standard dippers. Adults were captured by the total catch technique. In this study, 1062 Anopheles mosquitoes were collected including 850 adults and 212 larvae. Samples were A. superpictus, A. stephensi, A. dthali and A. fluviatilis. The dominant species at all sites (larvae and adults) were A. dthali (31.35%), A. superpictus (28.93%), A. stephensi (27.77%), and A. fluviatilis (11.95%), respectively. Among adults, A. stephensi was the most frequent species, but among larvae, A. dthali was the dominant species. The highest number of A. dthali was captured from Dalaki village with 35%, while A. superpictus and A. fluviatilis were not caught at this station. The minimum collected adults of all species occurred in Bashirabad. This result showed that A. stephensi plays an important role in south Iran, which is under the elimination phase. The fauna and niches of Anopheles has different patterns depending on ecological, climatic, and topographic features. These items affect host preferences, feeding behaviors, and distribution of these species. A monthly or annual entomological survey is necessary in regions with mobile populations since imported malaria is a problematic issue in the elimination programs of Iran.
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Affiliation(s)
- Zahra Nasiri
- Student Research Committee and Department of Biology and Control of Disease Vectors, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Zahra-Sadat Hosseinizadeh
- Student Research Committee and Department of Biology and Control of Disease Vectors, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Zeinab Sayyadi
- Student Research Committee and Department of Biology and Control of Disease Vectors, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hamzeh Alipour
- Research Center for Health Sciences, Institute of Health, Shiraz University of Medical Sciences, Shiraz, Iran
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12
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Sharma S, Smith ME, Bilal S, Michael E. Evaluating elimination thresholds and stopping criteria for interventions against the vector-borne macroparasitic disease, lymphatic filariasis, using mathematical modelling. Commun Biol 2023; 6:225. [PMID: 36849730 PMCID: PMC9971242 DOI: 10.1038/s42003-022-04391-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Accepted: 12/20/2022] [Indexed: 03/01/2023] Open
Abstract
We leveraged the ability of EPIFIL transmission models fit to field data to evaluate the use of the WHO Transmission Assessment Survey (TAS) for supporting Lymphatic Filariasis (LF) intervention stopping decisions. Our results indicate that understanding the underlying parasite extinction dynamics, particularly the protracted transient dynamics involved in shifts to the extinct state, is crucial for understanding the impacts of using TAS for determining the achievement of LF elimination. These findings warn that employing stopping criteria set for operational purposes, as employed in the TAS strategy, without a full consideration of the dynamics of extinction could seriously undermine the goal of achieving global LF elimination.
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Affiliation(s)
- Swarnali Sharma
- Christian Medical College, IDA Scudder Road, Vellore, Tamil Nadu, 632004, India.
| | - Morgan E Smith
- Department of Biological Sciences, University of Notre Dame, Notre Dame, South Bend, IN, USA
| | - Shakir Bilal
- Center for Global Health Infectious Disease Research, University of South Florida, Tampa, FL, USA
| | - Edwin Michael
- Center for Global Health Infectious Disease Research, University of South Florida, Tampa, FL, USA.
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13
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Simpson H, Mengiste A, Mbonigaba JB, Kollie K, Nganda M, Dean L, Argaw D, Davey G, Semrau M. Research priorities to support the development of integrated national strategies to control skin-neglected tropical diseases. Trans R Soc Trop Med Hyg 2023; 117:132-138. [PMID: 36130404 PMCID: PMC9890312 DOI: 10.1093/trstmh/trac086] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 08/04/2022] [Accepted: 08/25/2022] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Skin-presenting neglected tropical diseases (skin-NTDs) impose large burdens on affected people, families and communities. The NTD Roadmap 2021-2030 presents a strategic plan to guide collaborative, multisectoral action to overcome these burdens, defining targets to control, eliminate and/or eradicate skin-NTDs by 2030. One of its targets is for 40 countries to adopt integrated skin-NTD strategies. Despite this high-level support for integration, only four countries were implementing integrated skin-NTD strategies in 2020. METHODS We hosted workshops at the 2021 annual meeting of the Coalition for Operational Research on NTDs, to discuss the operationalisation of Roadmap goals into national strategies and interventions for skin-NTD control. Speakers included NTD Programme Managers from NTD-endemic countries, technical experts and researchers of different aspects of skin-NTDs. RESULTS Challenges include community perceptions of interventions, demonstrating the cost-effectiveness of integrated care, availability and accessibility of community-based and primary healthcare services, the quality of data on skin-NTD morbidity and changes to operational structures required for integration. Research priorities included the identification of optimal case detection platforms, evaluation of integrated care, understanding the impacts of integration on community members and community health staff and development of point-of-care diagnostics. CONCLUSIONS The operational research priorities are intended to support the scale-up of integrated skin-NTDs programmes.
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Affiliation(s)
- Hope Simpson
- Centre for Global Health Research, Brighton and Sussex Medical School, Brighton BN1 9PX, UK.,Department of Disease Control, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Asrat Mengiste
- College of Health Sciences, Addis Ababa University, 2Q92+P2W, Addis Ababa, Ethiopia
| | - Jean Bosco Mbonigaba
- Rwanda Neglected Tropical Diseases Programme, Rwanda Biomedical Centre, Ministry of Health 23VV+3MM, Kigali, Rwanda
| | - Karsor Kollie
- Non Communicable and Neglected Tropical Disease Program in the Ministry of Health and Social Welfare, 8643+F7C, Monrovia, Liberia
| | - Motto Nganda
- Capacity Research Unit, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Laura Dean
- Capacity Research Unit, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Daniel Argaw
- Department of Control of Neglected Tropical Diseases, World Health Organization, 1211 Geneva, Switzerland
| | - Gail Davey
- Centre for Global Health Research, Brighton and Sussex Medical School, Brighton BN1 9PX, UK
| | - Maya Semrau
- Centre for Global Health Research, Brighton and Sussex Medical School, Brighton BN1 9PX, UK
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14
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Msoffe R, Hewitt M, Masalu JP, Finda M, Kavishe DR, Okumu FO, Mpolya EA, Kaindoa EW, Killeen GF. Participatory development of practical, affordable, insecticide-treated mosquito proofing for a range of housing designs in rural southern Tanzania. Malar J 2022; 21:318. [PMCID: PMC9636681 DOI: 10.1186/s12936-022-04333-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Accepted: 10/18/2022] [Indexed: 11/08/2022] Open
Abstract
Abstract
Background
Insecticidal mosquito-proof netting screens could combine the best features of insecticide-treated nets (ITNs) and indoor residual spraying (IRS), the two most important front line vector control interventions in Africa today, and also overcome the most important limitations of these methods. This study engaged members of a rural Tanzanian community in developing and evaluating simple, affordable and scalable procedures for installing readily available screening materials on eave gaps and windows of their own houses, and then treating those screens with a widely used IRS formulation of the organophosphate insecticide pirimiphos-methyl (PM).
Methods
A cohort of 54 households recruited upon consent, following which the structural features and occupant demographics of their houses were surveyed. Indoor mosquito densities were surveyed longitudinally, for approximately 3 months before and over 5 months after participatory house modification and screening using locally available materials. Each house was randomly assigned to one of three study arms: (1) No screens installed until the end of the study (negative control), (2) untreated screens installed, and (3) screened installed and then treated with PM, the insecticidal activity of which was subsequently assessed using standard cone assays.
Results
Almost all (52) recruited households participated until the end, at which point all houses had been successfully screened. In most cases, screening was only installed after making enabling structural modifications that were accepted by the enrolled households. Compared to unscreened houses, houses with either treated or untreated screens both almost entirely excluded Anopheles arabiensis (Relative reduction (RR) ≥ 98%, P < < 0.0001), the most abundant local malaria vector. However, screens were far less effective against Culex quinquefasciatus (RR ≤ 46%, P < < 0.0001), a non-malaria vector causing considerable biting nuisance, regardless of their treatment status. While PM did not augment household level protection by screens against either mosquito species (P = 0.676 and 0.831, respectively), 8 months after treatment it still caused 73% and 89% mortality among susceptible insectary-reared Anopheles gambiae following exposures of 3 and 30 min, respectively.
Conclusions
Participatory approaches to mosquito proofing houses may be acceptable and effective, and installed screens may be suitable targets for residual insecticide treatments.
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15
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Wheeler NJ, Hallem EA, Zamanian M. Making sense of sensory behaviors in vector-borne helminths. Trends Parasitol 2022; 38:841-853. [PMID: 35931639 PMCID: PMC9481669 DOI: 10.1016/j.pt.2022.07.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/07/2022] [Accepted: 07/10/2022] [Indexed: 10/16/2022]
Abstract
Migrations performed by helminths are impressive and diverse, and accumulating evidence shows that many are controlled by sophisticated sensory programs. The migrations of vector-borne helminths are particularly complex, requiring precise, stage-specific regulation. We review the contrasting states of knowledge on snail-borne schistosomes and mosquito-borne filarial nematodes. Rich observational data exist for the chemosensory behaviors of schistosomes, while the molecular sensory pathways in nematodes are well described. Recent investigations on the molecular mechanisms of sensation in schistosomes and filarial nematodes have revealed some features conserved within their respective phyla, but adaptations correlated with parasitism are pronounced. Technological developments are likely to extend these advances, and we forecast how these technologies may be applied.
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Affiliation(s)
- Nicolas J Wheeler
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Elissa A Hallem
- Department of Microbiology, Immunology & Molecular Genetics and Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Mostafa Zamanian
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, USA.
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16
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Risk Factors of Noncompliance to Preventive Mass Drug Administration for Eliminating Lymphatic Filariasis: A Case-Control Study in Jawi District, Northwest Ethiopia. J Trop Med 2022; 2022:4792280. [PMID: 36187459 PMCID: PMC9519346 DOI: 10.1155/2022/4792280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/06/2022] [Indexed: 11/17/2022] Open
Abstract
Background. High compliance is crucial for the success of a mass drug administration program to achieve lymphatic filariasis elimination. However, the presence of persistently noncompliant individuals might delay the elimination target. Besides, although context-based research is essential to designing effective strategies, only a few studies have focused on identifying factors that play a role in noncompliance with mass drug administration in Africa. Therefore, this study was conducted to identify the factors associated with noncompliance to prevent mass drug administration using ivermectin-with-albendazole for the elimination of lymphatic filariasis in Northwest Ethiopia. Methods. A case-control study was conducted in Jawi District, Northwest Ethiopia. All individuals who are permanently living in the study area and registered on the annual chemotherapy registration book since 2015 were included in this study. A two-proportion formula was used to estimate the required sample size and 348 cases and 348 controls were selected by identification number on the village chemotherapy registration book using a systematic sampling technique. Data were collected by face-to-face interviews using a structured questionnaire developed through an intensive literature review. Then, data were entered and cleaned by using the EPI DATA software, and analyses were conducted using SPSS version 26. Finally, a logistic regression analysis technique was applied to identify the risk factors using adjusted odds ratio as measures of effect. Results. A total of 690 (99.1%) participants, 345 cases and 345 controls, were included in the study. Younger age (AOR = 1.60; 95%CI: 1.10, 2.33), female sex (AOR = 1.56; 95%CI: 1.24, 3.93), thought of not being susceptible to the disease (AOR = 2.36, 95%CI: 1.80, 4.32), lack of disease knowledge (AOR = 1.88; 95% CI: 1.38, 3.81), fear of drug side effect (AOR = 2.45; 95% CI:1.23, 4.86), and not participating in community drug distributors selection (AOR = 2.58; 95% CI: 1.70, 3.91) were found to be the risk factors significantly associated with noncompliance. Conclusion. Noncompliance with lymphatic filariasis mass drug administration therapy was associated with specific demographic, individual, program, and drug delivery characteristics. This finding has important implications for program effectiveness and would be used to accelerate the elimination of lymphatic filariasis in the study area and other endemic settings.
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17
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Coulibaly YI, Sangare M, Dolo H, Soumaoro L, Coulibaly SY, Dicko I, Diabaté AF, Diarra L, Coulibaly ME, Doumbia SS, Diallo AA, Dembele M, Koudou BG, Bockarie MJ, Kelly-Hope LA, Klion AD, Nutman TB. No evidence of lymphatic filariasis transmission in Bamako urban setting after three mass drug administration rounds. Parasitol Res 2022; 121:3243-3248. [PMID: 36066741 PMCID: PMC9556341 DOI: 10.1007/s00436-022-07648-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 08/30/2022] [Indexed: 11/25/2022]
Abstract
Lymphatic filariasis (LF) elimination activities started in Mali in 2005 in the most endemic areas and reached countrywide coverage in 2009. In 2004, the district of Bamako was endemic for LF with a prevalence of 1.5%. The current study was designed to determine LF endemicity level in the urban area of Bamako after three rounds of ivermectin and albendazole mass drug administration (MDA). A cross-sectional study was conducted in 2011 in Bamako city, consisting of human prevalence and entomological surveys. Volunteers aged 14 years and above were invited to participate and tested for evidence of Wuchereria bancrofti using night time blood thick smear microfilarial count and blood spots for LF antibodies using the SD BIOLINE Oncho/LF IgG4 Biplex rapid test (Ov16/Wb123). Mosquitoes were collected using CDC light and gravid traps and tested using molecular methods. Poolscreen software v2.0 was used to estimate vector transmission potential. Of the 899 volunteers, one (0.11%) was found to be positive for LF using the Oncho/LF IgG4 Biplex rapid test, and none was found to have Wuchereria bancrofti microfilariae. No mosquitoes were found infected among 6174 Culex spp. (85.2%), 16 Anopheles gambiae s.l. (An. gambiae s.l.) (0.2%), 26 Aedes spp. (0.4%), 858 Ceratopogonidae (11.8%) and 170 other insects not identified (2.3%) tested. Our data indicate that there was no active LF transmission in the low prevalence urban district of Bamako after three MDA rounds. These data helped the National LF programme move forward towards the elimination goal.
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Affiliation(s)
- Yaya Ibrahim Coulibaly
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali.,Dermatology Hospital of Bamako, Bamako, Mali
| | - Moussa Sangare
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali. .,Interdisciplinary School of Health Sciences
- Faculty of Health Sciences, University of Ottawa, Ottawa, ON, K1N 6N5, Canada.
| | - Housseini Dolo
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Lamine Soumaoro
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Siaka Yamoussa Coulibaly
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Ilo Dicko
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Abdoul Fatao Diabaté
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Lamine Diarra
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Michel Emmanuel Coulibaly
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Salif Seriba Doumbia
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Abdallah Amadou Diallo
- Mali - International Center of Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | - Massitan Dembele
- National Lymphatic Filariasis Elimination Program, Ministry of Health and Public Hygiene, Bamako, Mali
| | - Benjamin G Koudou
- Centre Suisse de Recherche Scientifiques en Côte d'Ivoire, 01 BP 1303 Abidjan 01, Abidjan, Côte d'Ivoire.,UFR Science de la Nature, Université Nangui Abrogoua, 02 BP 801 Abidjan 01, Abidjan, Côte d'Ivoire
| | | | - Louise A Kelly-Hope
- Centre for Neglected Tropical Diseases, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, UK.,Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Amy D Klion
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Thomas B Nutman
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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18
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Laman M, Tavul L, Karl S, Kotty B, Kerry Z, Kumai S, Samuel A, Lorry L, Timinao L, Howard SC, Makita L, John L, Bieb S, Wangi J, Albert JM, Payne M, Weil GJ, Tisch DJ, Bjerum CM, Robinson LJ, King CL. Mass drug administration of ivermectin, diethylcarbamazine, plus albendazole compared with diethylcarbamazine plus albendazole for reduction of lymphatic filariasis endemicity in Papua New Guinea: a cluster-randomised trial. THE LANCET INFECTIOUS DISEASES 2022; 22:1200-1209. [PMID: 35533701 PMCID: PMC9300473 DOI: 10.1016/s1473-3099(22)00026-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 11/28/2021] [Accepted: 01/10/2022] [Indexed: 11/15/2022]
Abstract
Background Methods Findings Interpretation Funding
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Affiliation(s)
- Moses Laman
- Papua New Guinea Institute for Medical Research, Goroka, Papua New Guinea
| | - Livingstone Tavul
- Papua New Guinea Institute for Medical Research, Goroka, Papua New Guinea
| | - Stephan Karl
- Papua New Guinea Institute for Medical Research, Goroka, Papua New Guinea; Australian Institute of Tropical Health and Medicine, James Cook University, Smithfield, QLD, Australia
| | - Bethuel Kotty
- Papua New Guinea Institute for Medical Research, Goroka, Papua New Guinea
| | - Zebede Kerry
- Papua New Guinea Institute for Medical Research, Goroka, Papua New Guinea
| | - Stephen Kumai
- Papua New Guinea Institute for Medical Research, Goroka, Papua New Guinea
| | - Anna Samuel
- Papua New Guinea Institute for Medical Research, Goroka, Papua New Guinea
| | - Lina Lorry
- Papua New Guinea Institute for Medical Research, Goroka, Papua New Guinea
| | - Lincoln Timinao
- Papua New Guinea Institute for Medical Research, Goroka, Papua New Guinea
| | - S Cade Howard
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA
| | - Leo Makita
- National Department of Health, Waigani, Papua New Guinea
| | - Lucy John
- National Department of Health, Waigani, Papua New Guinea
| | - Sibauk Bieb
- National Department of Health, Waigani, Papua New Guinea
| | - James Wangi
- WHO Papua New Guinea, NTD Program, Waigani, Papua New Guinea
| | - Jeffrey M Albert
- Department of Population and Quantitative Health Sciences, Case Western Reserve University, Cleveland, OH, USA
| | - Michael Payne
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA
| | - Gary J Weil
- Department of Medicine, Washington University, St Louis, MO, USA
| | - Daniel J Tisch
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA; Department of Population and Quantitative Health Sciences, Case Western Reserve University, Cleveland, OH, USA
| | - Catherine M Bjerum
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA
| | - Leanne J Robinson
- Papua New Guinea Institute for Medical Research, Goroka, Papua New Guinea; Burnet Institute, Melbourne, VIC, Australia; Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, Australia
| | - Christopher L King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA; Veterans Affairs Research Administration, Cleveland, OH, USA.
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19
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Martín G, Erinjery JJ, Ediriweera D, de Silva HJ, Lalloo DG, Iwamura T, Murray KA. A mechanistic model of snakebite as a zoonosis: Envenoming incidence is driven by snake ecology, socioeconomics and its impacts on snakes. PLoS Negl Trop Dis 2022; 16:e0009867. [PMID: 35551272 PMCID: PMC9129040 DOI: 10.1371/journal.pntd.0009867] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 05/24/2022] [Accepted: 04/07/2022] [Indexed: 12/05/2022] Open
Abstract
Snakebite is the only WHO-listed, not infectious neglected tropical disease (NTD), although its eco-epidemiology is similar to that of zoonotic infections: envenoming occurs after a vertebrate host contacts a human. Accordingly, snakebite risk represents the interaction between snake and human factors, but their quantification has been limited by data availability. Models of infectious disease transmission are instrumental for the mitigation of NTDs and zoonoses. Here, we represented snake-human interactions with disease transmission models to approximate geospatial estimates of snakebite incidence in Sri Lanka, a global hotspot. Snakebites and envenomings are described by the product of snake and human abundance, mirroring directly transmitted zoonoses. We found that human-snake contact rates vary according to land cover (surrogate of occupation and socioeconomic status), the impacts of humans and climate on snake abundance, and by snake species. Our findings show that modelling snakebite as zoonosis provides a mechanistic eco-epidemiological basis to understand snakebites, and the possible implications of global environmental and demographic change for the burden of snakebite.
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Affiliation(s)
- Gerardo Martín
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, United Kingdom
- Departamento de Sistemas y Procesos Naturales, Escuela Nacional de Estudios Superiores unidad Mérida, Universidad Nacional Autónoma de México, Mérida, México
- * E-mail:
| | - Joseph J. Erinjery
- School of Zoology, Department of Life Sciences, Tel Aviv University, Tel Aviv, Israel
- Department of Zoology, Kannur University, Kannur, India
| | | | | | - David G. Lalloo
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Takuya Iwamura
- Department of Forest Ecosystems and Society, College of Forestry, Oregon State University, Corvallis, Oregon, United States of America
| | - Kris A. Murray
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, United Kingdom
- MRC Unit The Gambia at London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia
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20
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Swart Z, Duong TA, Wingfield BD, Postma A, Slippers B. The relevance of studying insect-nematode interactions for human disease. Pathog Glob Health 2022; 116:140-145. [PMID: 34726122 PMCID: PMC9090338 DOI: 10.1080/20477724.2021.1996796] [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] [Indexed: 10/19/2022] Open
Abstract
Vertebrate-parasitic nematodes cause debilitating, chronic infections in millions of people worldwide. The burden of these so-called 'neglected tropical diseases' is often carried by poorer socioeconomic communities in part because research on parasitic nematodes and their vertebrate hosts is challenging and costly. However, complex biological and pathological processes can be modeled in simpler organisms. Here, we consider how insight into the interactions between entomopathogenic nematodes (EPN), their insect hosts and bacterial symbionts may reveal novel treatment targets for parasitic nematode infections. We argue that a combination of approaches that target nematodes, as well as the interaction of pathogens with insect vectors and bacterial symbionts, offer potentially effective, but underexplored opportunities.
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Affiliation(s)
- Zorada Swart
- Department of Biochemistry Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, South Africa
| | - Tuan A. Duong
- Department of Biochemistry Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, South Africa
| | - Brenda D. Wingfield
- Department of Biochemistry Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, South Africa
| | - Alisa Postma
- Department of Biochemistry Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, South Africa
| | - Bernard Slippers
- Department of Biochemistry Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, South Africa
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21
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Turner HC, Stolk WA, Solomon AW, King JD, Montresor A, Molyneux DH, Toor J. Are current preventive chemotherapy strategies for controlling and eliminating neglected tropical diseases cost-effective? BMJ Glob Health 2021; 6:bmjgh-2021-005456. [PMID: 34385158 PMCID: PMC8362715 DOI: 10.1136/bmjgh-2021-005456] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 04/23/2021] [Accepted: 04/26/2021] [Indexed: 02/07/2023] Open
Abstract
Neglected tropical diseases (NTDs) remain a significant cause of morbidity and mortality in many low-income and middle-income countries. Several NTDs, namely lymphatic filariasis, onchocerciasis, schistosomiasis, soil-transmitted helminthiases (STH) and trachoma, are predominantly controlled by preventive chemotherapy (or mass drug administration), following recommendations set by the WHO. Over one billion people are now treated for NTDs with this strategy per year. However, further investment and increased domestic healthcare spending are urgently needed to continue these programmes. Consequently, it is vital that the cost-effectiveness of preventive chemotherapy is understood. We analyse the current estimates on the cost per disability-adjusted life year (DALY) of the preventive chemotherapy strategies predominantly used for these diseases and identify key evidence gaps that require further research. Overall, the reported estimates show that preventive chemotherapy is generally cost-effective, supporting WHO recommendations. More specifically, the cost per DALY averted estimates relating to community-wide preventive chemotherapy for lymphatic filariasis and onchocerciasis were particularly favourable when compared with other public health interventions. Cost per DALY averted estimates of school-based preventive chemotherapy for schistosomiasis and STH were also generally favourable but more variable. Notably, the broader socioeconomic benefits are likely not being fully captured by the DALYs averted metric. No estimates of cost per DALY averted relating to community-wide mass antibiotic treatment for trachoma were found, highlighting the need for further research. These findings are important for informing global health policy and support the need for continuing NTD control and elimination efforts.
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Affiliation(s)
- Hugo C Turner
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, UK .,Oxford University Clinical Research Unit, Wellcome Africa Asia Programme, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Wilma A Stolk
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Anthony W Solomon
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Jonathan D King
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Antonio Montresor
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - David H Molyneux
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Jaspreet Toor
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, UK,Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
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22
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Davis EL, Prada J, Reimer LJ, Hollingsworth TD. Modelling the Impact of Vector Control on Lymphatic Filariasis Programs: Current Approaches and Limitations. Clin Infect Dis 2021; 72:S152-S157. [PMID: 33905475 PMCID: PMC8201547 DOI: 10.1093/cid/ciab191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Vector control is widely considered an important tool for lymphatic filariasis (LF) elimination but is not usually included in program budgets and has often been secondary to other policy questions in modelling studies. Evidence from the field demonstrates that vector control can have a large impact on program outcomes and even halt transmission entirely, but implementation is expensive. Models of LF have the potential to inform where and when resources should be focused, but often simplify vector dynamics and focus on capturing human prevalence trends, making them comparatively ill-designed for direct analysis of vector control measures. We review the recent modelling literature and present additional results using a well-established model, highlighting areas of agreement between model predictions and field evidence, and discussing the possible determinants of existing disagreements. We conclude that there are likely to be long-term benefits of vector control, both on accelerating programs and preventing resurgence.
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Affiliation(s)
- E L Davis
- Big Data Institute, University of Oxford, Oxford, UK
| | - J Prada
- University of Surrey, Guildford,UK
| | - L J Reimer
- Liverpool School of Tropical Medicine, Liverpool,UK
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23
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Salonga PKN, Mendoza VMP, Mendoza RG, Belizario VY. A mathematical model of the dynamics of lymphatic filariasis in Caraga Region, the Philippines. ROYAL SOCIETY OPEN SCIENCE 2021; 8:201965. [PMID: 34234950 PMCID: PMC8242838 DOI: 10.1098/rsos.201965] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 06/07/2021] [Indexed: 06/13/2023]
Abstract
Despite being one of the first countries to implement mass drug administration (MDA) for elimination of lymphatic filariasis (LF) in 2001 after a pilot study in 2000, the Philippines is yet to eliminate the disease as a public health problem with 6 out of the 46 endemic provinces still implementing MDA for LF as of 2018. In this work, we propose a mathematical model of the transmission dynamics of LF in the Philippines and a control strategy for its elimination using MDA. Sensitivity analysis using the Latin hypercube sampling and partial rank correlation coefficient methods suggests that the infected human population is most sensitive to the treatment parameters. Using the available LF data in Caraga Region from the Philippine Department of Health, we estimate the treatment rates r 1 and r 2 using the least-squares parameter estimation technique. Parameter bootstrapping showed small variability in the parameter estimates. Finally, we apply optimal control theory with the objective of minimizing the infected human population and the corresponding implementation cost of MDA, using the treatment coverage γ as the control parameter. Simulation results highlight the importance of maintaining a high MDA coverage per year to effectively minimize the infected population by the year 2030.
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Affiliation(s)
- Pamela Kim N. Salonga
- Institute of Mathematics, University of the Philippines Diliman, Quezon City, Philippines
- Natural Sciences Research Institute, University of the Philippines Diliman, Quezon City, Philippines
| | - Victoria May P. Mendoza
- Institute of Mathematics, University of the Philippines Diliman, Quezon City, Philippines
- Natural Sciences Research Institute, University of the Philippines Diliman, Quezon City, Philippines
| | - Renier G. Mendoza
- Institute of Mathematics, University of the Philippines Diliman, Quezon City, Philippines
- Natural Sciences Research Institute, University of the Philippines Diliman, Quezon City, Philippines
| | - Vicente Y. Belizario
- College of Public Health and Neglected Tropical Diseases Study Group, National Institutes of Health, University of the Philippines Manila, Philippines
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24
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Yajima A, Ichimori K. Progress in the elimination of lymphatic filariasis in the Western Pacific Region: successes and challenges. Int Health 2021; 13:S10-S16. [PMID: 33349886 PMCID: PMC7753160 DOI: 10.1093/inthealth/ihaa087] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 09/07/2020] [Accepted: 12/01/2020] [Indexed: 12/15/2022] Open
Abstract
The Western Pacific Region is the largest and most diverse region in the world, made up of 37 countries and territories in the Pacific, Oceania and parts of Asia, with a population of more than 1.9 billion people stretching over an area from China and Mongolia in the north to New Zealand in the south. In 1999, 22 countries and territories in the Pacific joined together and launched the Pacific Programme to Eliminate Lymphatic Filariasis. Shortly after, the Global Programme to Eliminate Lymphatic Filariasis was launched in 2000. In 2004, 12 countries in the Asia subregion of the Western Pacific Region and Southeast Asian Region joined and developed the Mekong-Plus Strategic Plan for Elimination of Lymphatic Filariasis. Since then, significant efforts have been made by all endemic countries, with annual mass drug administration (MDA) as a principal strategy, through strong partnership with the WHO and other donors and partners. As a result, by the end of 2019, 10 of 22 endemic countries in the region, including 8 of 16 countries in the Pacific and 2 countries in the Asia subregion, achieved WHO validation for elimination of lymphatic filariasis (LF) as a public health problem. All the other countries are either progressing with post-MDA surveillance or accelerating efforts by adoption of the new triple drug therapy strategy and enhancement of MDA campaigns to tackle persistent transmission. Some 85% of the originally endemic implementation units have stopped MDA and the number of people requiring MDA for LF in the Western Pacific Region was reduced by 72% from 2000 to 2018. This paper reviews the progress, key success factors and remaining challenges and indicates the way forward to achieve LF elimination in the Western Pacific Region.
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Affiliation(s)
- Aya Yajima
- Division of Programmes of Disease Control, World Health Organization Western Pacific Regional Office, Manila, Philippines
| | - Kazuyo Ichimori
- Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
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25
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Kima A, Guiguemde K, Serme M, Meda Z, Bougma R, Djiatsa J, Bougouma C, Drabo F. [Lymphatic Filariasis Transmission Assessment Survey in Burkina Faso in Connection with 4 Districts]. MEDECINE TROPICALE ET SANTE INTERNATIONALE 2021; 1:mtsibulletin.n1.2021.83. [PMID: 35586585 PMCID: PMC9022747 DOI: 10.48327/mtsibulletin.n1.2021.83] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 03/17/2021] [Indexed: 11/24/2022]
Abstract
Objective In this impact survey on the preventive chemotherapy against lymphatic filariasis, the national neglected tropical diseases programme team conducted a Transmission Assessment Survey in the health districts of Leo, Sapouy, Boromo and Dedougou. The purpose of this study was to assess lymphatic filariasis transmission in these four districts (included in two evaluation units (EU): Boucle du Mouhoun 3 and Centre-Ouest 2 after more than ten to thirteen years of mass drug treatment. Methodology The study was a cross sectional survey which targeted the school aged children based on the cluster survey method conducted at community level. Results Among the 1649 school aged children covered by the survey in the Centre Ouest EU, four were found positive at the Filariasis Test Strip (FTS), i.e. the proportion of children with circulating filarial antigens (i.e. with live adult stages of W. bancrofti ) was 0.24%. In the BMH3 EU, none of the 1716 children tested was FTS-positive. Conclusion From the findings, we can infer that filariasis transmission has been interrupted in these districts and that mass treatment with albendazole and ivermectin can be stopped.
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Affiliation(s)
- A. Kima
- Programme national de lutte contre les maladies tropicales négligées, Ouagadougou, Burkina Faso,*
| | - K.T. Guiguemde
- Laboratoire de parasitologie UFR-SDS, Université Ouaga 1 Joseph KI-ZERBO, Ouagadougou, Burkina Faso
| | - M. Serme
- Programme national de lutte contre les maladies tropicales négligées, Ouagadougou, Burkina Faso
| | - Z.C. Meda
- Institut supérieur des sciences de la santé, Université NAZI BONI, Bobo Dioulasso, Burkina Faso
| | - R. Bougma
- Programme national de lutte contre les maladies tropicales négligées, Ouagadougou, Burkina Faso
| | - J.P. Djiatsa
- ONG Helen Keller International, Ouagadougou, Burkina Faso
| | - C. Bougouma
- Programme national de lutte contre les maladies tropicales négligées, Ouagadougou, Burkina Faso
| | - F. Drabo
- Programme national de lutte contre les maladies tropicales négligées, Ouagadougou, Burkina Faso
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26
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Dorkenoo MA, Tchankoni MK, Yehadji D, Yakpa K, Tchalim M, Sossou E, Bronzan R, Ekouevi DK. Monitoring migrant groups as a post-validation surveillance approach to contain the potential reemergence of lymphatic filariasis in Togo. Parasit Vectors 2021; 14:134. [PMID: 33653393 PMCID: PMC7923304 DOI: 10.1186/s13071-021-04644-2] [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: 09/16/2020] [Accepted: 02/16/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In March 2017, Togo was declared the first country in sub-Saharan Africa to eliminate lymphatic filariasis as a public health problem, but post-validation surveillance has been lacking. In some areas of the country, migrant groups from neighboring countries that are still endemic for LF pose a risk of reintroduction of LF to Togo. The objective of this study was to identify the risk posed by migrant groups by measuring their prevalence of LF infection and investigating any positive case using Togo's case investigation algorithm to prevent resurgence of LF and sustain Togo's elimination success. METHOD A cross-sectional study was conducted in 2018 in the northernmost region of the country. Three migrant populations were identified: (i) nomadic Peuhls, (ii) Togolese members of local communities who migrate annually to neighboring countries for seasonal labor, and (iii) refugees from Ghana who came to Togo because of a communal conflict in Ghana. A questionnaire was designed to collect data on demographics and history of LF and MDA; all participants were tested for circulating filariasis antigen (CFA) using the filariasis test strip (FTS). Any CFA-positive case was confirmed with nocturnal microfilaremia. RESULTS Refugees, seasonal economic migrants and nomadic Peuhls represented 42.1%, 31.4% and 26.5% of the study participants, respectively. The overall prevalence of CFA was 4.2% (58/1391) with the highest prevalence in the nomadic Peuhl group (11.9%), but only one of them (0.07%) was confirmed positive with nocturnal microfilaremia. Using the case investigation algorithm, no other positive case was identified in the positive case's surroundings. CONCLUSION This study demonstrates that nomadic Peuhls, with a CFA prevalence of 11.9%, pose a potential risk for reintroduction of LF into Togo while Ghanaian refugees and seasonal economic migrants do not appear to pose a significant risk. Periodic monitoring of migrants, especially the nomadic Peuhl population, is a potential post-validation surveillance approach that could be used to promptly detect any LF cluster that may arise.
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Affiliation(s)
- Monique Ameyo Dorkenoo
- Université de Lomé, Faculté des Sciences de la Santé, BP 1515 Lomé, Togo
- Programme National d’Elimination de la Filariose Lymphatique, Ministère de la Santé et de l’Hygiène Publique, BP 336 Lomé, Togo
- Division des Laboratoires, Ministère de la Santé et de l’Hygiène Publique, 374 avenue Georges Pompidou, BP 1161 Lomé, Togo
| | | | - Degninou Yehadji
- Division des Laboratoires, Ministère de la Santé et de l’Hygiène Publique, 374 avenue Georges Pompidou, BP 1161 Lomé, Togo
| | - Kossi Yakpa
- Laboratoire de Parasitologie, Programme National de Lutte contre le Paludisme, Ministère de la Santé et de l’Hygiène Publique, Rue Adamé, Quartier administratif BP 518, Lomé, Togo
| | - Mawèké Tchalim
- Programme National d’Elimination de la Filariose Lymphatique, Ministère de la Santé et de l’Hygiène Publique, BP 336 Lomé, Togo
| | - Efoe Sossou
- Division des Laboratoires, Ministère de la Santé et de l’Hygiène Publique, 374 avenue Georges Pompidou, BP 1161 Lomé, Togo
| | - Rachel Bronzan
- Health and Development International (HDI), Newburyport, MA USA
| | - Didier Koumavi Ekouevi
- Université de Lomé, Faculté des Sciences de la Santé, BP 1515 Lomé, Togo
- Centre Africain de Recherche en Epidémiologie et en Santé Publique (CARESP), Lomé, Togo
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Lymphatic filariasis, infection status in Culex quinquefasciatus and Anopheles species after six rounds of mass drug administration in Masasi District, Tanzania. Infect Dis Poverty 2021; 10:20. [PMID: 33648600 PMCID: PMC7919328 DOI: 10.1186/s40249-021-00808-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 02/09/2021] [Indexed: 11/10/2022] Open
Abstract
Background Lymphatic filariasis (LF) elimination program in Tanzania started in 2000 in response to the Global program for the elimination of LF by 2020. Evidence shows a persistent LF transmission despite more than a decade of mass drug administration (MDA). It is advocated that, regular monitoring should be conducted in endemic areas to evaluate the progress towards elimination and detect resurgence of the disease timely. This study was therefore designed to assess the status of Wuchereria bancrofti infection in Culex quinqefasciatus and Anopheles species after six rounds of MDA in Masasi District, South Eastern Tanzania. Methods Mosquitoes were collected between June and July 2019 using Center for Diseases Control (CDC) light traps and gravid traps for indoor and outdoor respectively. The collected mosquitoes were morphologically identified into respective species. Dissections and PCR were carried out to detect W. bancrofti infection. Questionnaire survey and checklist were used to assess vector control interventions and household environment respectively. A Poisson regression model was run to determine the effects of household environment on filarial vector density. Results Overall, 12 452 mosquitoes were collected of which 10 545 (84.7%) were filarial vectors. Of these, Anopheles gambiae complex, An. funestus group and Cx. quinquefasciatus accounted for 0.1%, 0.7% and 99.2% respectively. A total of 365 pools of Cx. quinquefasciatus (each with 20 mosquitoes) and 46 individual samples of Anopheles species were analyzed by PCR. For Cx. quinquefasciatus pools, 33 were positive for W. bancrofti, giving an infection rate of 0.5%, while the 46 samples of Anopheles species were all negative. All 1859 dissected mosquitoes analyzed by microscopy were also negative. Households with modern latrines had less mosquitoes than those with pit latrines [odds ratio (OR) = 0.407, P < 0.05]. Houses with unscreened windows had more mosquitoes as compared to those with screened windows (OR = 2.125, P < 0.05). More than 80% of the participants own bednets while 16.5% had no protection. Conclusions LF low transmission is still ongoing in Masasi District after six rounds of MDA and vector control interventions. The findings also suggest that molecular tools may be essential for xenomonitoring LF transmission during elimination phase. ![]()
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28
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Kwarteng A, Sylverken A, Asiedu E, Ahuno ST. Genome editing as control tool for filarial infections. Biomed Pharmacother 2021; 137:111292. [PMID: 33581654 DOI: 10.1016/j.biopha.2021.111292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 12/26/2022] Open
Abstract
Human filarial infections are vector-borne nematode infections, which include lymphatic filariasis, onchocerciasis, loiasis, and mansonella filariasis. With a high prevalence in developing countries, filarial infections are responsible for some of the most debilitating morbidities and a vicious cycle of poverty and disease. Global initiatives set to eradicate these infections include community mass treatments, vector control, provision of care for morbidity, and search for vaccines. However, there are growing challenges associated with mass treatments, vector control, and antifilarial vaccine development. With the emergence of genome editing tools and successful applications in other infectious diseases, the integration of genetic editing techniques in future control strategies for filarial infections would offer the best option for eliminating filarial infections. In this review, we briefly discuss the mechanisms of the three main genetic editing techniques and explore the potential applications of these powerful tools to control filarial infections.
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Affiliation(s)
- Alexander Kwarteng
- Department of Biochemistry and Biotechnology, Kwame Nkrumah University of Science and Technology, KNUST, Kumasi, Ghana; Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, KNUST, Kumasi, Ghana.
| | - Augustina Sylverken
- Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, KNUST, Kumasi, Ghana; Department of Theoretical and Applied Biology, Kwame Nkrumah University of Science and Technology, KNUST, Kumasi, Ghana
| | - Ebenezer Asiedu
- Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, KNUST, Kumasi, Ghana
| | - Samuel Terkper Ahuno
- Department of Biochemistry and Biotechnology, Kwame Nkrumah University of Science and Technology, KNUST, Kumasi, Ghana; Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, KNUST, Kumasi, Ghana
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29
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Das L, Mathiarasan L, Krishnakumari A. Assessment of the impact of morbidity management and disability prevention for lymphatic filariasis on the disease burden in villupuram district of Tamil Nadu, India. Indian J Community Med 2021; 46:657-661. [PMID: 35068729 PMCID: PMC8729271 DOI: 10.4103/ijcm.ijcm_12_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 09/06/2021] [Indexed: 11/25/2022] Open
Abstract
Background: The global program to eliminate lymphatic filariasis (GPELF) was started in 2003 with two strategies: the mass drug administration (MDA) to interrupt disease transmission and the morbidity management and disability prevention (MMDP) to provide the basic hygienic care to filariasis lymphedema patients. Among the two strategies, the MDA is well advanced and got the desired results, but the MMDP is lagging due to poor execution. Objectives: To assess the awareness of MMDP and ongoing morbidity management practices by lymphedema patients and to estimate the impacts of the MMDP on the prevalence and severity of lymphedema. Materials and Methods: This study was conducted among 100 lymphedema patients in 7 filariasis endemic villages of Villupuram district, Tamil Nadu, India through interviews using a structured, pretested questionnaire. The grading and adenolymphangitis (ADL) attack determination were done by a clinician. The impact was assessed in terms of changes in the lymphedema grades, frequency of ADL attacks, and changes in the burden. Results: Of the 100 patients, 70% were aware of the program and among them, only 48% were practising MMDP regularly (i.e. two times per day). The majority of them (80%) were taking treatment during ADL attacks. The overall lymphedema grades reversal and progression were observed in 13% and 52% of cases, respectively. Conclusion: This study has revealed that the second arm of the GPELF, “MMDP” has not yielded the desired results as evidenced by the incidence of frequent ADL attacks and advancement of lymphedema grades.
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30
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Turner HC. Health economic analyses of the Global Programme to Eliminate Lymphatic Filariasis. Int Health 2020; 13:S71-S74. [PMID: 33349885 PMCID: PMC7753169 DOI: 10.1093/inthealth/ihaa095] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 07/30/2020] [Accepted: 11/19/2020] [Indexed: 11/14/2022] Open
Abstract
The Global Programme to Eliminate Lymphatic Filariasis (GPELF) was established by the WHO in 2000. It aims to eliminate lymphatic filariasis as a public health problem. This paper summarises the key estimates of the cost-effectiveness and economic benefits related to the mass drug administration (MDA) provided by the GPELF. Several studies have investigated the cost-effectiveness of this MDA, estimating the cost per disability-adjusted life year (DALY) averted. These cost-effectiveness estimates have consistently classed the intervention as cost-effective and as favourable compared with other public health interventions conducted in low- and middle-income countries. Studies have also found that the MDA used for lymphatic filariasis control generates significant economic benefits. Although these studies are positive, there are still important gaps that warrant further health economic research (particularly, the evaluation of alternative interventions, further evaluation of morbidity management strategies and evaluation of interventions for settings coendemic with Loa loa). To conclude, health economic studies for a programme as large as the GPELF are subject to uncertainty. That said, the GPELF has consistently been estimated to be cost-effective and to generate notable economic benefits by a number of independent studies.
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Affiliation(s)
- Hugo C Turner
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London, Norfolk Place, London, W2 1PG, UK
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Navarro-Payá D, Flis I, Anderson MAE, Hawes P, Li M, Akbari OS, Basu S, Alphey L. Targeting female flight for genetic control of mosquitoes. PLoS Negl Trop Dis 2020; 14:e0008876. [PMID: 33270627 PMCID: PMC7714197 DOI: 10.1371/journal.pntd.0008876] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 10/12/2020] [Indexed: 01/04/2023] Open
Abstract
Aedes aegypti Act4 is a paralog of the Drosophila melanogaster indirect flight muscle actin gene Act88F. Act88F has been shown to be haploinsufficient for flight in both males and females (amorphic mutants are dominant). Whereas Act88F is expressed in indirect flight muscles of both males and females, expression of Act4 is substantially female-specific. We therefore used CRISPR/Cas9 and homology directed repair to examine the phenotype of Act4 mutants in two Culicine mosquitoes, Aedes aegypti and Culex quinquefasciatus. A screen for dominant female-flightless mutants in Cx. quinquefasciatus identified one such mutant associated with a six base pair deletion in the CxAct4 coding region. A similar screen in Ae. aegypti identified no dominant mutants. Disruption of the AeAct4 gene by homology-dependent insertion of a fluorescent protein marker cassette gave a recessive female-flightless phenotype in Ae. aegypti. Reproducing the six-base deletion from Cx. quinquefasciatus in Ae. aegypti using oligo-directed mutagenesis generated dominant female-flightless mutants and identified additional dominant female-flightless mutants with other in-frame insertions or deletions. Our data indicate that loss of function mutations in the AeAct4 gene are recessive but that short in-frame deletions produce dominant-negative versions of the AeAct4 protein that interfere with flight muscle function. This makes Act4 an interesting candidate for genetic control methods, particularly population-suppression gene drives targeting female viability/fertility.
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Affiliation(s)
| | - Ilona Flis
- Arthropod Genetics, The Pirbright Institute, Pirbright, United Kingdom
| | | | - Philippa Hawes
- Bioimaging, The Pirbright Institute, Pirbright, United Kingdom
| | - Ming Li
- Cell and Developmental Biology Section, Division of Biological Sciences, University of California, San Diego, California, United States of America
| | - Omar S. Akbari
- Cell and Developmental Biology Section, Division of Biological Sciences, University of California, San Diego, California, United States of America
| | - Sanjay Basu
- Arthropod Genetics, The Pirbright Institute, Pirbright, United Kingdom
| | - Luke Alphey
- Arthropod Genetics, The Pirbright Institute, Pirbright, United Kingdom
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Paulo R, Brito M, Van-Dunem P, Martins A, Novak RJ, Jacob B, Molyneux DM, Unnasch TR, Stothard JR, Kelly-Hope L. Clinical, serological and DNA testing in Bengo Province, Angola further reveals low filarial endemicity and opportunities for disease elimination. Parasite Epidemiol Control 2020; 11:e00183. [PMID: 33072898 PMCID: PMC7548300 DOI: 10.1016/j.parepi.2020.e00183] [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: 06/16/2020] [Revised: 07/31/2020] [Accepted: 09/20/2020] [Indexed: 12/05/2022] Open
Abstract
The prevalence of Loa loa, Onchocerca volvulus and Wuchereria bancrofti infections in an under-surveyed area of Bengo Province, Angola, was determined by surveying 22 communities with a combination of clinical, serological and DNA diagnostics. Additional information was collected on participants' duration of residency, access to mass drug administration, knowledge of insect vectors and use of bednets. A total of 1616 individuals (38.1% male: 61.9% female), with an average age of 43 years, were examined. For L. loa, 6.2% (n = 100/16616) individuals were found to have eyeworm, based on the rapid assessment procedure for loiasis (RAPLOA) surveys, and 11.5% (n =178/1543) based on nested PCR analyses of venous blood. L. loa prevalences in long-term residents (>10 years) and older individuals (>60 years) were significantly higher, and older men with eyeworm were better informed about Chrysops vectors. For O. volvulus, 4.7% (n = 74/1567) individuals were found to be positive by enzyme-linked immunosorbent assay (Ov 16 ELISA), with only three individuals reporting to have ever taken ivermectin. For W. bancrofti, no infections were found using the antigen-based immunochromatographic test (ICT) and real-time PCR analysis; however, 27 individuals presented with lymphatic filariasis (LF) related clinical conditions (lymphoedema = 11, hydrocoele = 14, both = 2). Just under half (45.5%) of the participants owned a bednet, with the majority (71.1%) sleeping under it the night before. Our approach of using combination diagnostics reveals the age-prevalence of loiasis alongside low endemicity of onchocerciasis and LF. Future research foci should be on identifying opportunities for more cost-effective ways to eliminate onchocerciasis and to develop innovative surveillance modalities for clinical LF for individual disease management and disability prevention.
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Affiliation(s)
- Rossely Paulo
- Centro de Investigacao em Saude de Angola(CISA)/Health Research Centre of Angola, Caxito, Angola
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Miguel Brito
- Centro de Investigacao em Saude de Angola(CISA)/Health Research Centre of Angola, Caxito, Angola
- Health and Technology Research Center (H&TRC), Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, Portugal
| | - Pedro Van-Dunem
- National Directorate of Public Health, Ministry of Health, Angola
| | - António Martins
- Centro de Investigacao em Saude de Angola(CISA)/Health Research Centre of Angola, Caxito, Angola
| | - Robert J. Novak
- College of Public Health, University of South Florida, Florida, USA
| | - Benjamin Jacob
- College of Public Health, University of South Florida, Florida, USA
| | - David M. Molyneux
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - J. Russell Stothard
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Louise Kelly-Hope
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, UK
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Statistical methods for linking geostatistical maps and transmission models: Application to lymphatic filariasis in East Africa. Spat Spatiotemporal Epidemiol 2020; 41:100391. [PMID: 35691660 PMCID: PMC9205338 DOI: 10.1016/j.sste.2020.100391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 11/06/2020] [Accepted: 11/06/2020] [Indexed: 11/30/2022]
Abstract
Novel methodology for combining geostatistical mapping and transmission modelling. Guide the planning of spatial control programmes by identifying affected areas. Current intervention strategy will not be sufficient to eliminate LF in most areas. Alternative strategies will be required to accelerate LF elimination in East Africa.
Infectious diseases remain one of the major causes of human mortality and suffering. Mathematical models have been established as an important tool for capturing the features that drive the spread of the disease, predicting the progression of an epidemic and hence guiding the development of strategies to control it. Another important area of epidemiological interest is the development of geostatistical methods for the analysis of data from spatially referenced prevalence surveys. Maps of prevalence are useful, not only for enabling a more precise disease risk stratification, but also for guiding the planning of more reliable spatial control programmes by identifying affected areas. Despite the methodological advances that have been made in each area independently, efforts to link transmission models and geostatistical maps have been limited. Motivated by this fact, we developed a Bayesian approach that combines fine-scale geostatistical maps of disease prevalence with transmission models to provide quantitative, spatially-explicit projections of the current and future impact of control programs against a disease. These estimates can then be used at a local level to identify the effectiveness of suggested intervention schemes and allow investigation of alternative strategies. The methodology has been applied to lymphatic filariasis in East Africa to provide estimates of the impact of different intervention strategies against the disease.
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Evaluation of Actin-1 Expression in Wild Caught Wuchereria bancrofti-Infected Mosquito Vectors. J Pathog 2020; 2020:7912042. [PMID: 33062336 PMCID: PMC7547363 DOI: 10.1155/2020/7912042] [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: 11/20/2019] [Revised: 03/18/2020] [Accepted: 03/30/2020] [Indexed: 11/17/2022] Open
Abstract
Background Wuchereria bancrofti is the major cause of lymphatic filariasis transmitted by mosquito vectors. In the vector-parasite interaction and among other proteins, actin-1 has been implicated for successful transmission of the pathogen in laboratory-controlled experiments. However, validation of this finding from the pathogen's natural environment is required. Objective This study is aimed at evaluating actin-1 expression upon Wuchereria bancrofti infection in mosquito vectors collected during an epidemiology study in Tsafe Local Government Area of Zamfara State, Nigeria. Methods Mosquitoes were collected and identified using morphological keys, which include length of maxillary palps, pale spots on the wings, and scale patterns on the abdomen. This was followed by detection of the 188 bp SspI marker of Wuchereria bancrofti infection using polymerase chain reaction (PCR). The mRNA levels of the actin-1 gene were evaluated in the infected Anopheles gambiae sl and Culex quinquefasciatus and their controls, which were adult reared from the larvae in the study area. Results The mosquitoes were identified to be Anopheles gambiae sl and Culex quinquefasciatus, while infection by Wuchereria bancrofti was confirmed by amplification of the 188 bp SspI marker. A 4.85 and 4.09 relative fold increase in actin-1 gene expression in Wuchereria bancrofti-infected Anopheles gambiae sl and Culex quinquefasciatus was observed. Thus, for the first time we reported that the actin-1 gene in wild caught mosquito vectors (Anopheles gambiae sl and Culex quinquefasciatus) infected with Wuchereria bancrofti is upregulated. Conclusion The actin-1 gene is upregulated and similarly expressed during W. bancrofti infection in mosquito vectors in the study area and this may likely serve as a biomarker and viable strategy for the control of parasite transmission in endemic areas.
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Smith ME, Griswold E, Singh BK, Miri E, Eigege A, Adelamo S, Umaru J, Nwodu K, Sambo Y, Kadimbo J, Danyobi J, Richards FO, Michael E. Predicting lymphatic filariasis elimination in data-limited settings: A reconstructive computational framework for combining data generation and model discovery. PLoS Comput Biol 2020; 16:e1007506. [PMID: 32692741 PMCID: PMC7394457 DOI: 10.1371/journal.pcbi.1007506] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 07/31/2020] [Accepted: 05/12/2020] [Indexed: 11/25/2022] Open
Abstract
Although there is increasing importance placed on the use of mathematical models for the effective design and management of long-term parasite elimination, it is becoming clear that transmission models are most useful when they reflect the processes pertaining to local infection dynamics as opposed to generalized dynamics. Such localized models must also be developed even when the data required for characterizing local transmission processes are limited or incomplete, as is often the case for neglected tropical diseases, including the disease system studied in this work, viz. lymphatic filariasis (LF). Here, we draw on progress made in the field of computational knowledge discovery to present a reconstructive simulation framework that addresses these challenges by facilitating the discovery of both data and models concurrently in areas where we have insufficient observational data. Using available data from eight sites from Nigeria and elsewhere, we demonstrate that our data-model discovery system is able to estimate local transmission models and missing pre-control infection information using generalized knowledge of filarial transmission dynamics, monitoring survey data, and details of historical interventions. Forecasts of the impacts of interventions carried out in each site made by the models estimated using the reconstructed baseline data matched temporal infection observations and provided useful information regarding when transmission interruption is likely to have occurred. Assessments of elimination and resurgence probabilities based on the models also suggest a protective effect of vector control against the reemergence of LF transmission after stopping drug treatments. The reconstructive computational framework for model and data discovery developed here highlights how coupling models with available data can generate new knowledge about complex, data-limited systems, and support the effective management of disease programs in the face of critical data gaps. As modelling becomes commonly used in the design and evaluation of parasite elimination programs, the need for well-defined models and datasets describing the nature of transmission processes in local settings is becoming pronounced. For many neglected tropical diseases, however, data for site-specific model identification are typically sparse or incomplete. In this study, we present a new data-model computational discovery system that couples data-assimilation methods based on existing monitoring survey data with model-generated data about baseline conditions to discover the local transmission models required for simulating the impacts of interventions in typical endemic locations for the macroparasitic disease, lymphatic filariasis (LF). Using data from eight study sites in Nigeria and elsewhere, we show that our reconstructive computational framework is able to combine information contained within partially-available site-specific monitoring data with knowledge of parasite transmission dynamics embedded in process-based models to generate the missing data required for inducing reliable locally applicable LF models. We also show that the models so discovered are able to generate the intervention forecasts required for supporting management-relevant decisions in parasite elimination.
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Affiliation(s)
- Morgan E. Smith
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Emily Griswold
- The Carter Center, One Copenhill, Atlanta, Georgia, United States of America
| | - Brajendra K. Singh
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | | | | | | | | | | | | | | | - Jacob Danyobi
- Nasarawa State Ministry of Health, Lafia, Nasarawa, Nigeria
| | - Frank O. Richards
- The Carter Center, One Copenhill, Atlanta, Georgia, United States of America
| | - Edwin Michael
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
- * E-mail:
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Yokoly FN, Zahouli JBZ, Méite A, Opoku M, Kouassi BL, de Souza DK, Bockarie M, Koudou BG. Low transmission of Wuchereria bancrofti in cross-border districts of Côte d'Ivoire: A great step towards lymphatic filariasis elimination in West Africa. PLoS One 2020; 15:e0231541. [PMID: 32282840 PMCID: PMC7153895 DOI: 10.1371/journal.pone.0231541] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 03/25/2020] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Lymphatic filariasis (LF) is widely endemic in Côte d'Ivoire, and elimination as public health problem (EPHP) is based on annual mass drug administration (MDA) using ivermectin and albendazole. To guide EPHP efforts, we evaluated Wuchereria bancrofti infection indices among humans, and mosquito vectors after four rounds of MDA in four cross-border health districts of Côte d'Ivoire. METHODOLOGY We monitored people and mosquitoes for W. bancrofti infections in the cross-border health districts of Aboisso, Bloléquin, Odienné and Ouangolodougou, Côte d'Ivoire. W. bancrofti circulating filarial antigen (CFA) was identified using filariasis test strips, and antigen-positive individuals were screened for microfilaremia. Moreover, filarial mosquito vectors were sampled using window exit traps and pyrethrum sprays, and identified morphologically at species level. Anopheles gambiae s.l. and Culex quinquefasciatus females were analyzed for W. bancrofti infection using polymerase chain reaction (PCR) technique. PRINCIPAL FINDINGS Overall, we found a substantial decline in W. bancrofti infection indices after four rounds of MDA compared to pre-MDA baseline data. CFA prevalence fell from 3.38-5.50% during pre-MDA to 0.00-1.53% after MDA interventions. No subjects had detectable levels of CFA in Ouangolodougou. Moreover, post-MDA CFA prevalence was very low, and below the 1% elimination threshold in Aboisso (0.19%) and Odienné (0.49%). Conversely, CFA prevalence remained above 1% in Bloléquin (1.53%). W. bancrofti microfilariae (Mf) were not found in Aboisso, Bloléquin, and Ouangolodougou, except for Odienné with low prevalence (0.16%; n = 613) and microfilaremia of 32.0 Mf/mL. No An. gambiae s.l. and Cx. quinquefasciatus pools were infected with W. bancrofti in Bloléquin and Ouangolodougou, while they exhibited low infection rates in Aboisso (1% and 0.07%), and Odienné (0.08% and 0.08%), respectively. CONCLUSIONS In cross-border areas of Côte d'Ivoire, LF infection indices in humans and mosquito vectors substantially declined after four rounds of MDA. CFA prevalence fell under the World Health Organization (WHO)-established threshold (1%) in Aboisso, Ouangolodougou and Odienné. Moreover, W. bancrofti prevalence in mosquitoes was lower than WHO-established threshold (2%) in all areas. This might suggest the interruption of W. bancrofti transmission, and possible MDA cessation. However, a formal transmission assessment survey (TAS) and molecular xenomonitoring in mosquito vectors should be implemented before eventual MDA cessation. However, MDA should pursue in Bloléquin where W. bancrofti infection prevalence remained above 1%. Our results provided important ramifications for LF control efforts towards EPHP in Côte d'Ivoire.
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Affiliation(s)
- Firmain N. Yokoly
- Unité de Formation et de Recherche Sciences de la Nature, Université Nangui Abrogoua, Abidjan, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Julien B. Z. Zahouli
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Centre d’Entomologie Médicale et Vétérinaire, Université Alassane Ouattara, Bouaké, Côte d’Ivoire
| | - Aboulaye Méite
- Programme National de Lutte contre les Maladies Tropicales Négligées à Chimiothérapie Préventive, Ministère de la Santé, Abidjan, Côte d’Ivoire
| | - Millicent Opoku
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
- European & Developing Countries Clinical Trials Partnership, Cape Town, South Africa
| | - Bernard L. Kouassi
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Dziedzom K. de Souza
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana
| | - Moses Bockarie
- European & Developing Countries Clinical Trials Partnership, Cape Town, South Africa
- Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Benjamin G. Koudou
- Unité de Formation et de Recherche Sciences de la Nature, Université Nangui Abrogoua, Abidjan, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
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Michael E, Smith ME, Singh BK, Katabarwa MN, Byamukama E, Habomugisha P, Lakwo T, Tukahebwa E, Richards FO. Data-driven modelling and spatial complexity supports heterogeneity-based integrative management for eliminating Simulium neavei-transmitted river blindness. Sci Rep 2020; 10:4235. [PMID: 32144362 PMCID: PMC7060237 DOI: 10.1038/s41598-020-61194-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 02/24/2020] [Indexed: 11/28/2022] Open
Abstract
Concern is emerging regarding the challenges posed by spatial complexity for modelling and managing the area-wide elimination of parasitic infections. While this has led to calls for applying heterogeneity-based approaches for addressing this complexity, questions related to spatial scale, the discovery of locally-relevant models, and its interaction with options for interrupting parasite transmission remain to be resolved. We used a data-driven modelling framework applied to infection data gathered from different monitoring sites to investigate these questions in the context of understanding the transmission dynamics and efforts to eliminate Simulium neavei- transmitted onchocerciasis, a macroparasitic disease that causes river blindness in Western Uganda and other regions of Africa. We demonstrate that our Bayesian-based data-model assimilation technique is able to discover onchocerciasis models that reflect local transmission conditions reliably. Key management variables such as infection breakpoints and required durations of drug interventions for achieving elimination varied spatially due to site-specific parameter constraining; however, this spatial effect was found to operate at the larger focus level, although intriguingly including vector control overcame this variability. These results show that data-driven modelling based on spatial datasets and model-data fusing methodologies will be critical to identifying both the scale-dependent models and heterogeneity-based options required for supporting the successful elimination of S. neavei-borne onchocerciasis.
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Affiliation(s)
- Edwin Michael
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA.
| | - Morgan E Smith
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Brajendra K Singh
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Moses N Katabarwa
- The Carter Center, One Copenhill, 453 Freedom Parkway, Atlanta, GA, 30307, USA
| | - Edson Byamukama
- The Carter Center, Uganda, 15 Bombo Road, P.O. Box, 12027, Kampala, Uganda
| | - Peace Habomugisha
- The Carter Center, Uganda, 15 Bombo Road, P.O. Box, 12027, Kampala, Uganda
| | - Thomson Lakwo
- Vector Control Division, Ministry of Health, 15 Bombo Road, P.O. Box, 1661, Kampala, Uganda
| | - Edridah Tukahebwa
- Vector Control Division, Ministry of Health, 15 Bombo Road, P.O. Box, 1661, Kampala, Uganda
| | - Frank O Richards
- The Carter Center, One Copenhill, 453 Freedom Parkway, Atlanta, GA, 30307, USA
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Mosquito diversity and dog heartworm prevalence in suburban areas. Parasit Vectors 2020; 13:12. [PMID: 31924253 PMCID: PMC6953185 DOI: 10.1186/s13071-019-3874-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 12/30/2019] [Indexed: 01/27/2023] Open
Abstract
Background Urbanization is occurring rapidly on a global scale and is altering mosquito communities, creating assemblages that are characteristically less diverse. Despite high rates of urbanization and ample examples of vector-borne diseases transmitted by multiple species, the effects of urbanization-driven mosquito diversity losses on disease transmission has not been well explored. We investigated this question using the dog heartworm, a filarial parasite vectored by numerous mosquito species. Methods We trapped host-seeking mosquitoes in undeveloped areas and neighborhoods of different ages in Wake County, North Carolina, USA, analyzing captured mosquitoes for heartworm DNA. We compared within-mosquito heartworm infection across land-use types by Kruskal–Wallis and likelihood ratio tests. Using zip code level data acquired from dogs in a local shelter, we performed linear regressions of within-host heartworm prevalence by within-mosquito heartworm prevalence as well as by three mosquito diversity measures. We also determined the best predictor of host-level prevalence among models including within-mosquito infection, mosquito diversity and abundance, and socioeconomic status as variables. Results Suburban areas had lower within-mosquito heartworm prevalence and lower likelihood of heartworm-positive mosquitoes than did undeveloped field sites, although no differences were seen between suburban and undeveloped wooded sites. No relationships were noted between within-mosquito and within-host heartworm prevalence. However, mosquito diversity metrics were positively correlated with host heartworm prevalence. Model selection revealed within-host prevalence was best predicted by a positive relationship with mosquito Shannon–Wiener diversity and a negative relationship with household income. Conclusions Our results demonstrate that decreases in mosquito diversity due to urbanization alter vector-borne disease risk. With regard to dog heartworm disease, this loss of mosquito diversity is associated with decreased heartworm prevalence within both the vector and the host. Although the response is likely different for diseases transmitted by one or few species, mosquito diversity losses leading to decreased transmission could be generalizable to other pathogens with multiple vectors. This study contributes to better understanding of the effects of urbanization and the role of vector diversity in multi-vectored pathosystems.![]()
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Wilson AL, Courtenay O, Kelly-Hope LA, Scott TW, Takken W, Torr SJ, Lindsay SW. The importance of vector control for the control and elimination of vector-borne diseases. PLoS Negl Trop Dis 2020; 14:e0007831. [PMID: 31945061 PMCID: PMC6964823 DOI: 10.1371/journal.pntd.0007831] [Citation(s) in RCA: 288] [Impact Index Per Article: 72.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Vector-borne diseases (VBDs) such as malaria, dengue, and leishmaniasis exert a huge burden of morbidity and mortality worldwide, particularly affecting the poorest of the poor. The principal method by which these diseases are controlled is through vector control, which has a long and distinguished history. Vector control, to a greater extent than drugs or vaccines, has been responsible for shrinking the map of many VBDs. Here, we describe the history of vector control programmes worldwide from the late 1800s to date. Pre 1940, vector control relied on a thorough understanding of vector ecology and epidemiology, and implementation of environmental management tailored to the ecology and behaviour of local vector species. This complex understanding was replaced by a simplified dependency on a handful of insecticide-based tools, particularly for malaria control, without an adequate understanding of entomology and epidemiology and without proper monitoring and evaluation. With the rising threat from insecticide-resistant vectors, global environmental change, and the need to incorporate more vector control interventions to eliminate these diseases, we advocate for continued investment in evidence-based vector control. There is a need to return to vector control approaches based on a thorough knowledge of the determinants of pathogen transmission, which utilise a range of insecticide and non-insecticide-based approaches in a locally tailored manner for more effective and sustainable vector control.
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Affiliation(s)
- Anne L. Wilson
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Orin Courtenay
- Zeeman Institute and School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Louise A. Kelly-Hope
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Thomas W. Scott
- Department of Entomology and Nematology, University of California Davis, Davis, California, United States of America
| | - Willem Takken
- Department of Plant Sciences, Wageningen University and Research, Wageningen, the Netherlands
| | - Steve J. Torr
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Steve W. Lindsay
- Department of Biosciences, Durham University, Durham, United Kingdom
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Somerville AGT, Gleave K, Jones CM, Reimer LJ. The consequences of Brugia malayi infection on the flight and energy resources of Aedes aegypti mosquitoes. Sci Rep 2019; 9:18449. [PMID: 31804546 PMCID: PMC6895159 DOI: 10.1038/s41598-019-54819-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 11/14/2019] [Indexed: 12/19/2022] Open
Abstract
Evidence from experimental infection studies has shown that infected mosquitoes exhibit altered host-seeking behaviours, with suppression and activation of behaviours dependent on the parasite's development stage. The mechanisms are poorly characterised; however, infections can impact mosquito energy reserves, thereby influencing key life-history traits and behaviours. In addition, filarial infection is likely detrimental to flight due to damage caused by developing worms. This study aimed to evaluate the impacts of Brugia malayi infection on Aedes aegypti flight parameters: distance, average speed, maximum speed and number of flight bursts, using a tethered flight mill. In addition, we explored whether differences in flight capacity may be due to the effect of infection on glycogen and lipid reserves. Infection with filarial worms significantly reduced flight distance but increased the number of flight bursts. Exposure to microfilaermic blood led to a significant decrease in average and maximum flight speeds even in the absence of an established infection. Mosquitoes fed on microfilaraemic blood showed reduced levels of glycogen (-37.9%) and lipids (-49.7%) compared to controls at nine days post-exposure. However, a one-hour period of flight activity caused an increase in lipid content for both infected and control mosquitoes. Consequential flight incapacitation may serve in explaining the heterogeneous distribution of lymphatic filariasis.
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Affiliation(s)
| | - Katherine Gleave
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Christopher M Jones
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Lisa J Reimer
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
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Smith ME, Bilal S, Lakwo TL, Habomugisha P, Tukahebwa E, Byamukama E, Katabarwa MN, Richards FO, Cupp EW, Unnasch TR, Michael E. Accelerating river blindness elimination by supplementing MDA with a vegetation "slash and clear" vector control strategy: a data-driven modeling analysis. Sci Rep 2019; 9:15274. [PMID: 31649285 PMCID: PMC6813336 DOI: 10.1038/s41598-019-51835-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 10/09/2019] [Indexed: 01/08/2023] Open
Abstract
Attention is increasingly focusing on how best to accelerate progress toward meeting the WHO's 2030 goals for neglected tropical diseases (NTDs). For river blindness, a major NTD targeted for elimination, there is a long history of using vector control to suppress transmission, but traditional larvicide-based approaches are limited in their utility. One innovative and sustainable approach, "slash and clear", involves clearing vegetation from breeding areas, and recent field trials indicate that this technique very effectively reduces the biting density of Simulium damnosum s.s. In this study, we use a Bayesian data-driven mathematical modeling approach to investigate the potential impact of this intervention on human onchocerciasis infection. We developed a novel "slash and clear" model describing the effect of the intervention on seasonal black fly biting rates and coupled this with our population dynamics model of Onchocerca volvulus transmission. Our results indicate that supplementing annual drug treatments with "slash and clear" can significantly accelerate the achievement of onchocerciasis elimination. The efficacy of the intervention is not very sensitive to the timing of implementation, and the impact is meaningful even if vegetation is cleared only once per year. As such, this community-driven technique will represent an important option for achieving and sustaining O. volvulus elimination.
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Affiliation(s)
- Morgan E Smith
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Shakir Bilal
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Thomson L Lakwo
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | | | | | | | | | | | - Eddie W Cupp
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, USA
| | - Thomas R Unnasch
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, USA
| | - Edwin Michael
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA.
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Fang Y, Zhang Y. Lessons from lymphatic filariasis elimination and the challenges of post-elimination surveillance in China. Infect Dis Poverty 2019; 8:66. [PMID: 31387644 PMCID: PMC6685173 DOI: 10.1186/s40249-019-0578-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 07/12/2019] [Indexed: 11/23/2022] Open
Abstract
Background The Global Programme to Eliminate Lymphatic Filariasis (GPELF) was launched in response to the call proposed at the 50th World Health Assembly. The goal of the GPELF is to ensure that all the countries where the disease is endemic would have been transmission-free or would have entered post-intervention mass drug administration (MDA) surveillance by 2020. However, several countries are still not on track to discontinue MDA as planned. Thus, issues remain regarding the achievement of stated goals and how to effectively monitor the disease in the post-control and post-elimination phases. Main text China was once a lymphatic filariasis (LF) endemic country with heavy disease burden. There were three milestones in the LF control phase of China, including: the proposal that the major focus of the control strategy should be on infectious sources; the three regimens of diethylcarbamazine (DEC) administration according to LF endemic extent; and the establishment of the threshold for LF transmission interruption. It has been ten years since China entered the post-elimination stage (declaration of LF elimination in China was in 2007). Two schemes and a diagnostic criterion were issued to guide all levels of disease control and prevention workers that conduct LF surveillance, as well as those caring for chronic filariasis patients. Regular training courses are held to maintain LF control skills in grass-root institutions. The Notifiable Diseases Reporting System, which included LF in 2004, plays an important role in LF post-elimination surveillance. Until now, no resurgence of LF cases has been detected, except for LF residue foci being found in Fuchuan County of the Guangxi Zhuang Autonomous Region. To confirm that transmission is no longer achievable after a decade since the declaration of LF elimination in China, it is expected within the next two years a transmission assessment survey, conducted in previous LF-endemic areas. Conclusions DEC-fortified salt can help accelerate the progress of GPELF before the sprite phase. Sophisticated diagnostic criteria, systematic surveillance regimes, the Direct Network Report system, and regular trainings can effectively prevent the recrudescence of LF during surveillance phases. Electronic supplementary material The online version of this article (10.1186/s40249-019-0578-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yuan Fang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Diseases Research, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasite and Vector Biology, Ministry of Health, 207 Ruijin Er Road, Shanghai, 200025, People's Republic of China
| | - Yi Zhang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Diseases Research, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasite and Vector Biology, Ministry of Health, 207 Ruijin Er Road, Shanghai, 200025, People's Republic of China.
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Transcriptomic analysis of insecticide resistance in the lymphatic filariasis vector Culex quinquefasciatus. Sci Rep 2019; 9:11406. [PMID: 31388075 PMCID: PMC6684662 DOI: 10.1038/s41598-019-47850-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 07/25/2019] [Indexed: 11/08/2022] Open
Abstract
Culex quinquefasciatus plays an important role in transmission of vector-borne diseases of public health importance, including lymphatic filariasis (LF), as well as many arboviral diseases. Currently, efforts to tackle C. quinquefasciatus vectored diseases are based on either mass drug administration (MDA) for LF, or insecticide-based interventions. Widespread and intensive insecticide usage has resulted in increased resistance in mosquito vectors, including C. quinquefasciatus. Herein, the transcriptome profile of Ugandan bendiocarb-resistant C. quinquefasciatus was explored to identify candidate genes associated with insecticide resistance. High levels of insecticide resistance were observed for five out of six insecticides tested, with the lowest mortality (0.97%) reported to permethrin, while for DDT, lambdacyhalothrin, bendiocarb and deltamethrin the mortality rate ranged from 1.63-3.29%. Resistance to bendiocarb in exposed mosquitoes was marked, with 2.04% mortality following 1 h exposure and 58.02% after 4 h. Genotyping of the G119S Ace-1 target site mutation detected a highly significant association (p < 0.0001; OR = 25) between resistance and Ace1-119S. However, synergist assays using the P450 inhibitor PBO, or the esterase inhibitor TPP resulted in markedly increased mortality (to ≈80%), suggesting a role of metabolic resistance in the resistance phenotype. Using a novel, custom 60 K whole-transcriptome microarray 16 genes significantly overexpressed in resistant mosquitoes were detected, with the P450 Cyp6z18 showing the highest differential gene expression (>8-fold increase vs unexposed controls). These results provide evidence that bendiocarb resistance in Ugandan C. quinquefasciatus is mediated by both target-site mechanisms and over-expression of detoxification enzymes.
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Chami GF, Bundy DAP. More medicines alone cannot ensure the treatment of neglected tropical diseases. THE LANCET. INFECTIOUS DISEASES 2019; 19:e330-e336. [PMID: 31160190 DOI: 10.1016/s1473-3099(19)30160-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 02/15/2019] [Accepted: 03/13/2019] [Indexed: 01/19/2023]
Abstract
Neglected tropical diseases afflict more than 1 billion of the world's poorest people. Pharmaceutical donations of preventive chemotherapy for neglected tropical diseases enable the largest en masse treatment campaigns globally with respect to the number of people targeted for treatment. However, the blanket distribution of medicines at no cost to individuals in need of treatment does not guarantee that those individuals are treated. In this Personal View, we aim to examine the next steps that need to be taken towards ensuring equitable treatment access, including health system integration and the role of endemic countries in ensuring medicines are delivered to patients. We argue that the expansion of medicine donation programmes and the development of new medicines are not the primary solutions to sustaining and expanding the growth of neglected tropical disease programmes. Treatment is often not verified by a medical professional, independent surveyor, or national programme officer. Additionally, access to medicines might not be equitable across at-risk populations, and treatment targets for disease control remain largely unmet within many endemic countries. To enable equitable access and efficient use of existing medicines, research is needed now on how best to integrate the treatment of neglected tropical diseases into local health systems. A comprehensive approach should be used, which combines mass drug administration with on-demand access to treatment. Increased commitment by endemic countries, when possible, around the ownership of treatment campaigns is essential to improve access to medicines for neglected tropical diseases.
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Affiliation(s)
- Goylette F Chami
- Department of Pathology, University of Cambridge, Cambridge, UK.
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Boko-Collins PM, Ogouyemi-Hounto A, Adjinacou-Badou EG, Gbaguidi-Saizonou L, Dossa NI, Dare A, Ibikounle M, Zoerhoff KL, Cohn DA, Batcho W. Assessment of treatment impact on lymphatic filariasis in 13 districts of Benin: progress toward elimination in nine districts despite persistence of transmission in some areas. Parasit Vectors 2019; 12:276. [PMID: 31146779 PMCID: PMC6543600 DOI: 10.1186/s13071-019-3525-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 05/23/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Lymphatic filariasis (LF) is still a public health burden in many developing countries. In Benin, a West African country, at least 6.6 million people are at risk for LF. With the goal of eliminating LF by 2020, mass drug administration (MDA) has been scaled-up during the last decade. Currently, 23 districts are believed to have eliminated LF as a public health problem, and 25 other districts are still under treatment. In this study we report the results of the first transmission assessment survey of LF (TAS1) in 13 districts from the second group, which have received at least six rounds of MDA with albendazole and ivermectin. METHODS The 13 districts were grouped into six evaluation units (EU). In each EU, 30 schools randomly selected by survey sample builder (SSB) software were surveyed. Children aged six and seven were sampled in schools and for each child the Alere™ Filariasis Test Strip test was carried out using finger-prick blood to detect the circulating filarial antigen from Wuchereria bancrofti. RESULTS Overall, 9381 children were sampled in 191 schools from the six EU with 47.6% of the children aged six years and 52.4% aged seven years. Five EU passed the assessment, with no positive cases identified. The EU of Ouinhi which grouped the districts of Ouinhi, Cove, Za-Kpota and Zagnanado failed, with 47 positive cases. These cases were clustered in the districts of Ouinhi (n = 20), Za-Kpota (n = 11) and Zagnanado (n = 16). No cases were found in the district of Cove. CONCLUSIONS The findings of our study indicate that Benin has made important progress towards elimination in most districts evaluated. However, this study also shows that transmission of LF is ongoing in the EU of Ouinhi, part of the Zou department. The MDA strategy needs to be strengthened in order to control the human reservoir of infection in these districts.
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Affiliation(s)
- Pelagie M Boko-Collins
- National Control Program of Communicable Diseases, Ministry of Health of Benin, 01-BP-882, Cotonou, Benin.
| | | | - Elvire G Adjinacou-Badou
- National Control Program of Communicable Diseases, Ministry of Health of Benin, 01-BP-882, Cotonou, Benin
| | - Laurinda Gbaguidi-Saizonou
- National Control Program of Communicable Diseases, Ministry of Health of Benin, 01-BP-882, Cotonou, Benin
| | | | | | - Moudachirou Ibikounle
- Department of Zoology, Faculty of Sciences and Techniques, University of Abomey-Calavi, 01 BP 526, Cotonou, Benin
| | - Kathryn L Zoerhoff
- RTI International, 701 13th Street NW, Suite 750, Washington, DC, 20005, USA
| | - Daniel A Cohn
- RTI International, 701 13th Street NW, Suite 750, Washington, DC, 20005, USA
| | - Wilfrid Batcho
- National Control Program of Communicable Diseases, Ministry of Health of Benin, 01-BP-882, Cotonou, Benin
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46
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Silva Martins WF, Silva Pereira BN, Vieira Alves AT, Murphy A, Silva Martins PG, Weetman D, Wilding CS, Donnelly MJ. Development and application of a tri-allelic PCR assay for screening Vgsc-L1014F kdr mutations associated with pyrethroid and organochlorine resistance in the mosquito Culex quinquefasciatus. Parasit Vectors 2019; 12:232. [PMID: 31088572 PMCID: PMC6518802 DOI: 10.1186/s13071-019-3490-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 05/06/2019] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Culex quinquefasciatus has a widespread distribution across tropical and sub-tropical regions, and plays an important role in the transmission of vector-borne diseases of public health importance, including lymphatic filariasis (LF) and multiple arboviruses. Increased resistance to insecticides threatens the efficacy and sustainability of insecticide-based anti-vector interventions which mitigate the burden of mosquito transmitted diseases in endemic regions. In C. quinquefasciatus two non-synonymous voltage gated sodium channel (Vgsc) variants, both resulting in a leucine to phenylalanine change at codon 1014, are associated with resistance to pyrethroids and DDT. This tri-allelic variation has compromised the ability to perform high-throughput single-assay screening. To facilitate the detection and monitoring of the Vgsc-1014 locus in field-caught mosquitoes, an Engineered-Tail Allele-Specific-PCR (ETAS-PCR) diagnostic assay was developed and applied to wild mosquitoes from Brazil, Tanzania and Uganda. RESULTS This new cost-effective, single-tube assay was compared to two, well-established, genotyping approaches, pyrosequencing and TaqMan. The ETAS-PCR assay showed high specificity for discriminating the three alleles at Vgsc-L1014F, with genotyping results strongly correlated with pyrosequencing and TaqMan results (98.64% and 100% respectively). CONCLUSIONS Our results support the utility of the ETAS-PCR/Vgsc-1014 diagnostic assay, which stands as an effective alternative for genotyping tri-allelic variants.
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Affiliation(s)
- Walter Fabricio Silva Martins
- Laboratório de Entomologia Médica e Molecular, Departamento de Biologia, CCBS, Universidade Estadual da Paraíba, Campina Grande, Paraíba, Brasil
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | | | - Ana Thayse Vieira Alves
- Laboratório de Entomologia Médica e Molecular, Departamento de Biologia, CCBS, Universidade Estadual da Paraíba, Campina Grande, Paraíba, Brasil
- Departamento de Farmácia, CCBS, Universidade Estadual da Paraíba, Campina Grande, Paraíba, Brasil
| | - Annabel Murphy
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Paulo Geovani Silva Martins
- Laboratório de Interações Insetos-Tóxicos, Departamento de Agronomia e Fitossanidade, Universidade Federal Rural de Pernambuco, Recife, Brasil
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Craig Stephen Wilding
- School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, UK
| | - Martin James Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
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47
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Abstract
Lymphatic filariasis (LF) is a parasitic infection that is spread by mosquitos infected with worm larvae. Several factors will affect the global prevalence of LF in the future. A growing body of evidence suggests that climate change will influence the spread of parasitic diseases and their vectors. Lymphatic filariasis is the leading cause of permanent disfigurement and the second most common cause of long-term disability in the world.
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Affiliation(s)
- Gayle B Lourens
- Michigan State University, 1355 Bogue Street, East Lansing, MI 48824, USA.
| | - Denise K Ferrell
- Michigan State University, 1355 Bogue Street, East Lansing, MI 48824, USA
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48
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Pi-Bansa S, Osei JHN, Kartey-Attipoe WD, Elhassan E, Agyemang D, Otoo S, Dadzie SK, Appawu MA, Wilson MD, Koudou BG, de Souza DK, Utzinger J, Boakye DA. Assessing the Presence of Wuchereria bancrofti Infections in Vectors Using Xenomonitoring in Lymphatic Filariasis Endemic Districts in Ghana. Trop Med Infect Dis 2019; 4:tropicalmed4010049. [PMID: 30884886 PMCID: PMC6473662 DOI: 10.3390/tropicalmed4010049] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 03/10/2019] [Accepted: 03/13/2019] [Indexed: 11/23/2022] Open
Abstract
Mass drug administration (MDA) is the current mainstay to interrupt the transmission of lymphatic filariasis. To monitor whether MDA is effective and transmission of lymphatic filariasis indeed has been interrupted, rigorous surveillance is required. Assessment of transmission by programme managers is usually done via serology. New research suggests that xenomonitoring holds promise for determining the success of lymphatic filariasis interventions. The objective of this study was to assess Wuchereria bancrofti infection in mosquitoes as a post-MDA surveillance tool using xenomonitoring. The study was carried out in four districts of Ghana; Ahanta West, Mpohor, Kassena Nankana West and Bongo. A suite of mosquito sampling methods was employed, including human landing collections, pyrethrum spray catches and window exit traps. Infection of W. bancrofti in mosquitoes was determined using dissection, conventional and real-time polymerase chain reaction and loop mediated isothermal amplification assays. Aedes, Anopheles coustani, An. gambiae, An. pharoensis, Culex and Mansonia mosquitoes were sampled in each of the four study districts. The dissected mosquitoes were positive for filarial infection using molecular assays. Dissected An. melas mosquitoes from Ahanta West district were the only species found positive for filarial parasites. We conclude that whilst samples extracted with Trizol reagent did not show any positives, molecular methods should still be considered for monitoring and surveillance of lymphatic filariasis transmission.
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Affiliation(s)
- Sellase Pi-Bansa
- Swiss Tropical and Public Health Institute, CH-4002 Basel, Switzerland.
- University of Basel, CH-4003 Basel, Switzerland.
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, LG 581 Legon, Ghana.
| | - Joseph H N Osei
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, LG 581 Legon, Ghana.
- Department of Animal Biology and Conservation Science, University of Ghana, LG 67 Legon, Ghana.
| | - Worlasi D Kartey-Attipoe
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, LG 581 Legon, Ghana.
| | | | | | - Sampson Otoo
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, LG 581 Legon, Ghana.
| | - Samuel K Dadzie
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, LG 581 Legon, Ghana.
| | - Maxwell A Appawu
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, LG 581 Legon, Ghana.
| | - Michael D Wilson
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, LG 581 Legon, Ghana.
| | - Benjamin G Koudou
- Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK.
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 BP 1303, Abidjan 01, Côte d'Ivoire.
| | - Dziedzom K de Souza
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, LG 581 Legon, Ghana.
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, CH-4002 Basel, Switzerland.
- University of Basel, CH-4003 Basel, Switzerland.
| | - Daniel A Boakye
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, LG 581 Legon, Ghana.
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49
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Pi-Bansa S, Osei JHN, Frempong KK, Elhassan E, Akuoko OK, Agyemang D, Ahorlu C, Appawu MA, Koudou BG, Wilson MD, de Souza DK, Dadzie SK, Utzinger J, Boakye DA. Potential factors influencing lymphatic filariasis transmission in "hotspot" and "control" areas in Ghana: the importance of vectors. Infect Dis Poverty 2019; 8:9. [PMID: 30717788 PMCID: PMC6362603 DOI: 10.1186/s40249-019-0520-1] [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: 08/01/2018] [Accepted: 01/17/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mass drug administration (MDA) programmes for the control of lymphatic filariasis in Ghana, have been ongoing in some endemic districts for 16 years. The current study aimed to assess factors that govern the success of MDA programmes for breaking transmission of lymphatic filariasis in Ghana. METHODS The study was undertaken in two "hotspot" districts (Ahanta West and Kassena Nankana West) and two control districts (Mpohor and Bongo) in Ghana. Mosquitoes were collected and identified using morphological and molecular tools. A proportion of the cibarial armatures of each species was examined. Dissections were performed on Anopheles gambiae for filarial worm detection. A questionnaire was administered to obtain information on MDA compliance and vector control activities. Data were compared between districts to determine factors that might explain persistent transmission of lymphatic filariasis. RESULTS High numbers of mosquitoes were sampled in Ahanta West district compared to Mpohor district (F = 16.09, P = 0.002). There was no significant difference between the numbers of mosquitoes collected in Kassena Nankana West and Bongo districts (F = 2.16, P = 0.185). Mansonia species were predominant in Ahanta West district. An. coluzzii mosquitoes were prevalent in all districts. An. melas with infected and infective filarial worms was found only in Ahanta West district. No differences were found in cibarial teeth numbers and shape for mosquito species in the surveyed districts. Reported MDA coverage was high in all districts. The average use of bednet and indoor residual spraying was 82.4 and 66.2%, respectively. There was high compliance in the five preceding MDA rounds in Ahanta West and Kassena Nankana West districts, both considered hotspots of lymphatic filariasis transmission. CONCLUSIONS The study on persistent transmission of lymphatic filariasis in the two areas in Ghana present information that shows the importance of local understanding of factors affecting control and elimination of lymphatic filariasis. Unlike Kassena Nankana West district where transmission dynamics could be explained by initial infection prevalence and low vector densities, ongoing lymphatic filariasis transmission in Ahanta West district might be explained by high biting rates of An. gambiae and initial infection prevalence, coupled with high densities of An. melas and Mansonia vector species that have low or no teeth and exhibiting limitation.
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Affiliation(s)
- Sellase Pi-Bansa
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland. .,Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana.
| | - Joseph Harold Nyarko Osei
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana.,Department of Animal Biology and Conservation Science, University of Ghana, Legon, Ghana
| | - Kwadwo Kyeremeh Frempong
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana.,Department of Animal Biology and Conservation Science, University of Ghana, Legon, Ghana
| | | | - Osei Kweku Akuoko
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana.,African Regional Postgraduate Programme in Insect Science, University of Ghana, Legon, Ghana
| | | | - Collins Ahorlu
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Maxwell Alexander Appawu
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Benjamin Guibehi Koudou
- Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, UK.,Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire
| | - Michael David Wilson
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Dziedzom Komi de Souza
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Samuel Kweku Dadzie
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Daniel Adjei Boakye
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
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50
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Macfarlane CL, Budhathoki SS, Johnson S, Richardson M, Garner P. Albendazole alone or in combination with microfilaricidal drugs for lymphatic filariasis. Cochrane Database Syst Rev 2019; 1:CD003753. [PMID: 30620051 PMCID: PMC6354574 DOI: 10.1002/14651858.cd003753.pub4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND The Global Programme to Eliminate Lymphatic Filariasis recommends mass treatment of albendazole co-administered with the microfilaricidal (antifilarial) drugs diethylcarbamazine (DEC) or ivermectin; and recommends albendazole alone in areas where loiasis is endemic. OBJECTIVES To assess the effects of albendazole alone, and the effects of adding albendazole to DEC or ivermectin, in people and communities with lymphatic filariasis. SEARCH METHODS We searched the Cochrane Infectious Diseases Group Specialized Register, the Cochrane Central Register of Controlled Trials, MEDLINE (PubMed), Embase (OVID), LILACS (BIREME), and reference lists of included trials. We also searched the World Health Organization (WHO) International Clinical Trials Registry Platform and ClinicalTrials.gov to identify ongoing trials. We performed all searches up to 15 January 2018. SELECTION CRITERIA We included randomized controlled trials (RCTs) and cluster-RCTs that compared albendazole to placebo or no placebo, or compared albendazole combined with a microfilaricidal drug to a microfilaricidal drug alone, given to people known to have lymphatic filariasis or communities where lymphatic filariasis was known to be endemic. We sought data on measures of transmission potential (microfilariae (mf) prevalence and density); markers of adult worm infection (antigenaemia prevalence and density, and adult worm prevalence detected by ultrasound); and data on clinical disease and adverse events. DATA COLLECTION AND ANALYSIS At least two review authors independently assessed the trials, evaluated the risks of bias, and extracted data. The main analysis examined albendazole overall, whether given alone or added to a microfilaricidal drug. We used data collected from all randomized individuals at time of longest follow-up (up to 12 months) for meta-analysis of outcomes. We evaluated mf density data up to six months and at 12 months follow-up to ensure that we did not miss any subtle temporal effects. We conducted additional analyses for different follow-up periods and whether trials reported on individuals known to be infected or both infected and uninfected. We analysed dichotomous data using the risk ratio (RR) with a 95% confidence interval (CI). We could not meta-analyse data on parasite density outcomes and we summarized them in tables. Where data were missing, we contacted trial authors. We used GRADE to assess the certainty of evidence. MAIN RESULTS We included 13 trials (12 individually-randomized and one small cluster-randomized trial) with 8713 participants in total. No trials evaluated population-level effects of albendazole in mass drug administration programmes. Seven trials enrolled people with a variety of inclusion criteria related to filarial infection, and six trials enrolled individuals from endemic areas. Outcomes were reported as end or change values. Mf and antigen density data were reported using the geometric mean, log mean and arithmetic mean, and reductions in density were variously calculated. Two trials discounted any increases in mf density in individuals at follow-up by setting any density increase to zero.For mf prevalence over two weeks to 12 months, albendazole alone or added to another microfilaricidal drug makes little or no difference (RR 0.95, 95% CI 0.85 to 1.07; 5027 participants, 12 trials, high-certainty evidence). For mf density there is no trend, with some trials reporting a greater reduction in mf density with albendazole and others a greater reduction with the control group. For mf density up to six months and at 12 months, we do not know if albendazole has an effect (one to six months: 1216 participants, 10 trials, very low-certainty evidence; at 12 months: 1052 participants, 9 trials, very low-certainty evidence).For antigenaemia prevalence between six to 12 months, albendazole alone or added to another microfilaricidal drug makes little or no difference (RR 1.04, 95% CI 0.97 to 1.12; 3774 participants, 7 trials, high-certainty evidence). For antigen density over six to 12 months, the trend shows little or no effect of albendazole; but we do not know if albendazole has an effect on antigen density (1374 participants, 5 trials, very low-certainty evidence). For adult worm prevalence detected by ultrasound at 12 months, albendazole added to a microfilaricidal drug may make little or no difference (RR 1.16, 95% CI 0.72 to 1.86; 165 participants, 3 trials, low-certainty evidence).For people reporting adverse events, albendazole makes little or no difference (RR 0.97, 95% CI 0.84 to 1.13; 2894 participants, 6 trials, high-certainty evidence).We also provide meta-analyses and GRADE tables by drug, as operationally this may be of interest: for albendazole versus placebo (4 trials, 1870 participants); for albendazole with DEC compared to DEC alone (8 trials, 3405 participants); and albendazole with ivermectin compared to ivermectin alone (4 trials, 3438 participants). AUTHORS' CONCLUSIONS There is good evidence that albendazole makes little difference to clearing microfilaraemia or adult filarial worms in the 12 months post-treatment. This finding is consistent in trials evaluating albendazole alone, or added to DEC or ivermectin. Trials reporting mf density included small numbers of participants, calculated density data variously, and gave inconsistent results.The review raises questions over whether albendazole has any important contribution to the elimination of lymphatic filariasis. To inform policy for areas with loiasis where only albendazole can be used, it may be worth conducting placebo-controlled trials of albendazole alone.
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Affiliation(s)
- Cara L Macfarlane
- Liverpool School of Tropical MedicineDepartment of Clinical SciencesPembroke PlaceLiverpoolUKL3 5QA
| | - Shyam S Budhathoki
- B P Koirala Institute of Health SciencesSchool of Public Health & Community MedicineGhopa 18DharanNepal
| | - Samuel Johnson
- Liverpool School of Tropical MedicineDepartment of Clinical SciencesPembroke PlaceLiverpoolUKL3 5QA
| | - Marty Richardson
- Liverpool School of Tropical MedicineDepartment of Clinical SciencesPembroke PlaceLiverpoolUKL3 5QA
| | - Paul Garner
- Liverpool School of Tropical MedicineDepartment of Clinical SciencesPembroke PlaceLiverpoolUKL3 5QA
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