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Nie P, He C, Feng J. Range dynamics of Anopheles mosquitoes in Africa suggest a significant increase in the malaria transmission risk. Ecol Evol 2024; 14:e70059. [PMID: 39091337 PMCID: PMC11289791 DOI: 10.1002/ece3.70059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2024] [Revised: 06/07/2024] [Accepted: 07/10/2024] [Indexed: 08/04/2024] Open
Abstract
Despite a more than 100-year effort to combat malaria, it remains one of the most malignant infectious diseases globally, especially in Africa. Malaria is transmitted by several Anopheles mosquitoes. However, until now few studies have investigated future range dynamics of major An. mosquitoes in Africa through a unified scheme. Through a unified scheme, we developed 21 species distribution models to predict the range dynamics of 21 major An. species in Africa under future scenarios and also examined their overall range dynamic patterns mainly through suitability overlap index and range overlap index. Although future range dynamics varied substantially among the 21 An. species, we predicted large future range expansions for all 21 An. species, and increases in suitability overlap index were detected in more than 90% of the African continent for all future scenarios. Additionally, we predicted high range overlap index in West Africa, East Africa, South Sudan, Angola, and the Democratic Republic of the Congo under future scenarios. Although the relative impacts of land use, topography and climate variables on the range dynamics depended on species and spatial scale, climate played the strongest roles in the range dynamics of most species. Africa might face an increasing risk of malaria transmissions in the future, and better strategies are required to address this problem. Mitigating climate change and human disturbance of natural ecosystems might be essential to reduce the proliferation of An. species and the risk of malaria transmissions in Africa in the future. Our strategies against their impacts should be species-specific.
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Affiliation(s)
- Peixiao Nie
- College of Agriculture and Biological Science Dali University Dali China
- Cangshan Forest Ecosystem Observation and Research Station of Yunnan Province Dali University Dali China
| | - Chunyan He
- College of Agriculture and Biological Science Dali University Dali China
| | - Jianmeng Feng
- College of Agriculture and Biological Science Dali University Dali China
- Cangshan Forest Ecosystem Observation and Research Station of Yunnan Province Dali University Dali China
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Wangrawa DW, Odero JO, Baldini F, Okumu F, Badolo A. Distribution and insecticide resistance profile of the major malaria vector Anopheles funestus group across the African continent. MEDICAL AND VETERINARY ENTOMOLOGY 2024; 38:119-137. [PMID: 38303659 DOI: 10.1111/mve.12706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 01/10/2024] [Indexed: 02/03/2024]
Abstract
There has been significant progress in malaria control in the last 2 decades, with a decline in mortality and morbidity. However, these gains are jeopardised by insecticide resistance, which negatively impacts the core interventions, such as insecticide-treated nets (ITN) and indoor residual spraying (IRS). While most malaria control and research efforts are still focused on Anopheles gambiae complex mosquitoes, Anopheles funestus remains an important vector in many countries and, in some cases, contributes to most of the local transmission. As countries move towards malaria elimination, it is important to ensure that all dominant vector species, including An. funestus, an important vector in some countries, are targeted. The objective of this review is to compile and discuss information related to A. funestus populations' resistance to insecticides and the mechanisms involved across Africa, emphasising the sibling species and their resistance profiles in relation to malaria elimination goals. Data on insecticide resistance in An. funestus malaria vectors in Africa were extracted from published studies. Online bibliographic databases, including Google Scholar and PubMed, were used to search for relevant studies. Articles published between 2000 and May 2023 reporting resistance of An. funestus to insecticides and associated mechanisms were included. Those reporting only bionomics were excluded. Spatial variation in species distribution and resistance to insecticides was recorded from 174 articles that met the selection criteria. It was found that An. funestus was increasingly resistant to the four classes of insecticides recommended by the World Health Organisation for malaria vector control; however, this varied by country. Insecticide resistance appears to reduce the effectiveness of vector control methods, particularly IRS and ITN. Biochemical resistance due to detoxification enzymes (P450s and glutathione-S-transferases [GSTs]) in An. funestus was widely recorded. However, An. funestus in Africa remains susceptible to other insecticide classes, such as organophosphates and neonicotinoids. This review highlights the increasing insecticide resistance of An. funestus mosquitoes, which are important malaria vectors in Africa, posing a significant challenge to malaria control efforts. While An. funestus has shown resistance to the recommended insecticide classes, notably pyrethroids and, in some cases, organochlorides and carbamates, it remains susceptible to other classes of insecticides such as organophosphates and neonicotinoids, providing potential alternative options for vector control strategies. The study underscores the need for targeted interventions that consider the population structure and geographical distribution of An. funestus, including its sibling species and their insecticide resistance profiles, to effectively achieve malaria elimination goals.
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Affiliation(s)
- Dimitri W Wangrawa
- Laboratoire d'Entomologie Fondamentale et Appliquée, Université Joseph Ki-Zerbo, Ouagadougou, Burkina Faso
- Département des Sciences de la Vie et de la Terre, Université Norbert Zongo, Koudougou, Burkina Faso
| | - Joel O Odero
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- School of Biodiversity, One Health, and Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Francesco Baldini
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- School of Biodiversity, One Health, and Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Fredros Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Athanase Badolo
- Laboratoire d'Entomologie Fondamentale et Appliquée, Université Joseph Ki-Zerbo, Ouagadougou, Burkina Faso
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Ismail RBY, Bozorg-Omid F, Osei JHN, Pi-Bansa S, Frempong KK, Ofei MK, Boakye HA, Ansah-Owusu J, Akorful SCA, Tawiah-Mensah CNL, Abudu M, Asafu-Adjaye A, Appawu MA, Boakye DA, Vatandoost H, Sedaghat MM, Youssefi F, Hanafi-Bojd AA, Dadzie SK. Predicting the environmental suitability for Anopheles stephensi under the current conditions in Ghana. Sci Rep 2024; 14:1116. [PMID: 38212448 PMCID: PMC10784561 DOI: 10.1038/s41598-024-51780-7] [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: 08/27/2023] [Accepted: 01/09/2024] [Indexed: 01/13/2024] Open
Abstract
Vector-borne diseases emergence, particularly malaria, present a significant public health challenge worldwide. Anophelines are predominant malaria vectors, with varied distribution, and influenced by environment and climate. This study, in Ghana, modelled environmental suitability for Anopheles stephensi, a potential vector that may threaten advances in malaria and vector control. Understanding this vector's distribution and dynamics ensures effective malaria and vector control programmes implementation. We explored the MaxEnt ecological modelling method to forecast An. stephensi's potential hotspots and niches. We analysed environmental and climatic variables to predict spatial distribution and ecological niches of An. stephensi with a spatial resolution of approximately 5 km2. Analysing geospatial and species occurrence data, we identified optimal environmental conditions and important factors for its presence. The model's most important variables guided hotspot prediction across several ecological zones aside from urban and peri-urban regions. Considering the vector's complex bionomics, these areas provide varying and adaptable conditions for the vector to colonise and establish. This is shown by the AUC = 0.943 prediction accuracy of the model, which is considered excellent. Based on our predictions, this vector species would thrive in the Greater Accra, Ashanti Central, Upper East, Northern, and North East regions. Forecasting its environmental suitability by ecological niche modelling supports proactive surveillance and focused malaria management strategies. Public health officials can act to reduce the risk of malaria transmission by identifying areas where mosquitoes may breed, which will ultimately improve health outcomes and disease control.
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Affiliation(s)
- Rahmat Bint Yusif Ismail
- Department of Vector Biology and Control of Diseases, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Faramarz Bozorg-Omid
- Department of Vector Biology and Control of Diseases, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Joseph Harold Nyarko Osei
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Sellase Pi-Bansa
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Kwadwo Kyeremeh Frempong
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Mavis Koryo Ofei
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Helena Anokyewaa Boakye
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Jane Ansah-Owusu
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Sandra-Candys Adwirba Akorful
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | | | - Mufeez Abudu
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Andy Asafu-Adjaye
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Maxwell Alexander Appawu
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Daniel Adjei Boakye
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Hassan Vatandoost
- Department of Vector Biology and Control of Diseases, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Mehdi Sedaghat
- Department of Vector Biology and Control of Diseases, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Fahimeh Youssefi
- Department of Photogrammetry and Remote Sensing, K. N. Toosi University of Technology, Tehran, Iran
| | - Ahmad Ali Hanafi-Bojd
- Department of Vector Biology and Control of Diseases, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
- Zoonoses Research Center, Tehran University of Medical Sciences, Tehran, Iran.
| | - Samuel Kweku Dadzie
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana.
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Quaye IK, Aleksenko L, Paganotti GM, Peloewetse E, Haiyambo DH, Ntebela D, Oeuvray C, Greco B. Malaria Elimination in Africa: Rethinking Strategies for Plasmodium vivax and Lessons from Botswana. Trop Med Infect Dis 2023; 8:392. [PMID: 37624330 PMCID: PMC10458071 DOI: 10.3390/tropicalmed8080392] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 07/21/2023] [Accepted: 07/22/2023] [Indexed: 08/26/2023] Open
Abstract
The global malaria community has picked up the theme of malaria elimination in more than 90% of the world's population in the next decade. Recent reports of Plasmodium vivax (P. vivax) in sub-Saharan Africa, including in Duffy-negative individuals, threaten the efforts aimed at achieving elimination. This is not only in view of strategies that are tailored only to P. falciparum elimination but also due to currently revealed biological characteristics of P. vivax concerning the relapse patterns of hypnozoites and conservation of large biomasses in cryptic sites in the bone marrow and spleen. A typical scenario was observed in Botswana between 2008 and 2018, which palpably projects how P. vivax could endanger malaria elimination efforts where the two parasites co-exist. The need for the global malaria community, national malaria programs (NMPs), funding agencies and relevant stakeholders to engage in a forum to discuss and recommend clear pathways for elimination of malaria, including P. vivax, in sub-Saharan Africa is warranted.
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Affiliation(s)
- Isaac K. Quaye
- Pan African Vivax and Ovale Network, Faculty of Engineering Computer and Allied Sciences, Regent University College of Science and Technology, #1 Regent Ave, McCarthy Hill, Mendskrom, Dansoman, Accra P.O. Box DS1636, Ghana
| | - Larysa Aleksenko
- Department of Health Sciences, School of Public Health, College of Health, Medicine and Life Sciences, Brunel University, Kingston Lane, Uxbridge, Middlesex, London UB8 3PH, UK;
| | - Giacomo M. Paganotti
- Botswana-University of Pennsylvania Partnership, Riverwalk, Gaborone P.O. Box 45498, Botswana;
- Division of Infectious Diseases, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Elias Peloewetse
- Department of Biological Sciences, Faculty of Sciences, University of Botswana, Gaborone Private Bag 00704, Botswana;
| | - Daniel H. Haiyambo
- Department of Human, Biological and Translational Medical Sciences, Faculty of Health Sciences and Veterinary Medicine, University of Namibia School of Medicine, Hage Geingob Campus, Windhoek Private Bag 13301, Namibia;
| | - Davies Ntebela
- National Malaria Program, Ministry of Health, Gaborone Private Bag 0038, Botswana;
| | - Claude Oeuvray
- Global Health Institute of Merck, Terre Bonne Building Z0, Route de Crassier 1, Eysin, 1266 Geneva, Switzerland; (C.O.); (B.G.)
| | - Beatrice Greco
- Global Health Institute of Merck, Terre Bonne Building Z0, Route de Crassier 1, Eysin, 1266 Geneva, Switzerland; (C.O.); (B.G.)
| | - the PAVON Consortium
- PAVON, Regent University College of Science and Technology, #1 Regent Avenue, McCarthy Hiil, Mendskrom, Dansoman, Accra P.O. Box DS1636, Ghana
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Iga J, Ochaya S, Echodu R, Opiyo EA, Musiime AK, Nakamaanya A, Malinga GM. Sibling Species Composition and Susceptibility Status of Anopheles gambiae s.l. to Insecticides Used for Indoor Residual Spraying in Eastern Uganda. J Parasitol Res 2023; 2023:2225233. [PMID: 37469527 PMCID: PMC10352534 DOI: 10.1155/2023/2225233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 06/09/2023] [Accepted: 06/22/2023] [Indexed: 07/21/2023] Open
Abstract
Background Malaria remains one of the most critical disease causing morbidity and mortality in Uganda. Indoor residual spraying (IRS) and the use of insecticide-treated bed nets are currently the predominant malaria vector control interventions. However, the emergence and spread of insecticide resistance among malaria vectors threaten the continued effectiveness of these interventions to control the disease, particularly in high transmission areas. To inform decisions on vector control, the current study evaluated the Anopheles malaria vector species and their susceptibility levels to 0.1% bendiocarb and 0.25% pirimiphos-methyl insecticides used in IRS intervention program in Namutumba district, Eastern Uganda. Methods Anopheles larvae were collected between March and May 2017 from different breeding sites in the parishes of Nsinze and Nawaikona in Nsinze sub-county and reared to adults to assess the susceptibility status of populations in the study area. Mosquitoes were identified using morphological keys and species-specific polymerase chain reaction (PCR) assays. Susceptibility tests were conducted on 2- to 5-day-old non-blood-fed adult female Anopheles that emerged using insecticide-impregnated papers with 0.1% bendiocarb and 0.25% pirimiphos-methyl following standard World Health Organization (WHO) insecticide susceptibility bioassays. A Log-probit regression model was used to derive the knock-down rates for 50% and 95% of exposed mosquitoes. Results A total of 700 mosquito larvae were collected from different breeding sites. Morphological identification showed that 500 individuals that emerged belonged to Anopheles gambiae sensu lato (s.l.), the main malaria vector. The PCR results showed that the dominant sibling species under the A. gambiae complex was Anopheles arabiensis 99.5% (395/397). WHO bioassay tests revealed that the population of mosquitoes exhibited high levels of susceptibility (24-hour post-exposure mortality 98-100%) to both insecticides tested. The median knock-down time, KDT50, ranged from 6.6 to 81.4 minutes, while the KDT95 ranged from 21.6 to 118.9 minutes for 0.25% pirimiphos-methyl. The KDT50 for 0.1% bendiocarb ranged from 2.8 to 62.9 minutes, whereas the KDT95 ranged from 36.0 to 88.5 minutes. Conclusions These findings indicate that bendiocarb and pirimiphos-methyl are still effective against the major malaria vector, A. arabiensis in Nsinze sub-county, Namutumba district, Uganda and can be effectively used for IRS. The study has provided baseline information on the insecticide susceptibility status on malaria vectors in the study area. However, routine continuous monitoring program of insecticide susceptibility and malaria vector composition is required so as to guide future decisions on insecticide use for IRS intervention toward malaria elimination and to track future changes in vector population.
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Affiliation(s)
- Julius Iga
- Department of Biology, Faculty of Science, Gulu University, P.O. Box 166 Gulu, Uganda
| | - Stephen Ochaya
- Department of Immunology and Microbiology, Faculty of Medicine, Gulu University, P.O. Box 166 Gulu, Uganda
| | - Richard Echodu
- Department of Biology, Faculty of Science, Gulu University, P.O. Box 166 Gulu, Uganda
| | - Elizabeth A. Opiyo
- Department of Biology, Faculty of Science, Gulu University, P.O. Box 166 Gulu, Uganda
| | - Alex K. Musiime
- National Malaria Control Division, Ministry of Health, Uganda
| | | | - Geoffrey M. Malinga
- Department of Biology, Faculty of Science, Gulu University, P.O. Box 166 Gulu, Uganda
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Kouamé RM, Lynd A, Kouamé JK, Vavassori L, Abo K, Donnelly MJ, Edi C, Lucas E. Widespread occurrence of copy number variants and fixation of pyrethroid target site resistance in Anopheles gambiae ( s.l.) from southern Côte d'Ivoire. CURRENT RESEARCH IN PARASITOLOGY & VECTOR-BORNE DISEASES 2023; 3:100117. [PMID: 36970448 PMCID: PMC10031352 DOI: 10.1016/j.crpvbd.2023.100117] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 02/09/2023] [Accepted: 02/21/2023] [Indexed: 03/07/2023]
Abstract
Resistance to pyrethroid and organophosphate insecticides in the malaria vector Anopheles gambiae (s.l.) is conferred by a variety of genetic mutations, including single nucleotide polymorphisms (SNPs) and copy number variants (CNVs). Knowledge of the distribution of these mutations in mosquito populations is a prerequisite for establishing better strategies for their management. In this study, a total of 755 Anopheles gambiae (s.l.) from southern Côte d'Ivoire were exposed to deltamethrin or pirimiphos-methyl insecticides and were screened to assess the distribution of SNPs and CNVs known or believed to confer resistance to one or other of the insecticide classes. Most individuals from the An. gambiae (s.l.) complex were identified by molecular tests as Anopheles coluzzii. Survival to deltamethrin (from 94% to 97%) was higher than to pirimiphos-methyl (from 10% to 49%). In An. gambiae (s.s.), the SNP in the Voltage Gated Sodium Channel (Vgsc) at the 995F locus (Vgsc-995F) was fixed, while other target site mutations were rare or absent (Vgsc-402L: 0%; Vgsc-1570Y: 0%, Acetylcholinesterase Acel-280S: 14%). In An. coluzzii, Vgsc-995F was the target site SNP found at highest frequency (65%) followed by other target site mutations (Vgsc-402L: 36%; Vgsc-1570Y: 0.33%; Acel-280S: 45%). The Vgsc-995S SNP was not present. The presence of the Ace1-280S SNP was found to be significantly linked to the presence of the Ace1-CNV, Ace1_AgDup. Significant association was found between the presence of the Ace1_AgDup and pirimiphos-methyl resistance in An. gambiae (s.s.) but not in An. coluzzii. The deletion Ace1_Del97 was found in one specimen of An. gambiae (s.s.). Four CNVs in the Cyp6aa/Cyp6p gene cluster, which contains genes of known importance for resistance, were detected in An. coluzzii, the most frequent being Dup 7 (42%) and Dup 14 (26%). While none of these individual CNV alleles were significantly associated with resistance, copy number in the Cyp6aa gene region in general was associated with increased resistance to deltamethrin. Elevated expression of Cyp6p3 was nearly associated with deltamethrin resistance, although there was no association of resistance with copy number. Use of alternative insecticides and control methods to arrest resistance spread in An. coluzzii populations is merited.
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Affiliation(s)
- Ruth M.A. Kouamé
- Institut National Polytechnique Félix Houphouët Boigny, BP 1093, Yamoussoukro, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303 Abidjan 01, Côte d’Ivoire
| | - Amy Lynd
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Jackson K.I. Kouamé
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303 Abidjan 01, Côte d’Ivoire
- Université Nangui Abrogoua, 02 BP 801 Abidjan 02, Côte d’Ivoire
| | - Laura Vavassori
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303 Abidjan 01, Côte d’Ivoire
- Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Kouabénan Abo
- Institut National Polytechnique Félix Houphouët Boigny, BP 1093, Yamoussoukro, Côte d’Ivoire
| | - Martin J. Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Constant Edi
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303 Abidjan 01, Côte d’Ivoire
| | - Eric Lucas
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
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Salomé G, Riddin M, Braack L. Species Composition, Seasonal Abundance, and Biting Behavior of Malaria Vectors in Rural Conhane Village, Southern Mozambique. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:3597. [PMID: 36834293 PMCID: PMC9966379 DOI: 10.3390/ijerph20043597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/08/2023] [Accepted: 02/10/2023] [Indexed: 06/18/2023]
Abstract
Malaria vector surveillance provides important data to inform the effective planning of vector control interventions at a local level. The aim of this study was to determine the species diversity and abundance, biting activity, and Plasmodium infectivity of Anopheles mosquitoes from a rural village in southern Mozambique. Human landing catches were performed monthly between December 2020 and August 2021. All collected Anopheles were identified to the species level and tested for the presence of malaria parasites. Eight Anopheles species were identified among the 1802 collected anophelines. Anopheles gambiae sensu lato (s.l.) were the most abundant (51.9%) and were represented by Anopheles quadriannulatus and Anopheles arabiensis. Anopheles funestus s.l. represented 4.5%. The biting activity of An. arabiensis was more pronounced early in the evening and outdoors, whereas that of An. funestus sensu stricto (s.s.) was more intense late in the night, with no significant differences in location. One An. funestus s.s. and one An. arabiensis, both collected outdoors, were infected with Plasmodium falciparum. The overall entomologic inoculation rate was estimated at 0.015 infective bites per person per night. The significant outdoor and early evening biting activity of An. arabiensis and An. funestus found in this village may negatively impact the effectiveness of current vector control interventions. Additional vector control tools that can target these mosquitoes are needed.
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Affiliation(s)
- Graça Salomé
- UP Institute for Sustainable Malaria Control, School of Health Systems and Public Health, Faculty of Health Sciences, University of Pretoria, Pretoria 0028, South Africa
- Department of Physiological Sciences, Faculty of Medicine, Eduardo Mondlane University, 702 Salvador Allende Ave., Maputo P.O. Box 257, Mozambique
| | - Megan Riddin
- UP Institute for Sustainable Malaria Control, School of Health Systems and Public Health, Faculty of Health Sciences, University of Pretoria, Pretoria 0028, South Africa
| | - Leo Braack
- UP Institute for Sustainable Malaria Control, School of Health Systems and Public Health, Faculty of Health Sciences, University of Pretoria, Pretoria 0028, South Africa
- Malaria Consortium, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajavithi Rd, Ratchathewi, Bangkok 10400, Thailand
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Nkya TE, Fillinger U, Sangoro OP, Marubu R, Chanda E, Mutero CM. Six decades of malaria vector control in southern Africa: a review of the entomological evidence-base. Malar J 2022; 21:279. [PMID: 36184603 PMCID: PMC9526912 DOI: 10.1186/s12936-022-04292-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 09/05/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Countries in the southern Africa region have set targets for malaria elimination between 2020 and 2030. Malaria vector control is among the key strategies being implemented to achieve this goal. This paper critically reviews published entomological research over the past six decades in three frontline malaria elimination countries namely, Botswana Eswatini and Namibia, and three second-line malaria elimination countries including Mozambique, Zambia, and Zimbabwe. The objective of the review is to assess the current knowledge and highlight gaps that need further research attention to strengthen evidence-based decision-making toward malaria elimination. METHODS Publications were searched on the PubMed engine using search terms: "(malaria vector control OR vector control OR malaria vector*) AND (Botswana OR Swaziland OR Eswatini OR Zambia OR Zimbabwe OR Mozambique)". Opinions, perspectives, reports, commentaries, retrospective analysis on secondary data protocols, policy briefs, and reviews were excluded. RESULTS The search resulted in 718 publications with 145 eligible and included in this review for the six countries generated over six decades. The majority (139) were from three countries, namely Zambia (59) and Mozambique (48), and Zimbabwe (32) whilst scientific publications were relatively scanty from front-line malaria elimination countries, such as Namibia (2), Botswana (10) and Eswatini (4). Most of the research reported in the publications focused on vector bionomics generated mostly from Mozambique and Zambia, while information on insecticide resistance was mostly available from Mozambique. Extreme gaps were identified in reporting the impact of vector control interventions, both on vectors and disease outcomes. The literature is particularly scanty on important issues such as change of vector ecology over time and space, intervention costs, and uptake of control interventions as well as insecticide resistance. CONCLUSIONS The review reveals a dearth of information about malaria vectors and their control, most noticeable among the frontline elimination countries: Namibia, Eswatini and Botswana. It is of paramount importance that malaria vector research capacity and routine entomological monitoring and evaluation are strengthened to enhance decision-making, considering changing vector bionomics and insecticide resistance, among other determinants of malaria vector control.
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Affiliation(s)
- Theresia Estomih Nkya
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- University of Dar es Salaam, Mbeya College of Health and Allied Sciences, Mbeya, Tanzania
| | - Ulrike Fillinger
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | | | - Rose Marubu
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Emmanuel Chanda
- World Health Organization-Regional Office for Africa, Brazzaville, Republic of Congo
| | - Clifford Maina Mutero
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
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Makate N, Ramatlho P, Kgoroebutswe TK, Laycock K, Paganotti GM. Mosquito vector diversity and abundance in southern Botswana, in a global context of emerging pathogen transmission. J Public Health Afr 2022; 13:2029. [PMID: 36277950 PMCID: PMC9585606 DOI: 10.4081/jphia.2022.2029] [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: 09/09/2021] [Accepted: 04/15/2022] [Indexed: 11/23/2022] Open
Abstract
Background The continued spread of infectious diseases by mosquitoes remains a formidable obstacle to the well-being of the people all over the world. Arboviruses are spread from one vertebrate host to another by vectors through intricate transmission cycles that involve the virus, the vertebrate host, and the vector. It is essential to acquire a better understanding of the current abundance and distribution of major vectors in order to adequately prepare for the possibility of arbovirus outbreaks. This is because the abundance and distribution of these major vectors determines the human populations that are at risk for the diseases that they transmit. The effects of climate change on the amount of mosquitoes and their ability to survive the seasons have had a substantial impact on the spread of diseases that are transmitted by vectors in many different parts of Botswana. Methods The purpose was to collect mosquito samples in Gaborone and the neighboring areas in southern Botswana, including border stations. We collected different stages of the mosquito from each place, raised them to maturity, and then identified them. Both morphological and genetic studies were utilized in order to successfully identify the organism. The species of Culex mosquitoes accounted for 88.3% of the 5177 mosquitoes that were collected and identified, whereas the species of Aedes aegypti and Anopheles mosquitoes accounted for 11.5% and 0.2% respectively. Conclusions These findings give entomological baseline data that will aid in the study of vectorial patterns and the estimation of future arboviral hazards provided by mosquitoes. Additionally, these findings document the diversity and abundance of mosquito species.
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Buxton M, Buxton MP, Machekano H, Nyamukondiwa C, Wasserman RJ. A Survey of Potentially Pathogenic-Incriminated Arthropod Vectors of Health Concern in Botswana. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:10556. [PMID: 34639855 PMCID: PMC8508065 DOI: 10.3390/ijerph181910556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/20/2021] [Accepted: 09/27/2021] [Indexed: 11/17/2022]
Abstract
Arthropod vectors play a crucial role in the transmission of many debilitating infections, causing significant morbidity and mortality globally. Despite the economic significance of arthropods to public health, public knowledge on vector biology, ecology and taxonomic status remains anecdotal and largely unexplored. The present study surveyed knowledge gaps regarding the biology and ecology of arthropod vectors in communities of Botswana, across all districts. Results showed that communities are largely aware of individual arthropod vectors; however, their 'potential contribution' in disease transmission in humans, livestock and wildlife could not be fully attested. As such, their knowledge was largely limited with regards to some aspects of vector biology, ecology and control. Communities were strongly concerned about the burden of mosquitoes, cockroaches, flies and ticks, with the least concerns about fleas, bedbugs and lice, although the same communities did not know of specific diseases potentially vectored by these arthropods. Knowledge on arthropod vector control was mainly limited to synthetic chemical pesticides for most respondents, regardless of their location. The limited knowledge on potentially pathogen-incriminated arthropod vectors reported here has large implications for bridging knowledge gaps on the bio-ecology of these vectors countrywide. This is potentially useful in reducing the local burden of associated diseases and preventing the risk of emerging and re-emerging infectious diseases under global change.
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Affiliation(s)
- Mmabaledi Buxton
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, P/Bag 016, Palapye 10071, Botswana; (H.M.); (C.N.); (R.J.W.)
| | - Malebogo Portia Buxton
- Department of Sociology, University of Botswana, P/Bag UB 0022, Gaborone 00704, Botswana;
| | - Honest Machekano
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, P/Bag 016, Palapye 10071, Botswana; (H.M.); (C.N.); (R.J.W.)
| | - Casper Nyamukondiwa
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, P/Bag 016, Palapye 10071, Botswana; (H.M.); (C.N.); (R.J.W.)
| | - Ryan John Wasserman
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, P/Bag 016, Palapye 10071, Botswana; (H.M.); (C.N.); (R.J.W.)
- Department of Zoology and Entomology, Rhodes University, Makhanda 6140, South Africa
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11
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Buxton M, Nyamukondiwa C, Wasserman RJ, Othenin-Girard V, Pigeault R, Christe P, Glaizot O. Surveillance Studies Reveal Diverse and Potentially Pathogenic-Incriminated Vector Mosquito Species across Major Botswana Touristic Hotspots. INSECTS 2021; 12:913. [PMID: 34680682 PMCID: PMC8537495 DOI: 10.3390/insects12100913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 09/13/2021] [Accepted: 09/20/2021] [Indexed: 11/16/2022]
Abstract
Vector mosquitoes contribute significantly to the global burden of diseases in humans, livestock and wildlife. As such, the spatial distribution and abundance of mosquito species and their surveillance cannot be ignored. Here, we surveyed mosquito species across major tourism hotspots in semi-arid Botswana, including, for the first time, the Central Kalahari Game Reserve. Our results reported several mosquito species across seven genera, belonging to Aedes, Anopheles, Culex, Mansonia, Mimomyia, Coquillettidia and Uranotaenia. These results document a significant species inventory that may inform early warning vector-borne disease control systems and likely help manage the risk of emerging and re-emerging mosquito-borne infections.
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Affiliation(s)
- Mmabaledi Buxton
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, P/Bag 016, Palapye 10071, Botswana; (C.N.); (R.J.W.)
| | - Casper Nyamukondiwa
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, P/Bag 016, Palapye 10071, Botswana; (C.N.); (R.J.W.)
| | - Ryan J. Wasserman
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, P/Bag 016, Palapye 10071, Botswana; (C.N.); (R.J.W.)
- Department of Zoology and Entomology, Rhodes University, Makhanda 6140, South Africa
| | - Victor Othenin-Girard
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland; (V.O.-G.); (R.P.); (P.C.); (O.G.)
| | - Romain Pigeault
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland; (V.O.-G.); (R.P.); (P.C.); (O.G.)
- EBI Ecologie & Biologie des Interactions (UMR 7267), Université de Poitiers, 86000 Poitiers, France
| | - Philippe Christe
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland; (V.O.-G.); (R.P.); (P.C.); (O.G.)
| | - Olivier Glaizot
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland; (V.O.-G.); (R.P.); (P.C.); (O.G.)
- Museum of Zoology, 1014 Lausanne, Switzerland
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12
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Manake MG, Ramatlho P, Ntereke TD, Tawe L, Bango ZA, Quaye IK, Paganotti GM, Kasvosve I. Similar Ferroportin Q248H polymorphism prevalence in patients with Plasmodium falciparum malaria and control subjects in the low-endemic setting of Botswana. Clin Chim Acta 2021; 523:77-80. [PMID: 34534526 DOI: 10.1016/j.cca.2021.09.009] [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: 12/03/2020] [Revised: 09/10/2021] [Accepted: 09/11/2021] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Recent evidence suggests that ferroportin (FPN) Q248H may confer a survival advantage against malaria by reducing erythrocytic intracellular iron in Africans. We investigated if FPN Q248H mutation, that is prevalent in Batswana, is a factor in limiting the susceptibility to Plasmodium falciparum malaria. METHODS 264 archived dried blood spot samples (183 P. falciparum malaria cases and 81 controls, matched for geographical region and season for equal exposure) were genotyped. Human and P. falciparum DNA was extracted using Chelex-100 resin and P. falciparum molecular confirmation performed. Ferroportin Q248H mutation was identified by restriction fragment length polymorphism. The prevalence of the FPN Q248H mutation and allele frequency and the accompanying 95% confidence interval were calculated. A qPCR method was employed to estimate P. falciparum parasitaemia. Association between FPN and malaria susceptibility was tested using Pearson Chi-square test and Mood's median test was used to compare P. falciparum parasitaemias according to FPN Q248H mutation. RESULTS All samples were successfully genotyped. The FPN Q248H allele frequency was 0.08 (95% CI: 0.05-0.11) in cases and 0.08 (95% CI: 0.02-0.14) in controls, consistent with Hardy-Weinberg equilibrium. The prevalence of FPN Q248H phenotype was comparable in patients with P. falciparum malaria and in un-infected individuals, 16.4% (95% CI: 11.0-21.8) vs 14.8% (95% CI: 7.1-22.5), P = 0.746. In addition, no association of presence of FPN Q248H with reduced parasitaemia was recorded, P = 0.837. CONCLUSION In this small study, FPN Q248H polymorphism prevalence was comparable between patients with P. falciparum malaria and control subjects in the low-endemic setting of Botswana.
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Affiliation(s)
- Mokgadi G Manake
- School of Allied Health Professions, Faculty of Health Sciences, University of Botswana, Gaborone, Botswana
| | - Pleasure Ramatlho
- School of Allied Health Professions, Faculty of Health Sciences, University of Botswana, Gaborone, Botswana
| | - Tlhalefo D Ntereke
- School of Allied Health Professions, Faculty of Health Sciences, University of Botswana, Gaborone, Botswana
| | - Leabaneng Tawe
- School of Allied Health Professions, Faculty of Health Sciences, University of Botswana, Gaborone, Botswana; Botswana-University of Pennsylvania Partnership, Gaborone, Botswana
| | - Zackary A Bango
- Botswana-University of Pennsylvania Partnership, Gaborone, Botswana
| | - Isaac K Quaye
- Regent University College of Science and Technology, Accra, Ghana
| | - Giacomo M Paganotti
- Botswana-University of Pennsylvania Partnership, Gaborone, Botswana; Division of Infectious Diseases, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Biomedical Sciences, Faculty of Medicine, University of Botswana, Gaborone, Botswana
| | - Ishmael Kasvosve
- School of Allied Health Professions, Faculty of Health Sciences, University of Botswana, Gaborone, Botswana.
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13
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Buxton M, Wasserman RJ, Nyamukondiwa C. Disease Vector Relative Spatio-Temporal Abundances to Water Bodies and Thermal Fitness Across Malaria Endemic Semi-Arid Areas. JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:682-691. [PMID: 33107574 DOI: 10.1093/jme/tjaa221] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Indexed: 06/11/2023]
Abstract
The biophysical environment plays an important role in the spatio-temporal abundance and distribution of mosquitoes. This has implications for the spread of vectors and diseases they cause across diverse landscapes. Here, we assessed vector mosquito abundances in relation to large water bodies, from three malaria districts in a semi-arid environment. Furthermore, we explored thermal limits to activity of the dominant and most medically important malaria vector across malaria-endemic areas. Mosquitoes were trapped near permanent water bodies across different districts. Critical thermal limits (critical thermal-maxima and -minima) to activity of wild adults and 4th instar larvae Anopheles arabiensis (Diptera: Culicidae) were assessed. Our results showed that Anopheles spp. dominate mosquito communities across all three districts, but that their numbers were far greater in Okavango than in other regions. At the Okavango sites, the numbers of Anopheles spp. decreased with distance from main water source. Anopheles spp. sampled in this region comprised Anopheles gambiae (Giles,1902) and Anopheles funestus (Giles, 1900) species complexes, with the former dominating in numbers. Thermal activity assays showed An. arabiensis females had wider thermal tolerance windows than males while larval thermal activity limits differed significantly across space. These results confirm that the Okavango district should be prioritized for vector control measures. Moreover, intervention strategies should consider recommendations for proximity effects to large water bodies, given the differential risk associated with distance from water. The wider thermal window on female vectors has implications for possible future malaria transmission and diverse habitat utilization under changing environments.
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Affiliation(s)
- Mmabaledi Buxton
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Palapye, Botswana
| | - Ryan J Wasserman
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Palapye, Botswana
- Department of Zoology and Entomology, Rhodes University, Makhanda, South Africa
| | - Casper Nyamukondiwa
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Palapye, Botswana
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Buxton M, Wasserman RJ, Nyamukondiwa C. Spatial Anopheles arabiensis (Diptera: Culicidae) insecticide resistance patterns across malaria-endemic regions of Botswana. Malar J 2020; 19:415. [PMID: 33213466 PMCID: PMC7678117 DOI: 10.1186/s12936-020-03487-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 11/09/2020] [Indexed: 12/25/2022] Open
Abstract
Background Since the advent of the Green Revolution, pesticides have played an important role in the global management of invertebrate pests including vector mosquitoes. Despite optimal efficacy, insects often display insensitivity to synthetic insecticides owing to prolonged exposure that may select for resistance development. Such insecticide insensitivity may regress national and regional coordination in mosquito vector management and indeed malaria control. In Botswana, prolonged use of synthetic insecticides against malaria vectors have been practiced without monitoring of targeted mosquito species susceptibility status. Methods Here, susceptibility status of a malaria vector (Anopheles arabiensis), was assessed against World Health Organization-recommended insecticides, across three malaria endemic districts. Adult virgin female mosquitoes (2–5 days old) emerging from wild-collected larvae were exposed to standardized insecticide-impregnated papers with discriminating doses. Results The results showed resistance dynamics were variable in space, presumably as a result of spatial differences in insecticide use across malaria endemic districts and the types of insecticides used in the country. Overall, there was a reduced susceptibility of An. arabiensis for the pyrethroid lambda-cyhalothrin and for dichloro diphenyl trichloroethane [DDT], which have similar modes of action and have been used in the country for many years. The Okavango district exhibited the greatest reduction in susceptibility, followed by Ngamiland and then Bobirwa, reflective of national intervention strategy spraying intensities. Vector mosquitoes were, however, highly susceptible to carbamates and organophosphates irrespective of region. Conclusions These results provide important findings of vector susceptibility to insecticides recommended for vector control. The results highlight the need to implement insecticide application regimes that more effectively including regionally integrated resistance management strategies for effective malaria control and elimination.
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Affiliation(s)
- Mmabaledi Buxton
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Palapye, Botswana
| | - Ryan J Wasserman
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Palapye, Botswana.,Department of Zoology and Entomology, Rhodes University, Makhanda, 6140, South Africa
| | - Casper Nyamukondiwa
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, Palapye, Botswana.
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15
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Buxton M, Machekano H, Gotcha N, Nyamukondiwa C, Wasserman RJ. Are Vulnerable Communities Thoroughly Informed on Mosquito Bio-Ecology and Burden? INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E8196. [PMID: 33171954 PMCID: PMC7672552 DOI: 10.3390/ijerph17218196] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/24/2020] [Accepted: 09/25/2020] [Indexed: 11/25/2022]
Abstract
Mosquitoes account for a significant burden of morbidity and mortality globally. Despite evidence of (1) imminent anthropogenic climate and environmental changes, (2) vector-pathogen spatio-temporal dynamics and (3) emerging and re-emerging mosquito borne infections, public knowledge on mosquito bio-ecology remain scant. In particular, knowledge, attitude and practices (KAPs) on mosquitoes are often neglected despite otherwise expensive remedial efforts against consequent infections and other indirect effects associated with disease burden. To gather baseline KAPs that identify gaps for optimising vector-borne disease control, we surveyed communities across endemic and non-endemic malaria sub-districts (Botswana). The study revealed limited knowledge of mosquitoes and their infections uniformly across endemic and non-endemic areas. In addition, a significant proportion of respondents were concerned about mosquito burdens, although their level of personal, indoor and environmental protection practices varied significantly across sub-districts. Given the limited knowledge displayed by the communities, this study facilitates bridging KAP gaps to minimise disease burdens by strengthening public education. Furthermore, it provides a baseline for future studies in mosquito bio-ecology and desirable control practices across differential spheres of the rural-urban lifestyle, with implications for enhanced livelihoods as a consequence of improved public health.
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Affiliation(s)
- Mmabaledi Buxton
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology, P. Bag 16, Palapye, Botswana; (H.M.); (N.G.); (C.N.); (R.J.W.)
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16
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Bango ZA, Tawe L, Muthoga CW, Paganotti GM. Past and current biological factors affecting malaria in the low transmission setting of Botswana: A review. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2020; 85:104458. [PMID: 32668367 PMCID: PMC7354381 DOI: 10.1016/j.meegid.2020.104458] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 07/06/2020] [Accepted: 07/08/2020] [Indexed: 11/29/2022]
Abstract
Malaria continues to be one of the top infectious agents contributing to morbidity and mortality in sub-Saharan Africa. Annually, Botswana accounts only for a small proportion of cases (<<1%). Despite significantly reduced incidence rate, the country still experiences sporadic outbreaks that hamper the goal of malaria elimination. This review evaluated previous and current biological factors that impact malaria in Botswana, specifically focussing on the vectors, the parasite and the host. This was accomplished via a literature review evaluating these variables in Botswana. Current literature suggests that Anopheles arabiensis is the main malaria vector in the country. Several other potential vectors have been found widely distributed throughout Botswana in high numbers, yet remain largely unstudied with regards to their contribution to the country's malaria burden. We also report the most up to date list of all Anopheles species that have been found in Botswana. Plasmodium falciparum is responsible for the vast majority of symptomatic malaria in the country and some drug resistance markers have been documented for this species. Plasmodium vivax has been reported in asymptomatic subjects, even though a large proportion of the Botswana population appears to be Duffy antigen negative. Very little is known about the true distribution of P. vivax and no point of care testing infrastructure for this species exists in Botswana, making it difficult to tailor treatment to address possible recrudescence or relapse. Due to a genetically diverse population with a substantial Khoisan contribution into the Bantu genetic background, several phenotypes that potentially impact prevalence and severity of malaria exist within the country. These include sickle cell trait, Glucose-6-Phosphate Dehydrogenase deficiency, and Duffy negativity. This review highlights the information that currently exists on malaria in Botswana. It also postulates that a comprehensive understanding of these aforementioned biological factors may help to explain malaria persistence in Botswana.
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Affiliation(s)
| | - Leabaneng Tawe
- Botswana-University of Pennsylvania Partnership, Gaborone, Botswana; Department of Medical Laboratory Sciences, Faculty of Health Sciences, University of Botswana, Gaborone, Botswana
| | | | - Giacomo Maria Paganotti
- Botswana-University of Pennsylvania Partnership, Gaborone, Botswana; Division of Infectious Diseases, Perelman School of Medicine, University of Pennsylvania, PA, USA; Department of Biomedical Sciences, University of Botswana, Gaborone, Botswana.
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Vector control for malaria elimination in Botswana: progress, gaps and opportunities. Malar J 2020; 19:301. [PMID: 32843037 PMCID: PMC7449088 DOI: 10.1186/s12936-020-03375-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 08/13/2020] [Indexed: 12/29/2022] Open
Abstract
Botswana has in the recent past 10 years made tremendous progress in the control of malaria and this informed re-orientation from malaria control to malaria elimination by the year 2020. This progress is attributed to improved case management, and scale-up of key vector control interventions; indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs). However, insecticide resistance, outdoor biting and resting, and predisposing human behaviour, such as staying outdoors or sleeping outdoors without the use of protective measures, pose a challenge to the realization of the full impact of LLINs and IRS. This, together with the paucity of entomological data, inadequate resources and weak community participation for vector control programme implementation delayed attainment of Botswana’s goal of malaria elimination. Also, the Botswana National Malaria Programme (NMP) experiences the lack of intersectoral collaborations and operational research for evidence-based decision making. This case study focuses on the vector control aspect of malaria elimination by identifying challenges and explores opportunities that could be taken advantage of to benefit the NMP to optimize and augment the current vector control interventions to achieve malaria elimination by the year 2030 as per the Global Technical Strategy for Malaria 2016–2030 targets. The authors emphasize the need for timely and quality entomological surveillance, operational research and integrated vector management.
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18
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Distribution of Anopheles mosquito species, their vectorial role and profiling of knock-down resistance mutations in Botswana. Parasitol Res 2020; 119:1201-1208. [DOI: 10.1007/s00436-020-06614-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 01/22/2020] [Indexed: 01/21/2023]
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Cornel AJ, Lee Y, Almeida APG, Johnson T, Mouatcho J, Venter M, de Jager C, Braack L. Mosquito community composition in South Africa and some neighboring countries. Parasit Vectors 2018; 11:331. [PMID: 29859109 PMCID: PMC5984792 DOI: 10.1186/s13071-018-2824-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 03/28/2018] [Indexed: 11/25/2022] Open
Abstract
Background A century of studies have described particular aspects of relatively few mosquito species in southern Africa, mostly those species involved with disease transmission, specifically malaria and arboviruses. Patterns of community composition such as mosquito abundance and species diversity are often useful measures for medical entomologists to guide broader insights and projections regarding disease dynamics and potential introduction, spread or maintenance of globally spreading pathogens. However, little research has addressed these indicators in southern Africa. Results We collected 7882 mosquitoes from net and light traps at 11 localities comprising 66 species in 8 genera. We collected an additional 8 species using supplementary collection techniques such as larval sampling, sweep-netting and indoor pyrethrum knockdown catches. Highest diversity and species richness was found in the Okavango Delta of Botswana and in South Africa’s Kruger National Park, while the lowest diversity and abundances were in the extreme southern tip of South Africa and in semi-desert Kalahari close to the South Africa border with Botswana. Species composition was more similar between proximal localities than distant ones (Linear model P-value = 0.005). Multiple arbovirus vector species were detected in all localities we surveyed (proportion of vector mosquito numbers were > 0.5 in all locations except Shingwedzi). Their proportions were highest (> 90%) in Vilankulo and Kogelberg. Conclusions Multiple known arbovirus vector species were found in all study sites, whereas anopheline human malaria vector species in only some sites. The combination of net traps and light traps effectively sampled mosquito species attracted to carbon-dioxide or light, accounting for 89% of the 74 species collected. The 11% remaining species were collected using supplementary collection techniques mentioned above. The diversity of species weas highest in savanna type habitats, whereas low diversities were found in the drier Kalahari sands regions and the southern Cape fynbos regions. Electronic supplementary material The online version of this article (10.1186/s13071-018-2824-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anthony J Cornel
- Department of Entomology & Nematology, University of California, Davis, USA. .,UP Institute for Sustainable Malaria Control & MRC Collaborating Centre for Malaria Research, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa.
| | - Yoosook Lee
- Department of Entomology & Nematology, University of California, Davis, USA
| | - António Paulo Gouveia Almeida
- Global Health and Tropical Medicine, GHTM, Institute for Hygiene and Tropical Medicine, IHMT, Universidade Nova de Lisboa, UNL, Lisbon, Portugal.,Centre for Viral Zoonoses, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Todd Johnson
- Centre for Viral Zoonoses, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Joel Mouatcho
- UP Institute for Sustainable Malaria Control & MRC Collaborating Centre for Malaria Research, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Marietjie Venter
- Centre for Viral Zoonoses, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Christiaan de Jager
- UP Institute for Sustainable Malaria Control & MRC Collaborating Centre for Malaria Research, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Leo Braack
- UP Institute for Sustainable Malaria Control & MRC Collaborating Centre for Malaria Research, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
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Obopile M, Segoea G, Waniwa K, Ntebela DS, Moakofhi K, Motlaleng M, Mosweunyane T, Edwards JK, Namboze J, Butt W, Manzi M, Takarinda KC, Owiti P. Did microbial larviciding contribute to a reduction in malaria cases in eastern Botswana in 2012-2013? Public Health Action 2018; 8:S50-S54. [PMID: 29713595 DOI: 10.5588/pha.17.0012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 09/17/2017] [Indexed: 11/10/2022] Open
Abstract
Setting: Larviciding has potential as a component of integrated vector management for the reduction of malaria transmission in Botswana by complementing long-lasting insecticide nets and indoor residual sprays. Objective: To evaluate the susceptibility of local Anopheles to commonly used larvicides. Design: This field test of the efficacy of Bacillus thuringiensis subsp. israliensis vs. Anopheles was performed by measuring larval density before treatment and 24 h and 48 h after treatment in seven sites of Bobirwa district, eastern Botswana, in 2012 and 2013. Vector density and malaria cases were compared between Bobirwa and Ngami (northwestern Botswana), with no larviciding in the control arm. Results: Larviciding reduced larval density by 95% in Bobirwa in 2012, with two cases of malaria, while in 2013 larval density reduction was 81%, with 11 cases. Adult mosquito density was zero for both years in Robelela village (Bobirwa), compared to respectively four and 26 adult mosquitoes per room in Shorobe village (Ngami) in 2012 and 2013. There were no cases of malaria in Robelela in either year, but in Shorobe there were 20 and 70 cases, respectively, in 2012 and 2013. Conclusion: Larviciding can reduce the larval density of mosquitoes and reduce malaria transmission in Botswana. Large-scale, targeted implementation of larviciding in districts at high risk for malaria is recommended.
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Affiliation(s)
- M Obopile
- Botswana University of Agriculture and Natural Resources, Gaborone, Botswana
| | - G Segoea
- National Malaria Programme, Botswana Ministry of Health, Gaborone, Botswana
| | - K Waniwa
- National Malaria Programme, Botswana Ministry of Health, Gaborone, Botswana
| | - D S Ntebela
- National Malaria Programme, Botswana Ministry of Health, Gaborone, Botswana
| | - K Moakofhi
- World Health Organization (WHO) Country Office for Botswana, Gaborone, Botswana
| | - M Motlaleng
- National Malaria Programme, Botswana Ministry of Health, Gaborone, Botswana
| | - T Mosweunyane
- National Malaria Programme, Botswana Ministry of Health, Gaborone, Botswana
| | | | - J Namboze
- Inter-Country Support Team, WHO, Harare, Zimbabwe
| | - W Butt
- Inter-Country Support Team, WHO, Harare, Zimbabwe
| | - M Manzi
- Médecins Sans Frontières, Brussels, Belgium
| | - K C Takarinda
- International Union Against Tuberculosis and Lung Disease, Paris, France
| | - P Owiti
- Academic Model Providing Access to Healthcare (AMPATH), Eldoret, Kenya
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Moakofhi K, Edwards JK, Motlaleng M, Namboze J, Butt W, Obopile M, Mosweunyane T, Manzi M, Takarinda KC, Owiti P. Advances in malaria elimination in Botswana: a dramatic shift to parasitological diagnosis, 2008-2014. Public Health Action 2018; 8:S34-S38. [PMID: 29713592 DOI: 10.5588/pha.17.0017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 08/22/2017] [Indexed: 11/10/2022] Open
Abstract
Background: Malaria elimination requires infection detection using quality assured diagnostics and appropriate treatment regimens. Although Botswana is moving towards malaria elimination, reports of unconfirmed cases may jeopardise this effort. This study aimed to determine the proportion of cases treated for malaria that were confirmed by rapid diagnostic testing (RDT) and/or microscopy. Methods: This was a retrospective descriptive study using routine national data from the integrated disease surveillance and case-based surveillance systems from 2008 to 2014. The data were categorised into clinical and confirmed cases each year. An analysis of the data on cases registered in three districts that reported approximately 70% of all malaria cases was performed, stratified by year, type of reporting health facilities and diagnostic method. Results: During 2008-2014, 50 487 cases of malaria were reported in Botswana, and the proportion of RDT and/or blood microscopy confirmed cases improved from 6% in 2008 to 89% in 2013. The total number of malaria cases decreased by 97% in the same period, then increased by 41% in 2013. Conclusion: This study shows that malaria diagnostic tests dramatically improved malaria diagnosis and consequently reduced the malaria burden in Botswana. The study identified a need to build capacity on microscopy for species identification, parasite quantification and guiding treatment choices.
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Affiliation(s)
- K Moakofhi
- World Health Organization (WHO) Botswana Country Office, Gaborone, Botswana
| | | | - M Motlaleng
- National Malaria Programme, Botswana Ministry of Health, Gaborone, Botswana
| | - J Namboze
- Inter-Country Support Team, WHO, Harare, Zimbabwe
| | - W Butt
- Inter-Country Support Team, WHO, Harare, Zimbabwe
| | - M Obopile
- Botswana University of Agriculture and Natural Resources, Gaborone, Botswana
| | - T Mosweunyane
- National Malaria Programme, Botswana Ministry of Health, Gaborone, Botswana
| | - M Manzi
- Médecins Sans Frontières, Brussels, Belgium
| | - K C Takarinda
- International Union Against Tuberculosis and Lung Disease, Paris, France
| | - P Owiti
- Academic Model Providing Access to Healthcare (AMPATH), Eldoret, Kenya
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