Estimates of the population size and dispersal range of Anopheles arabiensis in Northern KwaZulu-Natal, South Africa: implications for a planned pilot programme to release sterile male mosquitoes
Abstract Background Anopheles arabiensis is a major malaria vector, recently implicated as contributing to ongoing residual malaria transmission in South Africa, which feeds and rests both indoors and outdoors. This species is, therefore, not effectively targeted using core malaria vector control in...
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| Format: | Article |
| Language: | English |
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BMC
2021-04-01
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| Series: | Parasites & Vectors |
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| Online Access: | https://doi.org/10.1186/s13071-021-04674-w |
| _version_ | 1818459982660632576 |
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| author | Maria L. Kaiser Oliver R. Wood David Damiens Basil D. Brooke Lizette L. Koekemoer Givemore Munhenga |
| author_facet | Maria L. Kaiser Oliver R. Wood David Damiens Basil D. Brooke Lizette L. Koekemoer Givemore Munhenga |
| author_sort | Maria L. Kaiser |
| collection | DOAJ |
| description | Abstract Background Anopheles arabiensis is a major malaria vector, recently implicated as contributing to ongoing residual malaria transmission in South Africa, which feeds and rests both indoors and outdoors. This species is, therefore, not effectively targeted using core malaria vector control interventions alone. Additionally, increasing resistance to available insecticides necessitates investigations into complementary non-insecticide-based vector control methods for outdoor-resting mosquitoes. The feasibility of the sterile insect technique (SIT) as a complementary vector control intervention is being investigated in South Africa. Successful implementation of an SIT programme largely depends on inundating a target insect population with sterilized laboratory-bred males. Therefore, knowledge of the native population size and dispersal ability of released sterile laboratory-reared males is critical. In this study, we estimated the male An. arabiensis population size and the dispersal of released males in an area targeted for a pilot sterile male release programme. Methods Three separate releases were performed within a 2-year period. Approximately 5000–15,000 laboratory-reared male An. arabiensis (KWAG) were produced and marked for mark–release–recapture experiments. To recapture released mosquitoes, cloth tubes were deployed in widening concentric circles. The average dispersal distance of released males was calculated and the wild male An. arabiensis population size was estimated using two Lincoln index formulae. The natural population was sampled concurrently and Anopheles species diversity examined. Results The Anopheles gambiae complex and An. funestus group species made up the majority of wild collections along with other anophelines. The An. arabiensis population size was estimated to be between 550 and 9500 males per hectare depending on time of year, weather conditions and method used. Average dispersal distance of marked males ranged from 58 to 86 m. Marked males were found in swarms with wild males, indicating that laboratory-reared males are able to locate and participate in mating swarms. Conclusions It was logistically feasible to conduct mark–release–recapture studies at the current scale. The population size estimates obtained may provide a guideline for the initial number of males to use for a pending SIT pilot trial. It is promising for future SIT trials that laboratory-reared marked males participated in natural swarms, appearing at the right place at the right time. |
| first_indexed | 2024-12-14T23:23:00Z |
| format | Article |
| id | doaj.art-575f46e257d647d6a20e80bc5ce3307a |
| institution | Directory Open Access Journal |
| issn | 1756-3305 |
| language | English |
| last_indexed | 2024-12-14T23:23:00Z |
| publishDate | 2021-04-01 |
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| series | Parasites & Vectors |
| spelling | doaj.art-575f46e257d647d6a20e80bc5ce3307a2022-12-21T22:43:53ZengBMCParasites & Vectors1756-33052021-04-0114111810.1186/s13071-021-04674-wEstimates of the population size and dispersal range of Anopheles arabiensis in Northern KwaZulu-Natal, South Africa: implications for a planned pilot programme to release sterile male mosquitoesMaria L. Kaiser0Oliver R. Wood1David Damiens2Basil D. Brooke3Lizette L. Koekemoer4Givemore Munhenga5Centre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory ServiceCentre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory ServiceUMR IRD 224, Maladies Infectieuses et Vecteurs-Ecologie-Génétique, Evolution et Contrôle (MIVEGEC), Institut de Recherche Pour Le Développement (IRD) CNRS 5290–Université de MontpellierCentre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory ServiceCentre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory ServiceCentre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory ServiceAbstract Background Anopheles arabiensis is a major malaria vector, recently implicated as contributing to ongoing residual malaria transmission in South Africa, which feeds and rests both indoors and outdoors. This species is, therefore, not effectively targeted using core malaria vector control interventions alone. Additionally, increasing resistance to available insecticides necessitates investigations into complementary non-insecticide-based vector control methods for outdoor-resting mosquitoes. The feasibility of the sterile insect technique (SIT) as a complementary vector control intervention is being investigated in South Africa. Successful implementation of an SIT programme largely depends on inundating a target insect population with sterilized laboratory-bred males. Therefore, knowledge of the native population size and dispersal ability of released sterile laboratory-reared males is critical. In this study, we estimated the male An. arabiensis population size and the dispersal of released males in an area targeted for a pilot sterile male release programme. Methods Three separate releases were performed within a 2-year period. Approximately 5000–15,000 laboratory-reared male An. arabiensis (KWAG) were produced and marked for mark–release–recapture experiments. To recapture released mosquitoes, cloth tubes were deployed in widening concentric circles. The average dispersal distance of released males was calculated and the wild male An. arabiensis population size was estimated using two Lincoln index formulae. The natural population was sampled concurrently and Anopheles species diversity examined. Results The Anopheles gambiae complex and An. funestus group species made up the majority of wild collections along with other anophelines. The An. arabiensis population size was estimated to be between 550 and 9500 males per hectare depending on time of year, weather conditions and method used. Average dispersal distance of marked males ranged from 58 to 86 m. Marked males were found in swarms with wild males, indicating that laboratory-reared males are able to locate and participate in mating swarms. Conclusions It was logistically feasible to conduct mark–release–recapture studies at the current scale. The population size estimates obtained may provide a guideline for the initial number of males to use for a pending SIT pilot trial. It is promising for future SIT trials that laboratory-reared marked males participated in natural swarms, appearing at the right place at the right time.https://doi.org/10.1186/s13071-021-04674-wMalaria vector controlMalaria eliminationMale mosquitoesPopulation sizeOver-flooding ratioSterile insect technique |
| spellingShingle | Maria L. Kaiser Oliver R. Wood David Damiens Basil D. Brooke Lizette L. Koekemoer Givemore Munhenga Estimates of the population size and dispersal range of Anopheles arabiensis in Northern KwaZulu-Natal, South Africa: implications for a planned pilot programme to release sterile male mosquitoes Parasites & Vectors Malaria vector control Malaria elimination Male mosquitoes Population size Over-flooding ratio Sterile insect technique |
| title | Estimates of the population size and dispersal range of Anopheles arabiensis in Northern KwaZulu-Natal, South Africa: implications for a planned pilot programme to release sterile male mosquitoes |
| title_full | Estimates of the population size and dispersal range of Anopheles arabiensis in Northern KwaZulu-Natal, South Africa: implications for a planned pilot programme to release sterile male mosquitoes |
| title_fullStr | Estimates of the population size and dispersal range of Anopheles arabiensis in Northern KwaZulu-Natal, South Africa: implications for a planned pilot programme to release sterile male mosquitoes |
| title_full_unstemmed | Estimates of the population size and dispersal range of Anopheles arabiensis in Northern KwaZulu-Natal, South Africa: implications for a planned pilot programme to release sterile male mosquitoes |
| title_short | Estimates of the population size and dispersal range of Anopheles arabiensis in Northern KwaZulu-Natal, South Africa: implications for a planned pilot programme to release sterile male mosquitoes |
| title_sort | estimates of the population size and dispersal range of anopheles arabiensis in northern kwazulu natal south africa implications for a planned pilot programme to release sterile male mosquitoes |
| topic | Malaria vector control Malaria elimination Male mosquitoes Population size Over-flooding ratio Sterile insect technique |
| url | https://doi.org/10.1186/s13071-021-04674-w |
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