Insights into the biology and insecticide susceptibility of the secondary malaria vector Anopheles parensis in an area with long-term use of insecticide-treated nets in northwestern Tanzania
Abstract Background The Anopheles funestus group includes at least 11 sibling species, with Anopheles funestus Giles being the most studied and significant malaria vector. Other species, like Anopheles parensis, are understudied despite their potential role in transmission. This article provides ins...
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2024-12-01
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| Series: | Parasites & Vectors |
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| Online Access: | https://doi.org/10.1186/s13071-024-06634-6 |
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| author | Salum Abdallah Mapua Ismail Hassan Nambunga Joel Ouma Odero Gustav Mkandawile John Paliga Masalu Najat Feruz Kahamba Emmanuel Elirehema Hape Nancy Stephen Matowo Frederic Tripet Fredros Oketch Okumu |
| author_facet | Salum Abdallah Mapua Ismail Hassan Nambunga Joel Ouma Odero Gustav Mkandawile John Paliga Masalu Najat Feruz Kahamba Emmanuel Elirehema Hape Nancy Stephen Matowo Frederic Tripet Fredros Oketch Okumu |
| author_sort | Salum Abdallah Mapua |
| collection | DOAJ |
| description | Abstract Background The Anopheles funestus group includes at least 11 sibling species, with Anopheles funestus Giles being the most studied and significant malaria vector. Other species, like Anopheles parensis, are understudied despite their potential role in transmission. This article provides insights into the biology and insecticide susceptibility of An. parensis, with observations of its densities in northwestern Tanzania. Methods Mosquitoes were collected in three villages in Misungwi district, northwestern Tanzania, using CDC light traps and battery-powered aspirators indoors and human-baited double net traps outdoors. Female Anopheles adults were morphologically sorted and identified by PCR, and a subset was tested by ELISA for vertebrate blood meal sources and Plasmodium sporozoite infections. Insecticide susceptibility was assessed using the WHO protocol (2nd edition, 2018). Unfed females were dissected to assess parity, gonotrophic status and insemination status, while blood-fed females were monitored for oviposition to estimate egg counts. The prevalence of An. parensis was generally < 24% across all sites, except in Ngaya village, where it unexpectedly constituted 84% of PCR-amplified An. funestus sensu lato. This species was present in both indoor and outdoor collections, yet the females exclusively fed on non-human vertebrates, with no human blood meals detected. Parity rates were approximately 49% for resting and 46% for host-seeking females, with slightly higher percentages of both parous and inseminated females in the dry season compared to the wet season. Most parous females had oviposited once or twice, with those in the dry season ovipositing significantly more eggs. The average wing length of female An. parensis was 2.93 mm, and there was no significant impact of body size on parity, fecundity or insemination. The An. parensis mosquitoes were fully susceptible to pyrethroids, carbamates, organophosphates and organochlorides. Results The prevalence of An. parensis was generally < 24% across all sites, except in Ngaya village, where it unexpectedly constituted 84% of PCR-amplified An. funestus sensu lato. This species was present in both indoor and outdoor collections, yet the females exclusively fed on non-human vertebrates, with no human blood meals detected. Parity rates were approximately 49% for resting and 46% for host-seeking females, with slightly higher percentages of both parous and inseminated females in the dry season compared to the wet season. Most parous females had oviposited once or twice, with those in the dry season ovipositing significantly more eggs. The average wing length of female An. parensis was 2.93 mm, and there was no significant impact of body size on parity, fecundity or insemination. The An. parensis mosquitoes were fully susceptible to pyrethroids, carbamates, organophosphates and organochlorides.. Conclusion This study offers insights into the behaviours and insecticide susceptibility of An. parensis. Primarily feeding on non-human hosts, An. parensis is less significant in malaria transmission than more anthropophilic vectors. Unlike the pyrethroid-resistant An. funestus sensu stricto, An. parensis remains fully susceptible to public health insecticides despite the use of insecticidal bed nets. These findings provide a foundation for future research and may inform control strategies targeting residual malaria transmission involving An. parensis. Graphical Abstract |
| format | Article |
| id | doaj-art-0e10ef63810240d0a011c99504ffa937 |
| institution | Kabale University |
| issn | 1756-3305 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | BMC |
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| series | Parasites & Vectors |
| spelling | doaj-art-0e10ef63810240d0a011c99504ffa9372025-01-05T12:10:06ZengBMCParasites & Vectors1756-33052024-12-011711910.1186/s13071-024-06634-6Insights into the biology and insecticide susceptibility of the secondary malaria vector Anopheles parensis in an area with long-term use of insecticide-treated nets in northwestern TanzaniaSalum Abdallah Mapua0Ismail Hassan Nambunga1Joel Ouma Odero2Gustav Mkandawile3John Paliga Masalu4Najat Feruz Kahamba5Emmanuel Elirehema Hape6Nancy Stephen Matowo7Frederic Tripet8Fredros Oketch Okumu9Environmental Health and Ecological Sciences Department, Ifakara Health InstituteEnvironmental Health and Ecological Sciences Department, Ifakara Health InstituteEnvironmental Health and Ecological Sciences Department, Ifakara Health InstituteEnvironmental Health and Ecological Sciences Department, Ifakara Health InstituteEnvironmental Health and Ecological Sciences Department, Ifakara Health InstituteEnvironmental Health and Ecological Sciences Department, Ifakara Health InstituteEnvironmental Health and Ecological Sciences Department, Ifakara Health InstituteDepartment of Disease Control, London School of Hygiene and Tropical MedicineSwiss Tropical and Public Health InstituteEnvironmental Health and Ecological Sciences Department, Ifakara Health InstituteAbstract Background The Anopheles funestus group includes at least 11 sibling species, with Anopheles funestus Giles being the most studied and significant malaria vector. Other species, like Anopheles parensis, are understudied despite their potential role in transmission. This article provides insights into the biology and insecticide susceptibility of An. parensis, with observations of its densities in northwestern Tanzania. Methods Mosquitoes were collected in three villages in Misungwi district, northwestern Tanzania, using CDC light traps and battery-powered aspirators indoors and human-baited double net traps outdoors. Female Anopheles adults were morphologically sorted and identified by PCR, and a subset was tested by ELISA for vertebrate blood meal sources and Plasmodium sporozoite infections. Insecticide susceptibility was assessed using the WHO protocol (2nd edition, 2018). Unfed females were dissected to assess parity, gonotrophic status and insemination status, while blood-fed females were monitored for oviposition to estimate egg counts. The prevalence of An. parensis was generally < 24% across all sites, except in Ngaya village, where it unexpectedly constituted 84% of PCR-amplified An. funestus sensu lato. This species was present in both indoor and outdoor collections, yet the females exclusively fed on non-human vertebrates, with no human blood meals detected. Parity rates were approximately 49% for resting and 46% for host-seeking females, with slightly higher percentages of both parous and inseminated females in the dry season compared to the wet season. Most parous females had oviposited once or twice, with those in the dry season ovipositing significantly more eggs. The average wing length of female An. parensis was 2.93 mm, and there was no significant impact of body size on parity, fecundity or insemination. The An. parensis mosquitoes were fully susceptible to pyrethroids, carbamates, organophosphates and organochlorides. Results The prevalence of An. parensis was generally < 24% across all sites, except in Ngaya village, where it unexpectedly constituted 84% of PCR-amplified An. funestus sensu lato. This species was present in both indoor and outdoor collections, yet the females exclusively fed on non-human vertebrates, with no human blood meals detected. Parity rates were approximately 49% for resting and 46% for host-seeking females, with slightly higher percentages of both parous and inseminated females in the dry season compared to the wet season. Most parous females had oviposited once or twice, with those in the dry season ovipositing significantly more eggs. The average wing length of female An. parensis was 2.93 mm, and there was no significant impact of body size on parity, fecundity or insemination. The An. parensis mosquitoes were fully susceptible to pyrethroids, carbamates, organophosphates and organochlorides.. Conclusion This study offers insights into the behaviours and insecticide susceptibility of An. parensis. Primarily feeding on non-human hosts, An. parensis is less significant in malaria transmission than more anthropophilic vectors. Unlike the pyrethroid-resistant An. funestus sensu stricto, An. parensis remains fully susceptible to public health insecticides despite the use of insecticidal bed nets. These findings provide a foundation for future research and may inform control strategies targeting residual malaria transmission involving An. parensis. Graphical Abstracthttps://doi.org/10.1186/s13071-024-06634-6Anopheles parensisPlasmodium sppMalariaTanzania |
| spellingShingle | Salum Abdallah Mapua Ismail Hassan Nambunga Joel Ouma Odero Gustav Mkandawile John Paliga Masalu Najat Feruz Kahamba Emmanuel Elirehema Hape Nancy Stephen Matowo Frederic Tripet Fredros Oketch Okumu Insights into the biology and insecticide susceptibility of the secondary malaria vector Anopheles parensis in an area with long-term use of insecticide-treated nets in northwestern Tanzania Parasites & Vectors Anopheles parensis Plasmodium spp Malaria Tanzania |
| title | Insights into the biology and insecticide susceptibility of the secondary malaria vector Anopheles parensis in an area with long-term use of insecticide-treated nets in northwestern Tanzania |
| title_full | Insights into the biology and insecticide susceptibility of the secondary malaria vector Anopheles parensis in an area with long-term use of insecticide-treated nets in northwestern Tanzania |
| title_fullStr | Insights into the biology and insecticide susceptibility of the secondary malaria vector Anopheles parensis in an area with long-term use of insecticide-treated nets in northwestern Tanzania |
| title_full_unstemmed | Insights into the biology and insecticide susceptibility of the secondary malaria vector Anopheles parensis in an area with long-term use of insecticide-treated nets in northwestern Tanzania |
| title_short | Insights into the biology and insecticide susceptibility of the secondary malaria vector Anopheles parensis in an area with long-term use of insecticide-treated nets in northwestern Tanzania |
| title_sort | insights into the biology and insecticide susceptibility of the secondary malaria vector anopheles parensis in an area with long term use of insecticide treated nets in northwestern tanzania |
| topic | Anopheles parensis Plasmodium spp Malaria Tanzania |
| url | https://doi.org/10.1186/s13071-024-06634-6 |
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