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Mwalimu CD, Kiware S, Nshama R, Derua Y, Machafuko P, Gitanya P, Mwafongo W, Bernard J, Emidi B, Mwingira V, Malima R, Githu V, Masanja B, Mlacha Y, Tungu P, Kabula B, Sambu E, Batengana B, Matowo J, Govella N, Chaki P, Lazaro S, Serbantez N, Kitau J, Magesa SM, Kisinza WN. Dynamics of malaria vector composition and Plasmodium falciparum infection in mainland Tanzania: 2017-2021 data from the national malaria vector entomological surveillance. Malar J 2024; 23:29. [PMID: 38243220 PMCID: PMC10797900 DOI: 10.1186/s12936-024-04849-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 01/10/2024] [Indexed: 01/21/2024] Open
Abstract
BACKGROUND In 2015, Tanzania National Malaria Control Programme (NMCP) established a longitudinal malaria vector entomological surveillance (MVES). The MVES is aimed at a periodical assessment of malaria vector composition and abundance, feeding and resting behaviours, and Plasmodium falciparum infection in different malaria epidemiological strata to guide the NMCP on the deployment of appropriate malaria vector interventions. This work details the dynamics of malaria vector composition and transmission in different malaria epidemiological strata. METHODS The MVES was conducted from 32 sentinel district councils across the country. Mosquitoes were collected by the trained community members and supervised by the NMCP and research institutions. Three consecutive night catches (indoor collection with CDC light trap and indoor/outdoor collection using bucket traps) were conducted monthly in three different households selected randomly from two to three wards within each district council. Collected mosquitoes were sorted and morphologically identified in the field. Thereafter, the samples were sent to the laboratory for molecular characterization using qPCR for species identification and detection of P. falciparum infections (sporozoites). ELISA technique was deployed for blood meal analysis from samples of blood-fed mosquitoes to determine the blood meal indices (BMI). RESULTS A total of 63,226 mosquitoes were collected in 32 district councils from January 2017 to December 2021. Out of which, 39,279 (62%), 20,983 (33%) and 2964 (5%) were morphologically identified as Anopheles gambiae sensu lato (s.l.), Anopheles funestus s.l., and as other Anopheles species, respectively. Out of 28,795 laboratory amplified mosquitoes, 13,645 (47%) were confirmed to be Anopheles arabiensis, 9904 (34%) as An. funestus sensu stricto (s.s.), and 5193 (19%) as An. gambiae s.s. The combined average entomological inoculation rates (EIR) were 0.46 (95% CI 0.028-0.928) for An. gambiae s.s., 0.836 (95% CI 0.138-1.559) for An. arabiensis, and 0.58 (95% CI 0.165-0.971) for An. funestus s.s. with variations across different malaria transmission strata. Anopheles funestus s.s. and An. arabiensis were predominant in the Lake and South-Eastern zones, respectively, mostly in high malaria transmission areas. Monthly mosquito densities displayed seasonal patterns, with two peaks following the rainy seasons, varying slightly across species and district councils. CONCLUSION Anopheles arabiensis remains the predominant vector species followed by An. funestus s.s. in the country. Therefore, strengthening integrated vector management including larval source management is recommended to address outdoor transmission by An. arabiensis to interrupt transmission particularly where EIR is greater than the required elimination threshold of less than one (< 1) to substantially reduce the prevalence of malaria infection.
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Affiliation(s)
- Charles D Mwalimu
- National Malaria Control Programme (NMCP), Dodoma, United Republic of Tanzania
| | - Samson Kiware
- Ifakara Health Institute (IHI), Dar es Salaam, Tanzania.
- Pan African Mosquito Control Association (PAMCA), Dar es Salaam, Tanzania.
| | - Rosemary Nshama
- National Malaria Control Programme (NMCP), Dodoma, United Republic of Tanzania
| | - Yahya Derua
- National Institute for Medical Research (NIMR), Amani Centre, Muheza, Tanzania
| | - Pendael Machafuko
- National Institute for Medical Research (NIMR), Amani Centre, Muheza, Tanzania
| | - Peter Gitanya
- National Malaria Control Programme (NMCP), Dodoma, United Republic of Tanzania
| | - Winfred Mwafongo
- National Malaria Control Programme (NMCP), Dodoma, United Republic of Tanzania
| | - Jubilate Bernard
- National Malaria Control Programme (NMCP), Dodoma, United Republic of Tanzania
| | - Basiliana Emidi
- National Institute for Medical Research (NIMR), Mwanza, Tanzania
| | - Victor Mwingira
- National Institute for Medical Research (NIMR), Amani Centre, Muheza, Tanzania
| | - Robert Malima
- National Institute for Medical Research (NIMR), Amani Centre, Muheza, Tanzania
- University of Dar es Salaam, Mbeya College of Health and Allied Sciences, Mbeya, Tanzania
| | | | - Brian Masanja
- Ifakara Health Institute (IHI), Dar es Salaam, Tanzania
| | - Yeromin Mlacha
- Ifakara Health Institute (IHI), Dar es Salaam, Tanzania
- Pan African Mosquito Control Association (PAMCA), Dar es Salaam, Tanzania
| | - Patrick Tungu
- National Institute for Medical Research (NIMR), Amani Centre, Muheza, Tanzania
| | - Bilali Kabula
- National Institute for Medical Research (NIMR), Amani Centre, Muheza, Tanzania
| | - Edward Sambu
- National Institute for Medical Research (NIMR), Amani Centre, Muheza, Tanzania
| | - Bernard Batengana
- National Institute for Medical Research (NIMR), Amani Centre, Muheza, Tanzania
| | - Johnson Matowo
- Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Nicodem Govella
- Ifakara Health Institute (IHI), Dar es Salaam, Tanzania
- Population Services International (PSI), Dar es Salaam, Tanzania
| | - Prosper Chaki
- Ifakara Health Institute (IHI), Dar es Salaam, Tanzania
- Pan African Mosquito Control Association (PAMCA), Dar es Salaam, Tanzania
| | - Samwel Lazaro
- National Malaria Control Programme (NMCP), Dodoma, United Republic of Tanzania
| | - Naomi Serbantez
- U.S. President's Malaria Initiative, Dar es Salaam, Tanzania
| | - Jovin Kitau
- World Health Organization, Country Office, Dar es Salaam, Tanzania
| | - Stephen M Magesa
- Pan African Mosquito Control Association (PAMCA), Dar es Salaam, Tanzania
- National Institute for Medical Research (NIMR), Amani Centre, Muheza, Tanzania
| | - William N Kisinza
- National Institute for Medical Research (NIMR), Amani Centre, Muheza, Tanzania
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