Olaitan Olamide Omitola1, Cynthia Uchechukwu Umunnakwe2, Adedotun Ayodeji Bayegun2, Samuel Akinjide Anifowose2, Hammed Oladeji Mogaji3, Akinola Stephen Oluwole4, Simon Nnayere Odoemene5, Taiwo Sam Awolola6, Adebola Adedoyin Osipitan7, Sammy Olufemi Sam-Wobo2, Uwem Friday Ekpo8. 1. Department of Pure and Applied Zoology, Federal University of Agriculture, Abeokuta, Ogun, Nigeria. olaitanomitola@gmail.com. 2. Department of Pure and Applied Zoology, Federal University of Agriculture, Abeokuta, Ogun, Nigeria. 3. Department of Animal and Environmental Biology, Federal University Oye Ekiti, Ekiti, Nigeria. 4. COUNTDOWN Consortium, Sightsavers Nigeria Country Office, Kaduna, Nigeria. 5. Department of Biological Sciences, Adeleke University, Ede, Osun, Nigeria. 6. Molecular Entomology and Vector Control Research Laboratory, Public Health Division, Nigeria Institute of Medical Research, Lagos, Nigeria. 7. Department of Crop Protection, Federal University of Agriculture, Abeokuta, Ogun, Nigeria. 8. Department of Pure and Applied Zoology, Federal University of Agriculture, Abeokuta, Ogun, Nigeria. ufekpo@hotmail.com.
Abstract
BACKGROUND: The impact of single-dose mass drug administration (MDA) of ivermectin for onchocerciasis on mosquito populations was investigated in Ogun State, Nigeria. METHODS: Indoor and outdoor collection of mosquitoes was carried out in two intervention (IC) and two control communities (CC) at three different periods: pre-MDA (baseline), 2-3 days after MDA and 13-14 days after MDA. The density and parity rate of female Anopheles and Culex mosquitoes were determined and compared. Environmental and climatic data of study locations were obtained to perform generalized linear model analysis. RESULTS: A total of 1399 female mosquitoes were collected, including 1227 Anopheles and 172 Culex mosquitoes. There was a similar magnitude of reduction in the indoor density of Anopheles by 29% in the IC and CC 2-3 days post-MDA but the reduction in indoor parity rate was significantly higher (p = 0.021) in the IC, reducing by more than 50%. In the IC, observation of a significant reduction at 2-3 days post-MDA was consistent for both the indoor density (1.43 to 1.02) and indoor parity rate (95.35% to 44.26%) of Anopheles mosquitoes. The indoor parity rate of Anopheles remained significantly reduced (75.86%) 13-14 post-MDA. On the other hand, the indoor density of Culex increased from 0.07 to 0.10 at 2-3 days post-MDA while the indoor parity rate of Culex did not change. The outdoor density of Anopheles in the IC increased (p = 0.394) from 0.58 to 0.90 at 2-3 days post-MDA; a similar observation was consistent for the outdoor density (2.83 to 3.90) and outdoor parity rate (70.59% to 97.44%) of Culex, while the outdoor parity rate of Anopheles reduced from 85.71 to 66.67% at 2-3 days post-MDA. A generalized linear model showed that ivermectin MDA significantly caused a reduction in both the indoor density (p < 0.001) and indoor parity rate (p = 0.003) of Anopheles in the IC. CONCLUSION: Ivermectin MDA resulted in the reduction of both the survival and density of Anopheles mosquitoes. This has strong implications for malaria transmission, which depends strongly on vector survival.
BACKGROUND: The impact of single-dose mass drug administration (MDA) of ivermectin for onchocerciasis on mosquito populations was investigated in Ogun State, Nigeria. METHODS: Indoor and outdoor collection of mosquitoes was carried out in two intervention (IC) and two control communities (CC) at three different periods: pre-MDA (baseline), 2-3 days after MDA and 13-14 days after MDA. The density and parity rate of female Anopheles and Culex mosquitoes were determined and compared. Environmental and climatic data of study locations were obtained to perform generalized linear model analysis. RESULTS: A total of 1399 female mosquitoes were collected, including 1227 Anopheles and 172 Culex mosquitoes. There was a similar magnitude of reduction in the indoor density of Anopheles by 29% in the IC and CC 2-3 days post-MDA but the reduction in indoor parity rate was significantly higher (p = 0.021) in the IC, reducing by more than 50%. In the IC, observation of a significant reduction at 2-3 days post-MDA was consistent for both the indoor density (1.43 to 1.02) and indoor parity rate (95.35% to 44.26%) of Anopheles mosquitoes. The indoor parity rate of Anopheles remained significantly reduced (75.86%) 13-14 post-MDA. On the other hand, the indoor density of Culex increased from 0.07 to 0.10 at 2-3 days post-MDA while the indoor parity rate of Culex did not change. The outdoor density of Anopheles in the IC increased (p = 0.394) from 0.58 to 0.90 at 2-3 days post-MDA; a similar observation was consistent for the outdoor density (2.83 to 3.90) and outdoor parity rate (70.59% to 97.44%) of Culex, while the outdoor parity rate of Anopheles reduced from 85.71 to 66.67% at 2-3 days post-MDA. A generalized linear model showed that ivermectin MDA significantly caused a reduction in both the indoor density (p < 0.001) and indoor parity rate (p = 0.003) of Anopheles in the IC. CONCLUSION:Ivermectin MDA resulted in the reduction of both the survival and density of Anopheles mosquitoes. This has strong implications for malaria transmission, which depends strongly on vector survival.
Entities:
Keywords:
Endectocide; Ivermectin; Mosquito; Nigeria; Vector control