Parasites and Vectors (2013) 6 (319) - Impact of operational ...

Arthur Sovi, Roseric Azondékon, Rock Y. Aïkpon, Renaud Govoétchan, Filémon Tokponnon, Fiacre Agossa, Albert S. Salako, Frédéric Oké-Agbo, Bruno Aholoukpè, Mariam Okè, Dina Gbénou, Achille Massougbodji and Martin Akogbéto (2013)
Impact of operational effectiveness of long-lasting insecticidal nets (LLINs) on malaria transmission in pyrethroid-resistant areas
Parasites and Vectors 6 (319)
Abstract:
Background
A dynamic study on the transmission of malaria was conducted in two areas (R⁺ area: Low resistance area; R⁺⁺⁺ area: High resistance area) in the department of Plateau in South Eastern Benin, where the population is protected by Long Lasting Insecticidal Nets (LLINs). The aim of this study was to determine if the resistance of malaria vectors to insecticides has an impact on their behavior and on the effectiveness of LLINs in the reduction of malaria transmission.
Methods
Populations of Anopheles gambiae s.l. were sampled monthly by human landing catch in the two areas to evaluate human biting rates (HBR). Collected mosquitoes were identified morphologically and female Anopheles mosquitoes were tested for the presence of Plasmodium falciparum antigen as assessed using ELISA. The entomological inoculation rate (EIR) was also calculated (EIR = HBR x sporozoitic index [S]). We estimated the parity rate by dissecting the females of An. gambiae. Finally, window catch and spray catch were conducted in order to assess the blood feeding rate and the exophily rate of vectors.
Results
After 6 months of tracking the mosquito's behavior in contact with the LLINs (Olyset) in R⁺⁺⁺ and R⁺ areas, the entomological indicators of the transmission of malaria (parity rate and sporozoitic index) were similar in the two areas. Also, An. gambiae populations showed the same susceptibility to P. falciparum in both R⁺ and R⁺⁺⁺ areas. The EIR and the exophily rate are higher in R⁺ area than in R⁺⁺⁺ area. But the blood-feeding rate is lower in R⁺ area comparing to R⁺⁺⁺.
Conclusion
The highest entomological inoculation rate observed in R⁺ area is mostly due to the strong aggressive density of An. gambiae recorded in one of the study localities. On the other hand, the highest exophily rate and the low blood-feeding rate recorded in R⁺ area compared to R⁺⁺⁺ area are not due to the resistance status of An. gambiae, but due to the differences in distribution and availability of breeding sites for Anopheles mosquitoes between areas. However, this phenomenon is not related to the resistance status, but is related to the environment instead.
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Database assignments for author(s): Rock Aïkpon, Renaud Govoetchan, Arthur Sovi

Research topic(s) for pests/diseases/weeds:
control - general

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Culex quinquefasciatus		Benin
	Anopheles gambiae		Benin
	Culex annulirostris		Benin
	Aedes aegypti		Benin
	Anopheles funestus		Benin
	Anopheles pharoensis		Benin
	Anopheles coustani		Benin
	Anopheles ziemanni		Benin
	Aedes vittatus		Benin
	Culex tigripes		Benin
	Mansonia africana		Benin
	Aedes palpalis		Benin
	Culex nebulosus		Benin