Influence of Household Roof Types on the Development of Plasmodium vivax in Anopheles stephensi Mosquitoes.

Abstract

Urbanization and microclimate variation in cities can influence mosquito behavior and parasite development, thus affecting malaria transmission. This study investigates how the impact of microclimate variations due to household roof types can aid in the survival of Anopheles stephensi and the development of Plasmodium vivax in an urban slum setting. Understanding these vital environmental interactions is essential for devising effective control strategies to achieve malaria elimination. Anopheles stephensi (F1) mosquitoes were membrane-fed with blood collected from P. vivax-infected patients before (day 0) and during (day 1) antimalarial treatment. The parasite development and mosquito survival were monitored in simulated microclimatic conditions of a variety of household roof types (thatched, asbestos, tiled) against standard laboratory conditions. Mosquito dissections were undertaken to detect oocysts and sporozoites in An. stephensi mosquitoes (oocyst: day 3-5, sporozoites: day 7-11). The maximum number of oocysts were detected in infected mosquitoes in thatched-roof conditions, whereas the largest oocyst was in the asbestos roof type. Circumsporozoite-ELISA results indicated the presence of sporozoites in infected mosquitoes for up to 29 days under standard conditions, 18 days in thatched-roof and asbestos roof conditions, and 14 days in tiled conditions. The univariate binary logistic regression model indicated a significant influence of microclimatic conditions of thatched roofs on parasite development. The Kaplan-Meier survival analysis revealed that the median survival of P. vivax-infected An. stephensi in thatched-roof conditions was 14 days, followed by asbestos (11 days) and tiled (10 days) roof conditions. In conclusion, thatched-roof houses were favorable for the development and survival of P. vivax-infected An. stephensi.