The Impact of Flooding on Malarial Transmission within Roadway Communities in the Peruvian Amazon

Abstract

Severe flooding inundated the lowlands of Peru between 2011 and 2012. The rainfall and ensuing elevation in river levels coincided with a marked increase in human malaria. This study analyzes sampled Anopheles mosquitoes in twenty communities located on a new roadway system within the lowland Peruvian Amazon over a period of twelve months. 3,913 mosquitoes were captured and tested for Plasmodium sporozoite proteins via laboratory ELISA. Over eighty five percent (85%) of the samples were Anopheles darlingi. Half of the sampled communities reported at least one positive mosquito during the four rounds of collection. Transmission intensity was highly variable between communities, including the observation of spatial clustering of mosquito infectivity between communities near block sixteen (16). A negative binomial regression demonstrated smaller communities, closer to a river, were subject to higher mosquito densities. These same geographic sites did not exhibit statistically significant predicted rates of mosquito infectivity. Therefore, no additional conclusions can be made with regards to river distance on malaria burden. However, the observed heterogeneous patterns of malaria in collection sites could be driven by farm-to-market travel, previously explored in other investigations.