Heterogeneous feeding patterns of Aedes aegypti in households in Iquitos, Peru

Heterogeneous biting by female mosquitoes can significantly alter transmission of mosquito-borne pathogens. Previous studies show Aedes aegypti, the primary vector of dengue viruses (DENVs), more frequently bite individuals with larger body surfaces. Because surface area increases with age up until approximately age 20, we expect positive linear relationship with age, biting and infection status. However, previous studies have shown an age bias in the distribution of bites. Factors such as sex and mosquito exposure time should, therefore, be used to analyze heterogeneous feeding patterns. Between October 2009 and November 2010, 2,035 interviews with 280 participants were conducted in 19 households in Iquitos, Peru. Interviews focused on anthropomorphic characteristics and time spent in houses. In the week following interviews adult mosquitoes were collected twice daily. Engorged abdomens were excised and participant DNA was obtained by cheek swab. All DNA was extracted using Qiagen extraction columns. Human DNA was amplified at 10 microsatellite loci, and allelic profiles identified using capillary electrophoresis. A computer program matched participant profiles to mosquito blood meals. Of 115 identified blood meal profiles, 101 have been matched to participants. Children under 15 received fewer than expected number of bites per person, and in this group age was positively, linearly correlated with body size, as well as number of bites received. This correlation was not seen with DENV infection status. We therefore reject the hypothesis that persons over 15 are at a higher risk of infection with dengue virus, due to increased exposure to mosquitoes.