Dengue Serotypes Circulating in Aedes aegypti and Humans in a Poor or Peripheral Neighborhood at Reynosa, Mexico

Abstract

Eleven entomological variables were correlated with households seropositive (Y= 1) or seronegative (Y= 0) for dengue virus depending on the percentage of seropositive to total participants per household. DENV serotypes were identified in mosquito vectors. Three entomologic (spring, summer, and fall) and two serologic surveys (spring and fall) were done in 77 households at Reynosa, Mexico in 2014. Numbers of water-filled containers, larvae, and pupae were counted per household, and adult Aedes aegypti (L.) were collected with a backpack aspirator after landing on humans. In spring and fall, incidence of IgG and IgM dengue antibodies was determined per household and DENV serotypes in mosquitoes collected indoors. The households were infested with 1,573 female and 1,142 male Ae. aegypti. About 56 and 46% of 322 residents were participants in spring and fall, respectively, resulting in 117 and 95 positive cases for IgG/IgM in 68 and 62% of seropositive households. Recent transmission occurred in 8% of households with three IgM-positive participants and three IgG seroconversions, and all seropositive samples were DENV-2. A multivariate logistic regression indicated host-seeking females were the only explanatory variable linked to 48 seropositive households in fall, with 85% (289) clumped in 24 households. Host-seeking female mosquitoes also were correlated linearly with the number of IgG/IgM cases per household where an increase in 50 mosquitoes matched one IgG/IgM case. DENV -1 was detected in one pool of Ae. aegypti, and in another of Aedes albopictus Skuse. DENV -2 was amplified (10^7 RNA copies per milliliter) in one pool of 10 male Ae. aegypti, and at 3.40 log 10^4 in one male Ae. albopictus. DENV-1 and DENV-2 circulating in humans and mosquitoes were determined, with vertical cycles in both species of mosquito vector.