Indoor Resting Behavior of Aedes aegypti (Diptera: Culicidae) in Acapulco, Mexico.

The markedly anthropophilic and endophilic behaviors of Aedes aegypti (L.) make it a very efficient vector of dengue, chikungunya, and Zika viruses. Although a large body of research has investigated the immature habitats and conditions for adult emergence, relatively few studies have focused on the indoor resting behavior and distribution of vectors within houses. We investigated the resting behavior of Ae. aegypti indoors in 979 houses of the city of Acapulco, Mexico, by performing exhaustive indoor mosquito collections to describe the rooms and height at which mosquitoes were found resting. In total, 1,403 adult and 747 female Ae. aegypti were collected, primarily indoors (98% adults and 99% females). Primary resting locations included bedrooms (44%), living rooms (25%), and bathrooms (20%), followed by kitchens (9%). Aedes aegypti significantly rested below 1.5 m of height (82% adults, 83% females, and 87% bloodfed females); the odds of finding adult Ae. aegypti mosquitoes below 1.5 m was 17 times higher than above 1.5 m. Our findings provide relevant information for the design of insecticide-based interventions selectively targeting the adult resting population, such as indoor residual spraying.

Evidence of vertical transmission and co-circulation of chikungunya and dengue viruses in field populations of Aedes aegypti (L.) from Guerrero, Mexico.

BACKGROUND: We report results of the entomo-virological surveillance system in Aedes aegypti local populations performed by the Ministry of Health of Guerrero. METHODS: Indoor-adult Ae. aegypti collected at Acapulco, Zihuatanejo, Coyuca de Benitez and Atoyac de Alvarez (dry season, 2015) were processed for dengue virus (DENV) and chikungunya virus (CHIKV) using RT-PCR. RESULTS: We identified different seroptypes of DENV (2, 3 and 4), CHIKV and their co-circulation in field-caught mosquitoes across a significant geographic area. Pools of males were positive for CHIKV and DENV 3 and 4 suggesting vertical transmission. CONCLUSIONS: Entomo-virological surveillance in Guerrero has identified early circulation of CHIKV and DENV and provided a trigger for timely and focalized vector control actions.

Arbovirus Surveillance and First Report of Chikungunya Virus in Wild Populations of Aedes aegypti from Guerrero, Mexico.

We carried out dengue (DENV) and chikungunya virus (CHIKV) surveillance in wild populations of Aedes aegypti from Guerrero, Mexico, from 2012 to 2014 following a standard national protocol of the Mexican Dengue Control Program. A total of 284 pools (15-30 specimens/pool) of female mosquitoes were tested with real-time reverse transcriptase-polymerase chain reaction to detect DENV and CHIKV. We report for the 1st time the detection of CHIKV from field-collected mosquitoes at Acapulco and Juchitán in 2014. Results from DENV are also reported.

Natural vertical transmission of dengue-1 virus in Aedes aegypti populations in Acapulco, Mexico.

We carried out dengue virus surveillance in Aedes aegypti populations from 47 neighborhoods of Acapulco during the rainy season of 2011 following a standard national protocol and as an improvement of the entomological surveillance of the Mexican Dengue Control Program. A total of 4,146 Ae. aegypti adults collected indoors and/or emerged from eggs, larvae, or pupae from households with dengue reports (probable or confirmed cases), were grouped into pools and processed using a standardized serotype-specific 4-plex real-time reverse transcriptase-polymerase chain reaction assay. Overall, only 2 (0.9%) of 226 pools of Ae. aegypti adults (1 pool of adults emerged from field-collected larvae, and another of indoor-collected adults) were positive for dengue virus 1 (DENV-1). This is appears to be the 1st report of evidence on the vertical and transovarial transmission of DENV-1 in field-caught Ae. aegypti in Mexico.