What boosts Aedes Aegypti mosquitoes in coastal ecuador?

A typical urban, arid street in Huaquillas, Ecuador.
A typical urban, arid street in Huaquillas, Ecuador. (Image courtesy of Sadie Ryan)

Aedes aegypti mosquitoes are important transmitters of viral infectious diseases such as dengue fever and Zika virus. These insects prefer to bite humans for a blood meal and lay their eggs in human-made containers such as water tanks, planters, or even old tires. Controlling for outbreaks of mosquito-borne diseases often means controlling for these mosquitoes, which underscores the need to learn how factors local to specific areas of human settlement promote or thwart Ae. aegypti survival.

University of Florida medical geographer Sadie Ryan and her lab group contributed to research in Huaquillas, Ecuador to better understand household-level factors associated with the presence of Ae. aegypti. Ryan is an associate professor in the UF College of Liberal Arts and Sciences and the UF Emerging Pathogens Institute.

Huaquillas is the largest coastal Ecuadorian city on the border with Peru, where controlling dengue fever outbreaks is a major public health goal. Investigators used special machines called backpack aspirators to collect mosquitoes in and around homes throughout the city. They sampled 63 households from 10 different areas between January and May of 2017 during the normal mosquito-borne disease transmission season. Specimen collections were paired with household interviews to collect information about living conditions, demographics, economics, travel, disease prevention actions, and city services.

The research team found that households had the most Ae. aegypti in February and the lowest prevalence in May. They also found that high mean weekly temperatures, and a time lag of one week after increased rainfall, were significantly correlated with Ae. aegypti presence. Surveys of homeowners also revealed that disruptions to piped water were positively linked to mosquito presence, while use of a septic tank was negatively linked. These findings are important for local health authorities, who can use information on timing and risk factors for mosquito presence in decision-making, and to tailor local mosquito control efforts in Huaquillas.

The findings are published in PLOS-NTD, and funding was provided by the National Science Foundation. 

Written by: DeLene Beeland