Exploring the utility of social-ecological and entomological risk factors for dengue infection as surveillance indicators in the dengue hyper-endemic city of Machala, Ecuador

Abstract

The management of mosquito-borne diseases is a challenge in southern coastal Ecuador, where dengue is hyper-endemic and co-circulates with other arboviral diseases. Prior work in the region has explored social-ecological factors, dengue case data, and entomological indices. In this study, we bring together entomological and epidemiological data to describe links between social-ecological factors associated with risk of dengue transmission at the household level in Machala, Ecuador. Households surveys were conducted from 2014–2017 to assess the presence of adult Aedes aegypti (collected via aspiration) and to enumerate housing conditions, demographics, and mosquito prevention behaviors. Household-level dengue infection status was determined by laboratory diagnostics in 2014–2015. Bivariate analyses and multivariate logistic regression models were used to identify social-ecological variables associated with household presence of female Ae. aegypti and household dengue infection status, respectively. Aedes aegypti presence was associated with interruptions in water service and weekly trash collection, and household air conditioning was protective against mosquito presence. Presence of female Ae. aegypti was not associated with household dengue infections. We identified shaded patios and head of household employment status as risk factors for household-level dengue infection, while window screening in good condition was identified as protective against dengue infection. These findings add to our understanding of the systems of mosquito-borne disease transmission in Machala, and in the larger region of southern Ecuador, aiding in the development of improved vector surveillance efforts, and targeted interventions.

Housing Risk Factors of Four Tropical Neglected Diseases: A Brief Review of the Recent Literature

“…A study by Lippi et al [ 36 ] from a dengue hyper-endemic city (Machala) in Ecuador showed that Aedes aegypti presence was associated inter alia with interruptions in water service (OR = 1.7, 95% CI 1.10–2.55), whereas the existence of air-conditioning diminished the presence of Aedes aegypti. When comparing households with dengue infection to households without, shaded patios were a significant risk factor (OR = 3.8, 95% CI 1.3–11.5), whereas window screens in good condition were a protective factor (OR = 0.3, 95% CI 0.1–0.8).…”

Household and climate factors influence Aedes aegypti presence in the arid city of Huaquillas, Ecuador

“…aegypti at the household level has been found in previous studies, and points to the fundamental and vital role reliable water supply and urban infrastructure play in Ae . aegypti endemic environments [ 80 ]. Notably, the link between interruptions in water service and either Ae .…”

“…Notably, the link between interruptions in water service and either Ae . aegypti presence or dengue fever risk has been documented previously in Ecuador, in the coastal city of Machala [ 38 , 80 ]. Unreliable water sources underpin many of the water storage behaviors that create suitable ovipositional sites for Ae .…”

“…aegypti presence or dengue fever were also observed in Machala and Guayaquil, two other coastal cities in Ecuador, possibly indicating that access to municipal services like trash collection may be a proxy indicator of built environments in Ecuador that are easily exploited by Ae . aegypti for reproduction [ 44 , 80 ].…”

Eco-health survey effort to diagnose readiness for sustainability dengue prevention and control

“…The number of family members living in a house will affect the health of its residents, while the density of occupancy, in turn, greatly affects the presence of Aedes aegypti mosquitoes in a place of residence [14]. The denser the household, the more dirty the house and the higher the CO2 levels which can be a factor driving the arrival of mosquitoes [21].…”