Unveiling the role of mosquito and human diel activity patterns in the risk of mosquito-borne disease infection

BackgroundMosquito-borne pathogens are transmitted through bites of female mosquito vectors that are actively seeking hosts for a blood meal and hosts, when either of them is infectious. Different mosquito species have different preferences for the time of the day/night when they actively seek blood meals. In the United States, the encounters between mosquito vectors and human hosts primarily take place outdoors. Socioeconomic factors such as occupation and income are major determinants of the hour of the day and total amount of time spent outdoors by different population groups. The aim of this study is to quantify: i) diel variations in the level of human exposure to mosquito vectors, and ii) exposure heterogeneities by human population group. MethodsWe collected both diel activity data for two mosquito vector species (Aedes aegypti and Culex quinquefasciatus) and time-use data for the United States. Then, we analyzed the diel overlap between the two at the population level and by human population group. ResultsFor both mosquito species, we found a substantial heterogeneity in their diel overlap with human outdoors activities. We estimated that the time periods with the highest risk of exposure to bites of Ae. aegypti are 7am-11am and 5pm-8pm, while the highest risk for Cx. Quinquefasciatus is 6am-7am and 6pm-9pm. Moreover, we found disparities in the exposure to mosquito vector species across different demographic groups. Workers with primarily outdoor occupations, males, and Hispanics/Latinos were shown to have higher levels of exposure as compared to the general population. In particular, we estimated that workers with primarily outdoor occupations were 7.50-fold (95%CI: 7.18-7.84) and 6.63-fold (95%CI: 6.09-7.35) more exposed to Ae. aegypti and Cx. quinquefasciatus than the general population, respectively. ConclusionThis study serves as a steppingstone to quantify the risk of exposure to mosquito vector species in the United States. The obtained results can be instrumental for the design of public health interventions such as education campaigns, which could contribute to improve health and health equity.