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

Background Mosquito-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. Methods We 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. Results For 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. Conclusion This 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. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study did not receive any funding ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The Institutional Review Board of Indiana University waived ethical approval for this work (IRB #23194). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced are available online at https://www.bls.gov/tus/ and doi: 10.1371/journal.pntd.0011074.