How often, when, and where do people get bitten by mosquitoes? Characterizing human–mosquito contact using Bite Diary

Mosquito-borne pathogens are transmitted through mosquito bites, yet transmission risk is often assessed using only entomological indicators. This approach overlooks the key pathway of transmission, actual bite exposure, which is strongly shaped by human behavior, such as time spent outdoors, use of protective measures, and daily routines. Despite its importance, methods for measuring human bite exposure at fine temporal and behavioral scales remain limited. We used a smartphone-based bite reporting system (“Bite Diary”) together with residential mosquito trapping to evaluate how mosquito abundance and outdoor activity correspond to self-reported bite exposure in suburban Indian River County, Florida, USA. From July 2024 to June 2025, participants recorded bites and outdoor activity over a 4-day period, while mosquitoes were collected from their yards during the first 24 h of participation using CO 2 -baited BG-Sentinel and UV-light-based traps. In total, 83 individuals enrolled, 71 registered for the app, and 32 completed a follow-up online survey. Among 70 bite records, 92.9% and 73.6% occurred outdoors and at home, respectively. The average bite exposure rate was 0.29 bites/person/day (95% CI 0.09–0.49). Mosquito trapping in 78 yards yielded 3,788 female mosquitoes, with common species such as Aedes aegypti , Ae. albopictus, and Ae. taeniorhynchus, Culex nigripalpus , and Cx. quinquefasciatus . Mosquito abundance in yards was not associated with reported bite exposure, whereas time spent outdoors during the evening (17:00–21:00) was positively associated with bite exposure. Activities such as dog walking and gardening were frequently reported during bite exposure. These findings suggest that human behavior, particularly the timing and duration of outdoor activity, plays an important role in shaping bite exposure. They also demonstrate the feasibility of using a smartphone-based application to collect bite data. Currently, much of mosquito-borne disease research relies primarily on entomological metrics to assess risk, with limited integration of how people’s behaviors influence contact with mosquitoes. Our findings highlight the limitations of this approach. By linking human behavior to bite exposure, this study demonstrates the value of incorporating behavioral data alongside mosquito surveillance to better understand and predict transmission risk.