(C-041) Active Surveillance of Mosquito-borne Diseases in the United States

Background: Mosquito-borne diseases have long posed a threat to the health of people in the United States (US) and have become increasingly common with changing patterns in travel, climate, and land use. Over the past decade, there have been major outbreaks of mosquito-borne diseases such as West Nile and Zika Virus that have included locally acquired cases seen for the first time in the US. While states and territories report mosquito-borne disease cases for monitoring at the national level, reported cases underestimate the true burden of disease and are subject to lags in data availability.

Objectives: To assess the feasibility and capacity of Truveta to measure, in real time, the trends in mosquito-borne disease cases, particularly chikungunya, dengue, West Nile, and Zika, as compared to nationally reported case data.

Methods: Truveta is a growing collective of 30 US health systems that includes more than 120 million de-identified patients. This retrospective study identified four cohorts diagnosed with one of the following mosquito-borne diseases: chikungunya, dengue, West Nile, and Zika. Patients were followed from 1/1/2016-12/31/2024. Resulting trends were compared to the Center for Disease Control and Prevention (CDC) National Notifiable Diseases Surveillance System (NNDSS).

Results: A total of 8,112 patients were diagnosed with one of the four mosquito-borne diseases within the designated time period. The majority of patients were female (55%) and of white race (66%). Mean age varied by disease; Zika cases had the lowest at 31 years, followed by dengue at 46 years, chikungunya at 47 years, and West Nile at 49 years. Of patients with location data available, 51% were in the Southern US. Trends in West Nile cases show peaks in 2018 and 2021. Trends in dengue cases show a peak in 2019 and a consistent increase in yearly cases from 2021-2024. Trends Zika cases show a peak in 2016 followed by steady, low case counts from 2017-2024. Chikungunya cases remained low from 2016-2024. All of these trends are consistent with those seen in CDC’s NNDSS data, including national outbreaks.

Conclusions: The findings indicate that Truveta Data are comparable to the CDC NNDSS reports, as illustrated by four mosquito-borne diseases. Truveta Data is well-suited to support near real-time active surveillance studies of infectious diseases.