268 - VectorSurv Origins

Abstract: The assessment of disease risk in time and space must be based on monitoring key metrics that track amplification. Epidemiological investigations of outbreaks of encephalitis in the Yakima Valley, Washington, and Kern County, California, discovered that western equine and St. Louis encephalitis viruses were the primary pathogens and were amplified within an enzootic cycle with Culex tarsalis and the Cx. pipiens complex as the primary vectors and passeriform birds as the primary hosts; humans and horses were dead-end hosts. In California, a statewide surveillance program for these arboviruses was developed by the California Department of Health Services (now Department of Public Health, CDPH) in collaboration with the Mosquito and Vector Control Association of California (MVCAC) and the University of California (UC) monitoring mosquito abundance and infection, seroconversions in sentinel chickens, and equine and human cases. This program documented that these viruses were endemic, but outbreaks were sporadic and associated with periods of high vector abundance driven by climate variation. The time required for diagnostics and reporting limited a timely, data-driven intervention response. The arrival of West Nile virus which posed a greater public-health threat prompted a number of improvements to surveillance and data management. Through the established partnership of CDPH, MVCAC, and UC Davis, and grant funding from NOAA, NASA, and CDC, California’s surveillance system moved into the modern era, including rapid statewide testing of mosquitoes and dead birds through RT-PCR, digitization of historical data, transition of reporting to web-based data management and sharing, and an adoption of a statewide response plan and risk assessment model that included climate variables and all surveillance elements. These advances in CalSurv paved the way for VectorSurv’s future growth to enable evidence-based decision-making at local to national scales.