Antecedent and real-time measures of arbovirus outbreak risk in California

Previous seasons vector abundance, winter climate variation and avian maintenance host herd immunity were related to vernal West Nile virus amplification. Remotely and ground sensed climate variables were used by NASA’s Terrestrial Observation and Prediction System to provide daily layers of environmental conditions in California. These data in combination with weekly measures of mosquito abundance anomalies and infection, sentinel chicken seroconversions and dead bird reports were used to monitor risk of human cases in near real-time. Risk estimates tracked human cases well and usually provided several weeks early warning prior to the on-set on cases in both urban Los Angeles and Bakersfield.