Posted by Vector and Vector-borne Disease Committee
April 19, 2023
Leslie Foss*, Tina Feiszli, Vicki L. Kramer, William K. Reisen, Kerry Padgett.
*Leslie.Foss@cdph.ca.gov
PLoS ONE April 6, 2023 https://doi.org/10.1371/journal.pone.0284039
Abstract [condensed]
Since 2003, the California West Nile virus (WNV) dead bird surveillance program (DBSP) has monitored publicly reported dead birds for WNV surveillance and response. We examined DBSP data from the early epidemic years (2004–2006) with recent endemic years (2018–2020) to characterize changes in program operations, patterns of dead bird reports, and WNV prevalence among dead birds and their utility as early indicators of WNV activity. In recent years fewer agencies collected dead birds for testing, but updated protocols enhanced the efficiency of the program. The number of dead bird reports was approximately ten times lower during 2018–2020 compared to 2004–2006; reports from the Central Valley and parts of Southern California decreased the most. Dead corvid, sparrow, and quail reports decreased the most compared to other bird species reports. In the early years, WNV positive dead birds were the most frequent first indicators of WNV activity; in contrast, during 2018–2020 mosquitoes were the most frequent first indicators. Evidence for WNV impacts on avian populations and susceptibility are also discussed.
Note: Despite declines in the number of birds reported by the public, dead bird surveillance remains important to better understand changes in WNV ecology and adds critical data to a comprehensive environmental surveillance program.