Survival and Release of 5 American Crows (Corvus brachyrhynchos) Naturally Infected With West Nile Virus

Hopf, Cynthia; Bunting, Elizabeth M.; Clark, Anne; Childs-Sanford, Sara E.

doi:10.1647/20-00112

Cited by 1 publication

(1 citation statement)

References 29 publications

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“…West Nile virus immunity in other species such as corvids is not well understood or extensively studied. Although reports of American Crows recovering from WNV infection have been documented recently [ 86 ], they have continued to signal WNV activity in the DBSP, in agreement with the finding that current WNV strains WN02 and SW03 cause high mortality in corvids similar to the original introduced strain (NY99) in the U.S. [ 51 ]. A decline in most corvids and House Sparrow populations in recent years may indicate continued susceptibility; however, birds surviving infection probably develop permanent immunity, which helps to dampen WNV activity in the cyclic trends as already mentioned [ 87 ].…”

Section: Discussionsupporting

confidence: 69%

Epidemic versus endemic West Nile virus dead bird surveillance in California: Changes in sensitivity and focus

et al. 2023

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Since 2003, the California West Nile virus (WNV) dead bird surveillance program (DBSP) has monitored publicly reported dead birds for WNV surveillance and response. In the current paper, we compared DBSP data from early epidemic years (2004–2006) with recent endemic years (2018–2020), with a focus on specimen collection criteria, county report incidence, bird species selection, WNV prevalence in dead birds, and utility of the DBSP as an early environmental indicator of WNV. Although fewer agencies collected dead birds in recent years, most vector control agencies with consistent WNV activity continued to use dead birds as a surveillance tool, with streamlined operations enhancing efficiency. The number of dead bird reports was approximately ten times greater during 2004–2006 compared to 2018–2020, with reports from the Central Valley and portions of Southern California decreasing substantially in recent years; reports from the San Francisco Bay Area decreased less dramatically. Seven of ten counties with high numbers of dead bird reports were also high human WNV case burden areas. Dead corvid, sparrow, and quail reports decreased the most compared to other bird species reports. West Nile virus positive dead birds were the most frequent first indicators of WNV activity by county in 2004–2006, followed by positive mosquitoes; in contrast, during 2018–2020 mosquitoes were the most frequent first indicators followed by dead birds, and initial environmental WNV detections occurred later in the season during 2018–2020. Evidence for WNV impacts on avian populations and susceptibility are discussed. Although patterns of dead bird reports and WNV prevalence in tested dead birds have changed, dead birds have endured as a useful element within our multi-faceted WNV surveillance program.

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Section: Discussionsupporting

confidence: 69%