Posted by Vector and Vector-borne Disease Committee
July 25, 2022
Cynthia Hopf, Elizabeth Bunting, Anne Clark, and Sara Childs-Sanford
From the Janet L. Swanson Wildlife Hospital and the Department of Clinical Sciences, College of Veterinary Medicine (Hopf, Childs-Sanford), and the Department of Population Medicine and Diagnostic Sciences (Bunting), Cornell University, Ithaca, NY 14853, USA; and the Department of Biological Sciences, Binghamton University, Binghamton, NY 13902, USA (Clark).
Journal of Avian Medicine and Surgery 36(1), 85-91, (2 May 2022). https://doi.org/10.1647/20-00112
Abstract [condensed]. … American crows with WNV infections are received and treated at the Janet L. Swanson Wildlife Hospital (Cornell University, Ithaca, NY, USA) on a regular basis during the summer and fall and have historically had a 100% mortality rate. The 5 American crows in this case series were tested, when possible, by polymerase chain reaction (PCR) and plaque reduction neutralization on admission and monitored with both PCR and plaque reduction neutralization throughout their rehabilitation process. Four of the 5 birds had a negative PCR test before release, and 1 bird had a “suspect” positive PCR test result before release. One of the crows was confirmed to have survived for at least 2.5 years after release. Viral shedding was documented up to 93 days after initial hospitalization, which is longer than any previous report of WNV shedding in an American crow.
Note: The study documents the survival of some crows after infection with WNV. Expansion of this trend may reduce the sensitivity of the dead bird surveillance program and perhaps attenuate WNV amplification through increasing flock immunity.