title: West Nile virus and non-West Nile virus mortality and coinfection of American crows (Corvus brachyrhynchos) in California.
abstract: American crows are acutely sensitive to West Nile virus (WNV) infection, and crow mortality has been used in WNV surveillance to monitor enzootic transmission. However, non-WNV sources of mortality could reduce the reliability of crow death as a surveillance tool. Here, using a combination of histopathologic, toxicologic, virologic, and molecular techniques we describe causes of mortality in 67 American crows (Corvus brachyrhynchos) that were collected from a population in the Sacramento Valley of California in 2012 and 2013. Evidence of infectious disease was detected in 70% (47/67) of carcasses. The majority of deaths were linked to a suite of non-WNV viral, bacterial, and fungal infections (39%; 23/59 cases), WNV (36%; 24/67 cases), and an acute toxic event (25%; 15/59 cases). Coinfections were detected in 20% (12/59) of birds and frequently were associated with WNV and poxviral dermatitis. Inferences about WNV activity based on crow mortality should be supported by laboratory confirmation because crow mortality frequently can be caused by other infectious diseases or toxic events.
authors: Sarah S
authors: SS
authors: Wheeler
authors: Leslie W
authors: LW
authors: Woods
authors: Walter M
authors: WM
authors: Boyce
authors: Christina D
authors: CD
authors: Eckstrand
authors: Stanley A
authors: SA
authors: Langevin
authors: William K
authors: WK
authors: Reisen
authors: Andrea K
authors: AK
authors: Townsend
mesh_terms: D000818:Animals; D001715:Bird Diseases / Q000453:epidemiology* / Q000401:mortality / Q000821:virology; D002140:California / Q000453:epidemiology; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D002853:Chromatography, Liquid / Q000662:veterinary; D060085:Coinfection / Q000453:epidemiology / Q000401:mortality / Q000662:veterinary* / Q000821:virology; D003141:Communicable Diseases / Q000453:epidemiology / Q000209:etiology / Q000401:mortality / Q000662:veterinary*; D046368:Crows; D004785:Environmental Pollutants / Q000633:toxicity*; D062665:Epidemiological Monitoring / Q000662:veterinary; D008107:Liver Diseases / Q000453:epidemiology / Q000209:etiology / Q000401:mortality / Q000662:veterinary; D015995:Prevalence; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D012621:Seasons; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000662:veterinary; D014901:West Nile Fever / Q000453:epidemiology* / Q000401:mortality / Q000821:virology; D014902:West Nile virus / Q000302:isolation & purification*
chemical_list: D004785:Environmental Pollutants