Evaluation of antigen-capture ELISA and immunohistochemical methods for avian surveillance of West Nile virus.
Accurate detection of West Nile virus (WNV) in corvids is essential for monitoring the spread of virus during the mosquito season. Viremia in corvids is very high, with titers approaching 10(8) viral particles/ml. In the presence of such marked viremia, the sensitivity of real-time reverse transcription-polymerase chain reaction (RT-PCR) analysis is unnecessary, and more cost-effective methods should be assessed. To this end, antigen-capture ELISA (ACE) and immunohistochemical (IHC) assays were evaluated. Skin, cloacal swab specimens, and feathers from corvids were tested by use of ACE, and results were compared with results obtained from use of real-time RT-PCR analysis. Of the 3 sample types, skin gave the best sensitivity (98%) and specificity (100%). Skin, brain, kidney, and spleen from corvids were analyzed by IHC, and results were compared with real-time RT-PCR results. Kidney and spleen were more often positive by use of IHC than were brain and skin tissue; however, IHC did not perform as well as ACE in the identification of virus-positive birds. Results of this study support the use of a skin sample in an ACE format as an effective surveillance method for corvids.
Wisconsin Veterinary Diagnostic Laboratory, Department of Bacteriology, University of Wisconsin-Madison, USA.
Jennifer A
JA
Godhardt
Kerry
K
Beheler
Michael J
MJ
O'Connor
T J
TJ
Whyte
Erik S
ES
Reisdorf
Susan J
SJ
Ubl
Philip N
PN
Bochsler
Kathy L
KL
Toohey-Kurth
D000818:Animals; D000956:Antigens, Viral / Q000032:analysis; D001715:Bird Diseases / Q000175:diagnosis* / Q000821:virology; D001921:Brain / Q000821:virology; D002988:Cloaca / Q000821:virology; D003362:Cost-Benefit Analysis; D046368:Crows; D004797:Enzyme-Linked Immunosorbent Assay / Q000191:economics / Q000379:methods / Q000662:veterinary*; D005241:Feathers / Q000821:virology; D007150:Immunohistochemistry / Q000191:economics / Q000379:methods / Q000662:veterinary*; D007668:Kidney / Q000821:virology; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000191:economics / Q000662:veterinary; D012867:Skin / Q000821:virology; D013154:Spleen / Q000821:virology; D014901:West Nile Fever / Q000175:diagnosis / Q000662:veterinary* / Q000821:virology; D014902:West Nile virus / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*
D000956:Antigens, Viral