Volume 11, Number 11—November 2005
Dispatch
West Nile Virus Epidemic, Northeast Ohio, 2002
Table 2
Laboratory-based definitions used for confirmatory testing*†‡
Case | Definition |
---|---|
Confirmed WNV infection | WNV IgM MAC-ELISA positive and WNV PRNT titer >1:20 and WNV PRNT titer >2-fold than SLEV PRNT titer or |
WNV PRNT titer >1:20 and WNV PRNT titer >4-fold than SLEV PRNT titer |
|
Probable WNV infection |
WNV PRNT titer >2-fold than SLEV PRNT titer |
Previous SLEV infection |
SLEV PRNT titer >1:20 and SLEV PRNT titer >2-fold than WNV PRNT titer |
Probable nonspecific flavivirus infection | Negative WNV and SLEV PRNT results and |
Negative WNV IgM MAC-ELISA results and | |
Positive WNV, SLEV, or dengue IgG EIA results and | |
No history of YFV or JEV vaccination |
|
Previous infection | History of YFV or JEV vaccination, WNV IgM MAC-ELISA negative, and WNV and SLEV PRNT negative |
*WNV, West Nile virus; IgM, immunoglobulin M; MAC-ELISA, IgM antibody capture enzyme-linked immunosorbent assay; PRNT, plaque reduction neutralization test; SLEV, St. Louis encephalitis virus; EIA, enzyme immunoassay; YFV, Yellow fever virus; and JEV, Japanese encephalitis virus.
†All specimens referred for confirmatory testing were positive for WNV IgG during initial screening.
‡Case definitions were developed in consultation with the Centers for Disease Controla nd Prevention and the Ohio Department of Health.