A CONFIRMED case of West Nile virus infection in a patient with clinically compatible disease is determined by meeting one of the following criteria: |
- Isolation of virus from, or demonstration of specific viral antigen or nucleic acid in, tissue, blood, CSF, or other body fluid, or
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- Fourfold or greater change in virus-specific quantitative antibody titers (PRNT) in paired sera, or
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- Virus-specific IgM antibodies (MAC-ELISA) in serum with confirmatory virus-specific neutralizing antibodies (PRNT) in the same or a later specimen, or
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- Virus-specific IgM antibodies in the CSF (MAC-ELISA) and negative IgM in the CSF for other arboviruses endemic to the region where the exposure occurred
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A PROBABLE case of West Nile virus is considered if: |
- Virus-specific IgM antibodies (MAC-ELISA) are present in CSF or serum but no other testing (eg, PRNT, PCR) is performed
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