Table 2.
Criteria for case classification of human WNV infections (Commission Decision 2008/426/ EC).
| Clinical criteria |
|---|
| Any person with fever or one of the following: |
| Encephalitis |
| Meningitis |
| Laboratory criteria |
| Laboratory test for case confirmation |
| At least one of the following: |
| Isolation of WNV from blood/CSF |
| Detection of WNV nucleic acid in blood or CSF |
| WNV specific antibody response (IgM) in CSF |
| WNV IgM high titer and detection of WNV IgG, and confirmation by neutralization |
| Laboratory test for a probable case |
| WNV-specific antibody response in serum |
| (Laboratory results need to be interpreted according to flavivirus vaccination status) |
| Epidemiological criteria |
| At least one of the following two epidemiological criteria: |
| Animal to human transmission (residing, having visited or having been exposed to mosquito bites in an area where WNV is endemic in horses or birds) |
| Human to human transmission (vertical transmission, blood transfusion, transplants) |
| Case classification |
| Probable case |
| Any person meeting the clinical criteria and with at least one of the following two: |
| an epidemiological link |
| a laboratory test for a probable case |
| Confirmed case |
| Any person meeting laboratory criteria for case confirmation. |