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. 2016 May 10;43(3):158–167. doi: 10.1159/000446219

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.