PHYSICIAN ALERT: WEST .NILE VIRUS

GOVERNMENT OF THE DISTRICT OF COLUMBIA DEPARTMENT OF HEALTH

The Department of Health (DOH) continues to emphasize the importance of active surveillance for human cases of West Nile Virus (WNV).

Clinical Description:

Arboviral infections may be asymptomatic or may result in illnesses of variable severity sometimes associated with the central nervous system (CNS). Clinical syndrome can range from febrile headache to aseptic meningitis to encephalitis. Arboviral meningitis is characterized by fever, headache, stiff neck, and pleocytosis. Arboviral encephalitis is characterized b fever, headache and alter red mental status ranging from confusion to coma with or without signs of brain dysfunction.

Clinical criteria:

I Neuroinvasive disease

·          Fever greater than or equal to 100.4° F or 38°C) as reported by the patient or a health-care provider. AND

·         Meningitis, encephalitis. acute flaccid paralysis or other acute signs of central or peripheral neurologic dysfunction, as documented by a physician. AND

·         Absence of a more likely clinical explanation.

II Non-neuroinvasive disease

Fever greater than or equal to lOO.4°F or 38'C) as reported by the patient or a health-care provider, AND

·         Absence of neuroinvasive disease. AND

·         Absence of a more likely clinical explanation.

Laboratory criteria:

I. Confirmed

·         Isolation of virus from, or demonstration of specific viral antigen or nucleic acid in, tissue, blood. CSF or other body fluid. OR

·         Four-fold or greater change in virus-specific quantitative antibody titers in paired sera. OR

·         Virus-specific IgM antibodies in serum with confirmatory virus-specific neutralizing antibodies in the same or a later specimen OR

·         Virus-specific IgM antibodies in CSF and a negative result for other IgM antibodies in CSF for arboviruses endemic to the region where exposure occurred.

II. Probable

·         Virus-specific IgM antibodies in CSF or serum but with no other testing.

Case Definitions: A case must meet one or more of the above clinical criteria and one or more of the above laboratory criteria.

Send Case Report Forms via FAX to:  (202) 442-8060

Laboratory testing information: (202)535-2323

Questions: (202)442-8141

Testing for West Nile Virus (WNV): Please submit >5.0 ml of serum (or plasma for virus isolation) and > 1.0ml of CSF. Please do not submit whole blood. Convalescent specimens (2 weeks after initial specimen) should be clearly labeled as such so appropriate testing can be done. A copy of the case report must accompany each specimen/set of specimens submitted for testing.