Communicable Disease

West Nile Virus Health Advisories

HEALTH ALERT - August 8, 2002

From: David Persaud, M.D., M.P.H.
Medical Director

The Kent County Health Department is conducting increased surveillance of West Nile Virus (WNV) activity following the identification of sentinel birds found to be infected with WNV in Kent County. West Nile Virus is a vector-borne disease spread by infected mosquitoes. Although the risk of infection and illness among humans is generally low, anyone with exposure to mosquitoes is considered to be at risk for WNV infection.

According to U.S. Centers for Disease Control and Prevention guidelines for surveillance and control of West Nile Virus, 1) detection of WNV positive dead birds has been associated with an increased likelihood of human cases, and 2) counties with human cases have tended to have high dead bird surveillance indices (Since July 31, the Kent County Health Department has received over 400 citizen reports of dead birds in Kent County). In addition, in reviewing 1999-2000 West Nile Virus activity in the U.S., the CDC found the peak human risk for WNV infection occurred in mid to late August.

In accordance with these findings, the Kent County Health Department is seeking to increase surveillance of WNV among humans.

According to the CDC, most WNV infections in humans are mild, and symptoms include fever, headache, and body aches, occasionally with skin rash and swollen lymph glands. More severe infection may be marked by headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, paralysis, and, rarely, death. Persons over 50 years of age have the highest risk of developing severe illness as a result of WNV infection. In 1999-2000, the large majority of confirmed cases of human illness due to WNV infection were in persons with encephalitis.

Because West Nile Virus activity has been confirmed in Kent County, patients presenting with any of the above symptoms should warrant further evaluation to rule out West Nile Virus infection. Lumbar puncture should be considered for definitive diagnosis of WNV encephalitis in suspect patients. In particular:

  1. Patients over 50 years of age;
  2. Patients with a known recent history of mosquito exposure (e.g., recent history of camping, outdoor recreation or other outdoor activity);
  3. Patients with pre-existing chronic health conditions that may make them more susceptible to illness, and/or patients with immunosuppressive conditions;
  4. Any patient presenting with flu-like symptoms, or symptoms consistent with WNV infection.

Any patient identified as having laboratory-confirmed evidence of infection with West Nile Virus should be reported immediately to the Kent County Health Department Communicable Disease Unit at (616) 632-7190.

Many people infected with West Nile Virus may be asymptomatic and not seek medical care, and infection will resolve on its own. Patients with concerns about West Nile Virus infection should be advised that reducing exposure to mosquitoes has been identified as the most effective means of reducing individual risk of WNV infection. Additional information and links about West Nile Virus can be found on the Kent County Health Department web site at www.accesskent.com/health.

###