Health

Advisory

EVIDENCE OF WEST NILE VIRUS IN DELAWARE

The Delaware Division of Public Health (DPH) would like to alert the medical community of evidence of West Nile Virus (WNV) in Delaware.

To date, there have been no confirmed cases in humans in Delaware this season. However, two cases have been confirmed in chickens as part

of Delaware’s sentinel surveillance system. Additionally, seven wild birds have tested positive since July 8, 2012.

Approximately 80 percent of all people infected by WNV experience no symptoms. About 20 percent of those who become ill with WNV

typically have mild symptoms. Less than 1 percent of humans infected with WNV develop more serious symptoms which can result in long term

health effects or death. Infection should be considered in adults 50 years of age or older who have onset of unexplained encephalitis or

meningitis in late summer or early fall. The local presence of WNV enzootic activity or other human cases of WNV infection should further

raise the index of suspicion.

WNV in Delaware

West Nile virus first appeared in Delaware birds and horses in 2000. Delaware’s first confirmed human case of West Nile virus

occurred in 2002. In 2003, 17 human cases were confirmed, including two deaths. While there were no reported human cases in 2004, 2006,

and 2009, two cases were confirmed in 2005 and one in 2007, 2008 and 2011.

DPH Diagnostic Testing

The DPH Laboratory (DPHL) performs WNV testing for humans, birds and horses. Methods include antibody testing, as well as Polymerase

Chain Reaction (PCR) and culture. In humans, the preferred specimen is cerebrospinal fluid (CSF). CSF should be collected within 8 days

of illness onset, while serum specimens should be collected within 8-14 days of illness onset.  False positive antibody results for

WNV may occur in patients recently vaccinated for, or infected with, related flaviviruses (i.e., yellow fever, Japanese Encephalitis,

dengue)

• Please contact DPH Bureau of Epidemiology at 1-888-295-5156 to coordinate testing.
• Patient samples obtained at hospital labs in Delaware should be sent to the Delaware Public Health Laboratory (DPHL) for confirmatorytesting after consultation with the Bureau of Epidemiology. Please contact DPHL at 302- 223-1520 for courier pickup.
• Healthcare providers may also request WNV testing from commercial laboratories. These results should be confirmed at DPHL afterconsultation with the Bureau of Epidemiology. Please contact DPHL at 302- 223-1520 for courier pickup.

For More information:

• Clinical Information and Guidance (CDC): http://www.cdc.gov/ncidod/dvbid/westnile/clinicians/
• Specimen collection requirements: https://dhss.delaware.gov/dph/lab/files/spcollectionpro.pdf
• DPH Bureau of Epidemiology: 1-888-295-5156

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