Health officials in Dallas County are reporting the first human case of West Nile virus (WNV) infection for the 2016 season. The Irving, TX resident was diagnosed with West Nile neuroinvasive disease.

Dallas County, TX map Image/David Benbennick via Wikimedia Commons
Dallas County, TX map
Image/David Benbennick via Wikimedia Commons

West Nile virus is a mosquito-borne disease that can cause encephalitis, a brain inflammation. West Nile virus was first detected in North America in 1999 in New York. Prior to that it had only been found in Africa, Eastern Europe, and West Asia.

According to the CDC, approximately 80 percent of people (about 4 out of 5) who are infected with WNV will not show any symptoms at all.

Up to 20 percent of the people who become infected have symptoms such as fever, headache, and body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin rash on the chest, stomach and back. Symptoms can last for as short as a few days, though even healthy people have become sick for several weeks.

About one in 150 people infected with WNV will develop severe illness. The severe symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. These symptoms may last several weeks, and neurological effects may be permanent.

There is no specific treatment for WNV infection.

Dallas County Health and Human Services (DCHHS) reports the preliminary mosquito vector index for the week ending July 2nd was 0.51, which meets thresholds of WNV activity which have been historically associated with large WNV epidemics of human illness locally.

In 2012, 398 cases of WNV infection were reported in Dallas County, including 20 deaths.