Carson City's first human case of West Nile Virus in 2006 was announced Tuesday by Health and Human Services officials.
The individual, who is younger than 50, reportedly has the less-severe form of the disease, West Nile Fever.
One mosquito pool also tested positive for West Nile Virus in Douglas County recently, according to the Nevada Department of Agriculture.
Douglas County's Mosquito Control Supervisor Ron Lynch said the pool was collected from Minden-Tahoe Airport. Pools from Centerville Lane west of Highway 88, Glenbrook and Topaz Lake have tested negative, he said.
The disease has been found in 12 Nevada counties, most in Churchill County where 29 mosquito pools and four birds have tested positive. In Lyon County, there were 15 positive mosquito pools and seven in Pershing County.
Last year, a total of 148 positives were collected from Nevada mosquito pools through mid-September. Douglas County had six positive mosquito pools, Churchill had 22 and Lyon, 25.
During that same time period, Churchill and Douglas counties had three human cases each and Lyon County had seven.
Thirty-one human cases of West Nile Virus were confirmed in Nevada from July to October 2005, and one death was reported, according to information from the Centers for Disease Control and Prevention in Atlanta.
A seasonal epidemic that flares up in the summer and continues into the fall, West Nile Virus is spread by mosquitoes that acquire the infection when they feed on infected birds, according to the Centers for Disease Control.
Serious symptoms, including a potentially fatal encephalitis, will occur in about one in 150 people infected with West Nile, but the infection is so mild in 80 percent of the people contracting it that there are no symptoms.
About 20 percent will experience flu-like symptoms, including fever, headache, body aches, nausea, vomiting and sometimes swollen lymph glands or rash, according to the Centers for Disease Control.
It's important to wear insect repellent when outdoors, especially at dusk and dawn when mosquitoes are most active. Long sleeves and pants are recommended, and people should remove any standing water around their homes that could provide breeding grounds for mosquitoes.
Mosquito samples are also tested for other viruses, including St. Louis Encephalitis and Western Equine Encephalitis, a disease that affects both horses and humans.
Most people infected will have either no symptoms or a very mild illness. Most of the severe human cases begin with a sudden onset of fever, headache, stiff neck, vomiting and fatigue. There is no treatment for this type of encephalitis other than supportive care until the acute or severe phase of the illness has run its course, according to information from the Department of Agriculture.