Health district reports year’s first human West Nile case

A Clark County man has become the first documented West Nile virus patient of 2015 in Southern Nevada.

The man over the age of 50 has the more serious form of the illness, according to the Southern Nevada Health District.

West Nile infection is caused by a virus carried by mosquitoes. Most people infected don't experience any signs or symptoms or only minor ones, such as fever and mild headache. However, some people develop a life-threatening illness that includes swelling of the brain.

Mild signs and symptoms of a West Nile virus infection generally go away on their own. Serious symptoms, such as a severe headache, fever, disorientation or sudden weakness, require immediate attention.

Environmental health specialists routinely survey known breeding sources for mosquitoes and trap them for identification and disease analysis.

The health district has collected West Nile positive mosquitoes this year in 22 local ZIP codes: 89011, 89012, 89014, 89025, 89027, 89029, 89031, 89074, 89107, 89113, 89117, 89118, 89119, 89123, 89128, 89129, 89130, 89131, 89134, 89143, 89146 and 89147.

West Nile virus can be prevented by using insect repellants and eliminating sources of standing water that support mosquito breeding. To prevent mosquito bites and to eliminate breeding sources:

— Apply an insect repellent containing DEETa chemical (N,N-diethyl-meta-toluamide) used as the active ingredient in many insect repellents. DEET can irritate the eyes, nose and mouth, but not the skin. Repellents containing picaridin and oil of lemon eucalyptus also have some efficacy. However, DEET is the best-studied and most-effective repellant available.

— Wear pants and long-sleeved shirts when outdoors.

— Avoid spending time outside when mosquitoes are most active, at dawn or dusk.

— Eliminate areas of standing water, including bird baths, "green" swimming pools, and sprinkler runoff, which support mosquito breeding.

In the past 10 years, 83 West Nile virus cases were reported by the health district, and six people died from the illness.

In addition to West Nile virus, mosquitoes are also tested for Western equine encephalitis and St. Louis encephalitis, relatively rare infections with no preventative drugs or specific treatments beyond supportive measures, but neither virus has been detected in Southern Nevada this year.

Contact Steven Moore at smoore@reviewjournal.com or 702-380-4563.