The Los Angeles County Department of Public Health confirms its first West Nile virus (WNV) death of the 2015 season. The patient was an elderly male who lived in the San Gabriel Valley, had pre-existing health conditions, was hospitalized in late August and died this month. To date, 18 WNV infections, including 1 asymptomatic blood donor, have been documented in Los Angeles County.

“Mosquitoes are the primary pathway to human infection with West Nile virus and we are entering the period of increased transmission,” said Jeffrey Gunzenhauser, MD, MPH, Interim Health Officer for Los Angeles County. “West Nile can appear anywhere in Los Angeles County and we are urging people to take a few simple precautions that can greatly reduce the risk of mosquito bites. These precautions include getting rid of pools of stagnant water around your home and using a repellent containing DEET when outdoors in mosquito-prone areas, especially around dawn or dusk.”

In 2014, 218 human infections of WNV were reported in Los Angeles County, the second highest count documented since 2004. Most people with WNV infection have mild symptoms or none at all, do not seek medical care, and are not reported. Of those who showed symptoms and were reported to Public Health, 180 patients (90%) required hospitalization and 7 patients (3.5%) died. As of September 4, 2015, WNV activity has been detected in 118 mosquito collection sites, 12 dead birds, and 6 sentinel chickens across most of Los Angeles County.

About West Nile virus:

WNV is primarily spread to humans through the bite of an infected mosquito; mosquitoes can become infected by biting a bird that carries the virus. Most mosquitoes do not carry the virus and most people bitten by a mosquito are not exposed to the virus. The virus is not spread through person-to-person contact or directly from birds to humans.

In most cases, people who are infected with West Nile virus never become sick (80%) or have only very mild symptoms that include fever, headache, nausea, body aches, and a mild skin rash. Symptoms of WNV can appear within three to 12 days after infection. Fewer than one in 150 people who are bitten by an infected mosquito will become severely ill, according to the Centers for Disease Control and Prevention (CDC). In these cases, the virus can cause encephalitis and death. The elderly and those with weakened immune systems are most at risk for developing severe symptoms, which may require hospitalization. Recovery from an infection with the virus can take months to years; during that time, the individual may continue to have symptoms of fatigue, malaise, and depression. There is no specific treatment for this disease.

Decrease risk of infection:

* Do not allow water to collect and stagnate in old tires, flowerpots, swimming pools, birdbaths, pet bowls, or other containers. These are prime breeding grounds for mosquitoes.

* Keep swimming pools operating properly; drain water from pool covers.

* Stock garden ponds with goldfish or other mosquito-eating fish. These eat mosquito eggs and larvae.

* Empty and wash birdbaths and wading pools weekly.

* Avoid mosquito-infested areas at dawn and dusk.

* Wear long-sleeved shirts and long pants whenever you are outdoors, especially if you are older or have a weakened immune system.

* Apply repellents containing DEET, picaridin, IR3535, para-menthane-diol, or oil of eucalyptus according to label instructions. Repellents keep the mosquitoes from biting you.

* Make sure that your doors and windows have tight-fitting screens to keep out mosquitoes.

More information:

* Information on West Nile virus by phone: (800) 232-4636.

* Information on West Nile virus on the web: http://westnile.ca.gov/

* Los Angeles County Weekly WNV Epidemiology Report on the web: http://www.publichealth.lacounty.gov/acd/index.htm

Dead birds may be reported by calling (877) 968-2473 or logging onto http://www.westnile.ca.gov/report_wnv.php. Stagnant swimming pools or “green pools” should be reported to the Public Health Environmental Health Bureau at (626) 430-5200, or to a local vector control agency.

Where to call with questions about mosquitoes: Greater Los Angeles County Vector Control District: (562) 944-9656.

The Department of Public Health is committed to protecting and improving the health of the nearly 10 million residents of Los Angeles County. Through a variety of programs, community partnerships and services, Public Health oversees environmental health, disease control, and community and family health. Public Health comprises nearly 4,000 employees and has an annual budget exceeding $900 million. To learn more about the LA County Department of Public Health and the work they do, visit PublicHealth.LACounty.gov.