"We continue to see increased transmission of this virus that can cause serious disease," said Jonathan E. Fielding, MD, MPH, Director of Public Health and Health Officer. "Taking a few simple precautions can greatly reduce the risk of mosquito bites, the primary pathway to human infection. West Nile can appear anywhere in Los Angeles County, or around the state, and we are urging people to take precautions, such as getting rid of pools of stagnant water around their homes, and using a repellant containing DEET when outdoors in mosquito prone areas, especially around dawn or dusk."

In most years, the risk of WNV decreases by October. In 2012, WNV cases continued to be reported through late November. In October 2013, warm fall temperatures throughout Los Angeles County continue to support mosquito breeding and WNV transmission prolonging the season for WNV infection that could extend throughout November. This year, risk of infection has been especially elevated in the South Bay. Several mosquito abatement agencies in Southern California, including the Greater Los Angeles County Vector Control District (GLACVCD), Los Angeles County West Vector Control District, Antelope Valley and the San Gabriel Valley Mosquito and Vector Control District, have been cautioning residents that this year is a particularly active year for mosquitoes carrying WNV.

To date, 139 WNV infections have been reported in Los Angeles County. Of those who showed symptoms, 80% required hospitalization and 6% were fatal. As of October 17, 2013, WNV has been detected in 397 mosquito pools and 304 dead birds in Los Angeles County. The wide-ranging distribution of our human cases demonstrates that the virus can affect any location. Even though the vast majority of infected individuals do not show symptoms, or have a mild illness, those over 50 years of age and those with immunocompromising medical conditions are at increased risk of serious WNV infection that can affect the brain and spinal cord.

• Dead birds may be reported by logging onto http://publichealth.lacounty.gov/vet/disintro.htm.
• 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.

Physicians and other Medical Providers

• Patients presenting with febrile illness, neurological conditions suggesting meningitis, asymmetric paralysis and encephalitis should be evaluated for WNV infection.
• WNV related infections should be considered through late November 2013.
• Advise all patients (especially, those over 50 years and with immunocompromising conditions) on the importance of mosquito protection and the risk of WNV infection.

Senior Centers/ Shelters/Homeless Advocates

• Ensure senior centers and shelters have appropriate screening to prevent mosquito exposure.
• Provide health educational material to educate clients on the importance of mosquito protection.
• Health information on WNV prevention can be obtained at http://westnile.ca.gov/ and also by calling Acute Communicable Disease Control Health Educators at 213- 240-7941 during business hours.
• Consult your local mosquito abatement district for information on mosquitoes

About West Nile Virus:

• Mosquitoes infected with WNV transmit WNV infection to humans.
• WNV is not spread though person-to-person contact or directly from birds to humans.
• In most cases, people who are infected with West Nile virus never become sick, or have only very mild symptoms that include fever, headache, nausea, body aches, and a mild skin rash.
• Symptoms of WNV could appear within three to 12 days after infection.
• Fewer than one in 150 people who are bitten by an infected mosquito become severely ill, according to the Centers for Disease Control and Prevention (CDC). In these rare cases, the virus can cause encephalitis and even death.
• People over 50 years of age and those with weakened immune systems are most at risk for developing severe symptoms, which may require hospitalization.
• Recovery from any infection with the virus can take months to years, and some individuals may never fully recover.
• There is no specific treatment for this disease.

Decrease risk of infection:

• Avoid mosquito-infested areas at dawn and dusk.
• Wear long-sleeved shirts and long pants whenever you are outdoors.
• Repellants containing DEET, picaridin, or oil of eucalyptus, when used as labeled, are effective defenses against mosquitoes.
• Check your window screens for holes.
• 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.
• Clean and chlorinate swimming pools; 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.

More information:

• Information on West Nile Virus by phone: (800) 975-4448.
• Information on West Nile Virus on the web: http://westnile.ca.gov/

Where to call with questions about mosquitoes:

• Greater Los Angeles County Vector Control District: (562)944-9656
• Los Angeles County West Vector Control District: (310) 915-7370
• San Gabriel Valley Mosquito and Vector Control District:(626) 814-9466
• Antelope Valley Mosquito and Vector Control District: (661) 942-2917
• Compton Creek Mosquito Abatement District: (310) 933-5321
• Pasadena City Health Department: (626) 744-6004
• City of Long Beach Vector Control Program: (562) 570-4132

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 $750 million. To learn more about Public Health and the work we do please visit http://www.publichealth.lacounty.gov, visit our YouTube channel at http://www.youtube.com/lapublichealth, find us on Facebook at http://www.facebook.com/lapublichealth, or follow us on Twitter: @LAPublicHealth.