CONCORD, CALIFORNIA - The Contra Costa Mosquito & Vector Control District is reporting mosquitoes from Brentwood, Discovery Bay and Byron have tested positive for West Nile virus. This is the first West Nile virus activity of the year in  Byron.  

So far this year, 13 groups of mosquitoes, eight dead birds, and 13 chickens  from Contra Costa County have tested positive for the virus.  

According to the District's Scientific Programs Manager Steve Schutz, Ph.D., "This time of the year typically marks the peak of West Nile virus season, and so it is very important that citizens prevent mosquito bites by wearing repellent and horse owners should make sure their horses have had the recommended vaccinations to reduce the risk of equine cases of West Nile virus." 

Horses are susceptible to West Nile virus. The American Association of Equine Practitioners recommends horse owners consult their veterinarian about the equine vaccination to prevent West Nile virus. Unvaccinated horses can become infected by a mosquito bite and experience fever, paralysis, seizures and neurological symptoms. Since 2003, there have been more than 1,200 equine West Nile virus cases statewide; 534 infected horses have died or had to be euthanized.

To prevent mosquito bites, Contra Costa County residents should:

• Wear mosquito repellent when outside. Repellents containing DEET, Picaridin, or Oil of Lemon Eucalyptus are most effective and are recommended by the Centers for Disease Control and Prevention (CDC).
• Stay indoors when mosquitoes can be present. Mosquitoes that can transmit West Nile virus are active at dawn and dusk.

To further reduce the risk of contracting West Nile virus and other mosquito-borne diseases:

• Dump or drain standing water to prevent mosquitoes. Most mosquitoes can't start their lives without water.
• Report dead birds to the state hotline: 1-877-968-2473. Birds are often the first sign of disease transmission in a particular area. Ravens, jays, crows, and magpies can be susceptible to the virus, and may die if infected. 

Even if the birds are not tested, the reports alone yield crucial information to protect public health.

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For a list of Contra Costa County's  2018 West Nile virus activity and locations, visit the  District's website . 

Since 2005, 63 Contra Costa County residents have been diagnosed with West Nile virus. In 200 6, two people died from the disease. For current human case information, please contact Contra Costa Health Services at 888-959-9911.

Contra Costa Mosquito & Vector Control District, an independent special district and public health agency, is located at 155 Mason Circle in Concord. Contact the District to report mosquito problems online or at (925) 685-9301. Visit the office between 8:00 a.m. and 4:30 p.m. to get FREE mosquitofish for ornamental ponds, horse troughs or neglected swimming pools.