Contra Costa Mosquito & Vector Control

FOR IMMEDIATE RELEASE     -     October 3, 2014

Contact: Deborah Bass
               Public Affairs Mgr.

(925) 771-6112 - office
(925) 260-4670 - mobile 

For human cases, please contact Contra Costa Health Services at 888-959-9911


 Previous rain and current heat help mosquitoes to thrive


CONCORD, CALIFORNIA - - The Contra Costa Mosquito & Vector Control District is reporting increased mosquito populations most likely due to last week's rain and this week's warmer temperatures. Mosquitoes reproduce faster and their populations increase exponentially in hotter weather. Until now mosquito populations had been well below average, but with unusually high infection rates.


"Mosquitoes are enjoying their last hurrah," said Steve Schutz, Ph.D., scientific program manager for the District. "The little bit of rain coupled with the heat make perfect conditions for mosquitoes to thrive."

West Nile virus activity continues in Contra Costa County. The District reports today that a group of mosquitoes from Byron tested positive for West Nile virus as well as one chicken from Holland Tract and three dead birds from Danville, Discovery Bay and Martinez. All 2014 West Nile virus activity can be found on the District's website.

According to the California West Nile Virus website, so far this year compared to the same time last year there are 425 human cases compared to 205 last year, 2195 dead birds compared to 1144 last year, 3047 mosquito samples compared to 2379 last year, and 361 chickens compared to 404 last year . 


Residents are urged to help reduce their risk of contracting mosquito-borne diseases by following these guidelines: 

  • Dump or drain standing water. Mosquitoes can't begin their lives without water.
  • Defend yourself against mosquitoes by using repellents containing DEET, Picaridin, or Oil of Lemon Eucalyptus.
  • Avoid being outdoors when mosquitoes are present, typically dawn and dusk.
  • Report neglected swimming pools by calling 925-771-6195 or visiting  Anonymous calls accepted. Just one neglected pool can produce more than 1 million mosquitoes and affect people up to five miles away. 
  • Report dead birds to the state hotline: 1-877-968-2473. All reports are crucial, even if the bird does not meet criteria for testing.

Since 2005, 49 people in Contra Costa County have been diagnosed with West Nile virus. In 2006, two people died from the disease. Recent studies have shown that the majority of cases are not diagnosed and are grossly underreported. For 2014, a total of 22 groups of mosquitoes, 14 chickens and 42 dead birds have tested positive for the virus.  


Visit the District's website or click on these links for current West Nile virus activity  or to receive automatic emails for when the District fogs for adult mosquitoes.


Contra Costa Mosquito & Vector Control District, an independent special district and public health agency, is located at 155 Mason Circle in Concord. Call the District to report mosquito problems at (925) 771-6195 or visit their office between 8:00 a.m. and 4:30 p.m. to get FREE mosquitofish for ornamental ponds, horse troughs or neglected swimming pools.    


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