The Contra Costa Mosquito and Vector Control District announced Thursday that four more dead birds have tested positive for West Nile virus. The birds were found in Walnut Creek, Brentwood, Discovery Bay and Oakley.
"This is the mosquito season that just keeps going," said the District's Public Affairs Manager Deborah Bass. "Disease transmission is still possible."
The Contra Costa Health Services reported the third human case of West Nile virus for 2012 in Contra Costa County on their website this week. The website indicates that the patient is an adult female, lives in West County and has recovered from her illness.
Since 2005, 40 people in Contra Costa County have been diagnosed with West Nile virus and in 2006, two people died from the disease. A recent study showed that the majority of cases are undiagnosed and grossly under reported. This year, a total of three people, 19 groups of mosquitoes, 66 dead birds and seven chickens tested positive for the virus. The number of infected mosquitoes, birds and chickens have surpassed the number of infected insects and animals in 2011.
The district asks all residents to still be vigilant about avoiding mosquitoes by wearing repellent when mosquitoes are present. Dumping or draining any standing water prevents mosquitoes from having a place to lay their egg, and reporting dead birds is important because they are often the first sign of West Nile virus in a particular location. Reporting neglected swimming pools is also very important because one neglected swimming pool can produce more than on million mosquitoes that can affect people up to five miles away.