Updated at 5:11 p.m. Friday, Sept. 21, 2012.
Three more dead birds picked up in Santa Monica have tested positive for West Nile virus, bringing the total number so far this year to five.
The birds were collected in the 90402, 90404 and 90405 zip codes, according to a Los Angeles County West Vector public health advisory dated Sept. 18.
Two birds found in Santa Monica between May and July 23 in the 90402 and 90404 zip codes had also tested positive for the virus, which is spread by mosquitoes.
When humans and other mammals, such as horses, are bitten by infected mosquitoes they can also become infected. Most will not become ill, but for the small proportion who do become sick, symptoms can include fever, headache, rash, muscle weakness, and nausea and vomiting, according to the Los Angeles County Department of Public Health.
As of Friday, in the greater Los Angeles area, 51 dead birds, 188 mosquitos and four chickens have tested positive for the virus. Los Angeles County also saw its first West Nile Virus-linked death in 2012 this week, according to vector control.
There were four fatalities in 2011.
The 3,142 West Nile virus cases reported nationwide this year through the third week in September is the highest number reported to the Centers for Disease Control and Prevention since 2003. Two-thirds of the cases have been reported from seven states, including California.
Residents who discover a dead bird should call 1-877-WNV BIRD (1-877-968-2473). Dead birds must be less than 24 hours old to be able to test them for West Nile virus. If the bird is rigid or decomposed, it cannot be used for testing.
The public is encouraged to report dead birds to help with West Nile virus surveillance and control efforts.