Byron has been added to the growing list of Contra Costa County locations where mosquitoes have tested positive for West Nile virus in 2018, according to the Contra Costa Mosquito & Vector Control District.
So far this year, 13 groups of mosquitoes, eight dead birds and 13 chickens from around Contra Costa County have tested positive, the district reported in a news release on Friday.
Mosquitoes with West Nile have also been found this year in Oakley, Martinez, Holland Tract, Discovery Bay and Quimby Island. Dead birds testing positive for West Nile have been found in Brentwood, Discovery Bay, Antioch and Concord.
Since 2005, 63 Contra Costa County residents have been diagnosed with West Nile. In 2006, two people died from the disease, according to the district.
In addition to warning people to wear mosquito repellant and stay indoors when mosquitoes are active at dawn and dusk, officials are reminding horse owners to get their animals vaccinated.
Since 2003, there have been more than 1,200 equine West Nile cases statewide and 534 infected horses have died or had to be euthanized, district officials said.
"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," said Steve Schultz, the district's scientific programs manager.
Residents should also dump or drain standing water to prevent mosquitoes from laying eggs.
Dead birds should be reported to the state hotline, at 1-877-968-2473.
A map of West Nile activity in Contra Costa County can be found on the district's website.
In Alameda County, 12 dead birds and 10 groups of mosquitoes have tested positive for the West Nile virus, said Erika Castillo, a spokeswoman for the Alameda County Mosquito Abatement District.