Mosquitoes infected with West Nile virus have spread to South San Francisco and prompted San Mateo County mosquito officials to fog in the 94080 zip code area Thursday night.
The San Mateo County Mosquito and Vector Control District collected adult mosquitoes that tested positive on Aug. 19 and will fog 1,058 acres in South San Francisco, as well as areas of Colma and Daly City between 9 p.m. Thursday and 5 a.m. Friday.
The district will use a truck-mounted fogging abatement treatment that has proven successful in San Mateo over the last few months. However, if more mosquitoes test positive after the South San Francisco treatment, it may fog the area again, according to the district.
The district will use the adulticide Zenivex, which the Environmental Protection Agency has determined is safe for urban use.
The primary hosts of West Nile are birds. Humans, squirrels, horses and other animals can contract the virus when bit by an infected mosquito, according to the district. West Nile cannot be spread person to person, according to the district.
Reports of dead birds and squirrels are an early indication the virus is circulating and resident are encouraged to report carcasses to the West Nile virus hotline at westnile.ca.gov or (877) 968-2473.
To reduce the chance of infection, residents are encouraged to drain any standing water and wear proper clothing and repellant during dawn and dusk when mosquitoes are most active, according to the district.
For more information and to see a map of Thursday’s planned fogging treatment, visit smcmad.org.