West Nile virus-carrying mosquitoes found in East Palo Alto have prompted vector-control officials to order spraying in neighborhoods near the baylands, officials announced Thursday.
San Mateo County Mosquito and Vector Control District laboratory staff detected West Nile virus in adult mosquitoes on Thursday, according to a press release. The district will conduct truck-mounted adult mosquito control treatments in the area where the infected mosquitoes were collected. The treatment will take place between 9 p.m. Sunday, Aug. 12, and 5 a.m. Monday, Aug. 13, weather permitting.
"An adult mosquito infected with West Nile virus can pass it on to any person it bites, so we want to make sure we act quickly. It's very important that residents are aware of the risk of West Nile virus and take appropriate precautions to avoid being bitten by mosquitoes," Public Health Education and Outreach Officer Megan Sebay said in the statement.
The area to be sprayed includes parts of the Pulgas Gardens, Palo Mobile Estates and Weeks Gateway. Not all areas of the neighborhoods are included in the treatment, officials noted. The treatment area is approximately bounded by Beech Street to the north, Clarke Avenue to the west, Bayshore Road to the south and the San Francisquito Creek Trail to the east.
The county will use plant-derived insecticides or synthetic versions that include pyrethrins, Synthetic pyrethroids and piperonyl butoxide. The product currently used by the San Mateo County Mosquito and Vector Control District for adult mosquito control is called Zenivex E4. It is not harmful to humans in the very low dosages that will be sprayed or to family pets, according to the district.
County staff will collect mosquitoes after the treatment is completed. If those mosquito samples are carrying West Nile virus, the county will perform additional mosquito control treatments.
West Nile virus is transmitted through the bite of an infected mosquito. Birds are the primary hosts. Humans, horses and other animals can become infected with the disease if bitten by an infected mosquito. It cannot be spread person to person. The virus can cause a host of flu-like symptoms that are often mild. Many cases go unreported.
But the disease can become much more severe in some people, particularly those older than 60 years, according to the U.S. Centers for Disease Control and Prevention. Symptoms include fever, headache, body aches, skin rash, and swollen lymph nodes. Severe symptoms might include stiff neck, sleepiness, disorientation, coma, tremors, convulsions, and paralysis.
Dead birds are an early indication that the West Nile virus is circulating in an area. Officials ask residents to report fresh bird and squirrel carcasses to the West Nile virus hotline through westnile.ca.gov or by phone through 877-WNV-BIRD (877-968-2473).
Residents can reduce their risk of mosquito bites by taking the following precautions, according to vector control officials:
• Apply insect repellents that contain DEET, picaridin, oil of lemon eucalyptus, or IR 3535. Always follow label instructions.
• Make sure that doors and windows have tight‐fitting screens to keep out mosquitoes and repair or replace screens with tears or holes.
• Eliminate standing water and containers that can hold water from around the home.
• Wear long-sleeved shirts and long pants when outdoors.
For assistance with a mosquito problem in San Mateo County, residents can contact the district at 650-344-8592. More information on West Nile virus and district services can be found at smcmvcd.org.