Warming Temperatures Set Stage for Mosquitos

Act now to prevent mosquitoes and disease risks as temperatures warm

West Nile Mosquitoes Found In West San Fernando Valley, La Mirada, Cerritos
The Greater Los Angeles County Vector Control District said Friday it has confirmed seven additional mosquito samples positive for West Nile virus. This brings the total number of samples positive for the virus within the district’s service area to 13 this year, according to a statement. The new positive samples were collected from six new areas: Winnetka, West Hills, Canoga Park, Granada Hills, La Mirada and Cerritos. West Nile virus is endemic in Los Angeles County, and the summer heat can increase virus activity and mosquito populations. So far this year, 10 human cases of West Nile Virus have been reported in California, two of which were identified by the Los Angeles County Department of Public Health. West Nile virus is transmitted to people and animals through the bite of an infected mosquito. There is no cure for West Nile virus. One in five persons infected with the virus will exhibit symptoms, which can include fever, headache, body aches, nausea, or a skin rash. These symptoms can last for several days to months. One in 150 people infected with the virus will require hospitalization. Severe symptoms include high fever, muscle weakness, neck stiffness, coma, paralysis and possibly death.

Record rainfall provided relief to drought-thirsty Southern California but created havens for disease-spreading mosquitoes in people’s yards.

Vector control officials are advising that Los Angeles County residents must take extra precautions with green, unmaintained pools, rain barrels and other small containers that have collected rain water. Since mosquitoes can complete their life cycles from egg to adult in about a week, collected water should be emptied or used within the week, rain barrels and containers must be tightly sealed to prevent mosquito entry, and green, unmaintained pools should be cleaned.

If residents need to store water in rain barrels, buckets, and other similar containers longer than a week, these steps should be taken to ensure they are mosquito-proof:

  • Cover all water-filled containers with tightly fitting lids.
  • Screen all openings such as downspouts from the roof gutters with a 1/16 inch fine mesh to keep mosquitoes out.
  • Check for holes in screens monthly to prevent mosquitoes from entering the container and laying hundreds of eggs.
  • Use and maintain natural mosquito control products containing Bti in water that must be kept for longer periods.

Take advantage of this rainfall to find and remove all unused containers from around the home that may collect water and contribute to mosquito problems. Other common sources include plant saucers, buckets, tires, pet water bowls, recycling bins, trash cans, and even trash hidden in nearby bushes.

“Mosquito eggs only need a teaspoon of water to complete their life cycle,” said Anais Medina Diaz, public information officer at the Greater Los Angeles County Vector Control District (GLACVCD). “By eliminating mosquito breeding sources in your home today, you can protect your family’s health as temperatures warm up in Southern California.”

While residents do their part to tackle the standing water left by the recent rains around their homes, vector control technicians are in the field monitoring disease activity and controlling mosquito populations throughout GLACVCD’s jurisdiction. For more information or to anonymously report green, unmaintained pools, please visit the District’s website at www.glacvcd.org.

Residents are urged to use EPA-registered repellents when spending time outdoors to prevent mosquito bites and WNV illness. Not all repellents are effective against mosquitoes but the Centers for Disease Control and Prevention recommends repellents with the following active ingredients: DEET®, Picaridin, IR3535 and Oil of Lemon Eucalyptus.

West Nile virus is endemic in Los Angeles County, and the summer heat can increase virus activity and mosquito populations. So far this year, 10 WNV human cases have been reported in California, two of which were identified by the Los Angeles County Department of Public Health. Visit CalSurv Maps for a comprehensive look at this year’s West Nile virus activity throughout Southern California.

The District works year-round to actively search for and manage water-holding areas such as gutters, ditches, storm drain channels, basins, and non-functional pools and ponds, but there are many more mosquito breeding sites on private property that require the public’s attention. Mosquito control is a shared responsibility and the District needs the help of the community to eliminate water-holding containers to reduce mosquito populations.

About West Nile virus:
According to the Los Angeles County Department of Public Health, West Nile virus is a leading cause of severe infections of the nervous system among adults older than age 50 in Los Angeles County.

WNV is transmitted to people and animals through the bite of an infected mosquito. There is no cure for WNV. One in five persons infected with the virus will exhibit symptoms.  Symptoms can include fever, headache, body aches, nausea, or a skin rash. These symptoms can last for several days to months. One in 150 people infected with the virus will require hospitalization. Severe symptoms include high fever, muscle weakness, neck stiffness, coma, paralysis, and possibly death.

About GLACVCD
The Greater Los Angeles County Vector Control District is a public health service agency formed under the authority of the California State Health & Safety Code. Our mission is to reduce populations of public health vectors below nuisance levels and prevent human infection associated with mosquito-transmitted diseases.