Environment

County Begins Annual Larvicide Drops to Fight West Nile virus

Working to protect the region from mosquito-spread diseases such as West Nile virus, the County of San Diego began its annual aerial drops of larvicide Wednesday on wetlands around the county.

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Working to protect the region from mosquito-spread diseases such as West Nile virus, the County of San Diego began its annual aerial drops of larvicide Wednesday on wetlands around the county.

The County started using a helicopter to precision-drop batches of solid, cereal-sized larvicide on local waterways during mosquito season when West Nile virus was first detected in the County nearly a decade ago.

San Diego County has not had a human case of West Nile virus in the last two years. Statewide, there were 158 human West Nile virus cases and nine deaths in 2011.

The County uses a larvicide that is specifically designed to target and kill mosquito larvae before they can become adult mosquitoes that are capable of spreading West Nile virus or other diseases including types of encephalitis and malaria. The larvicide contains a bacterium that human and animals can harmlessly digest, but mosquitoes cannot.

Roughly once a month during mosquito season, from May through October, the County-commissioned helicopter applies the larvicide to about 920 acres of waterways — roughly 43 ponds, rivers and wetlands — around the county.

In addition to the monthly larvicide drops, the County of San Diego Department of Environmental Health has given out free mosquito-eating fish to local residents, worked with the Sheriff’s department to find neglected pools that can become mosquito-breeding grounds, and conducted public information campaigns on the Internet, television, in schools and at health fairs to tell people how they can evade contamination.

County officials urge the public to help protect themselves by remembering and acting upon the phrase, “Prevent, Protect, Report.

  • Protect Yourself from Mosquito Bites: Protect yourself from the virus by staying inside when mosquitoes are most active, between dusk can dawn. Wear long sleeves and pants when outdoors. Make sure Screens on windows and doors are in good condition and secured.
  • Prevent Mosquito Breeding: Dump out or remove any backyard item that can hold water, such a plant saucers, rain gutters, buckets, garbage cans, toys, old tires and wheelbarrows. Mosquito fish may be used to control mosquito breeding in backyard water sources such as unused swimming pools, ponds, fountains and horse troughs.
  • Report Dead Birds and Green Swimming Pools: Please report dead crows, ravens jays, hawks and owls and green pools to the Vector Control Program.

County officials said people can sign up to receive texted health-alert about vector-borne diseases including West Nile virus, hantavirus and plague over their cell phones by texting the word PEST to the number 75309.

West Nile virus is a potentially-deadly disease that is typically is carried by birds, and spread to humans by mosquitoes that first feed on the infected birds and then on people. The disease originated in Africa, then first detected in the U.S. on the East Coast in 1999 before eventually spreading to California in 2003.

For more information go to http://www.sdfightthebite.com.

Gig Conaughton is a communications specialist with the County of San Diego Communications Office. Contact