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Aerial Search for Neglected Swimming Pools Continues in North Santa Clara County


SANTA CLARA COUNTY, CALIF. - Weather permitting, the Santa Clara County Vector Control District (SCCVCD) will conduct its third and last aerial survey of the season over urban areas in Milpitas, North San José, Santa Clara, Sunnyvale, Mountain View, Los Altos, Los Altos Hill, and Palo Alto on Friday, August 13. This operation will cover approximately 100 square miles to detect neglected swimming pools and other possible sources that could harbor mosquitoes. With this survey, the SCCVCD is completing its 2010 surveillance campaign covering the majority of the Silicon Valley.

“Despite the lower than average temperatures observed during this summer, the West Nile Virus (WNV) season is still active. Statewide, the number of mosquito samples positive for WNV and the number of human cases are ahead of last year´s figures,” said Russ Parman, Acting SCCVCD Manager. To date, the SCCVCD has confirmed 23 WNV positive dead birds and ten positive mosquito samples in the County.

On August 13, a survey plane will fly at an altitude of 5,000 feet taking aerial photos. The SCCVCD will review the resulting pictures and determine which pools or other mosquito breeding sources need immediate attention. SCCVCD Technicians will then contact the pool owners to arrange for the pools to be checked and treated if they are developing mosquitoes.

Prior surveys conducted in May and June over the southern half of the valley identified over 750 newly identified green or half-empty swimming pools. Following those surveys, SCCVCD staff conducted over 1000 inspections, about 25 percent of which required immediate treatment to eliminate active mosquito breeding.

Response to the aerial survey program has been encouraging. SCCVCD Technicians who contacted and explained to property owners the health risks posed by poorly maintained swimming pools have noted that most owners take immediate steps to resolve the problem. Consequently, formal legal abatement is seldom necessary.

Transmitted by mosquito bites, West Nile Virus (WNV) causes mild to severe flu-like symptoms such as fever, headache, body ache, and, in severe cases, significant neurological damage or even death. People over 50 and those with high blood pressure are at higher risk for severe disease.. In 2009, California reported 129 WNV infections, with 112 symptomatic cases and 4 fatalities. A single poorly maintained pool in the backyard can produce millions of mosquitoes.

It is important for all residents to take the following measures to prevent mosquito bites and WNV:

At home:

  • DRAIN or DUMP standing water weekly since this is where mosquitoes lay eggs. Check items such as flowerpots and planter bases, toys, cans, leaky water faucets and sprinklers, rain gutters, buckets, pools, ponds, and old tires.
  • Make sure your DOORS and windows have tight-fitting screens.


  • Limit activities during DUSK & DAWN to prevent mosquito bites. Those are the times when the mosquitoes that transmit WNV are most active.

If you need to go outside at dusk or dawn, or when in an area where mosquitoes are active:

  • Apply insect repellent containing D.E.E.T., Picaridin, or Oil of Lemon Eucalyptus (p-menthane diol), following label instructions.
  • DRESS in long sleeve shirts and long pants, preferably of light colors.

Dead birds may indicate the presence of West Nile Virus. The SCCVCD asks Santa Clara County residents to report if they find crows, jays, sparrows, finches, or birds of prey that have been dead for less than 48 hours and do not appear to have died because of an injury, calling to the State of California WNV hotline at 877-WNV-BIRD or at

If bothered by mosquitoes or knowing of any potential mosquito-breeding source, residents can contact the Santa Clara County Vector Control District office for a free inspection by calling (408) 918-4770 / (800) 675-1155 or online at

To hear updates and general advice about WNV in Santa Clara County, residents can call (888) SCC-WNV1.

map of aerial search for neglected swimming pools in North Santa clara County

Media Contact: Russ Parman,408-593-6176 English; José Colomé, 408-210-5774 English and Spanish
Posted: August 12, 2010