West Nile cases in Sacramento and the rest of the state continued rising this past week, according to tallies released Friday afternoon.
In Sacramento County, which has the highest number of reported human cases among counties in the state, the number rose from 47 to 58. Those infected range in age from 17 to 86, with the median age 57.
Statewide, the number of reported human cases rose from 208 to 265 so far this year, according to the California Department of Health Services, which posts new figures on Tuesdays and Fridays. Six people with West Nile virus have died throughout the state.
Just a month ago, Sacramento County had no reported cases in people. The rapid spread of the disease in late July and early August prompted the Sacramento-Yolo Mosquito and Vector Control District to launch a three-night aerial insecticide assault Aug. 8-10. It covered 50,000 acres in northern parts of Sacramento County.
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Aerial spraying over 66,000 acres in southern Sacramento County was grounded again Friday night by Delta winds, as it has been since Aug. 12. Ideally, the district likes winds of about 5 mph during aerial spraying to gently help distribute the pesticide. Winds above 10 mph are too strong.
An area for aerial and ground spraying was added to the district's Web site on Friday. Jennifer Benito, district spokeswoman, said planes were not able to cover the area along the Placer County line - from Elverta to Folsom - during earlier flights, and there are plans to spray it Tuesday through Thursday, winds permitting. Benito said Rancho Cordova also has been added to the list of areas due for aerial spraying.
The aerial spraying program continued to upset some citizens, with about 15 protesting on the north side of the Capitol on Friday afternoon.
Cary Chleborad, who lives in east Sacramento and makes optical assemblies such as telescopes, said he and others want the aerial spraying to stop because of health concerns about the insecticide, as well as worries that beneficial insects may be wiped out in the process.
He questioned whether the small number of deaths from West Nile warrants the drastic step of spraying by air, noting that many more people die from the flu each year.
"Yes it can kill people," Chleborad said. "But it's not the threat that has been blown out of shape."
Chleborad and others said they want the mosquito agency to focus its efforts instead on killing mosquito larvae and on other measures to keep mosquito populations down.
Dave Brown, manager of the mosquito district, said such efforts have been under way for months and the aerial approach is needed because mosquito infection rates have risen to epidemic levels.
The agency's ground trucks, which do both larval and adult mosquito spraying, cannot cover the vast areas that need to be treated, he said.
The ground trucks applied a third treatment in the Greenhaven and Pocket areas Friday night. Tests will determine if additional treatment is necessary.
The agency's ground trucks can cover about 10,000 acres in an evening, and most are occupied with larvae treatments.
With planes, the agency can cover 50,000 to 70,000 acres in a night, Brown said.
As he has every day during the aerial-spraying drama, Brown urged people to take personal measures to avoid being bitten by an infected mosquito: Eliminate standing water. Avoid being outside at dusk or dawn, and if you do go out, use repellent and wear long sleeves and long pants. Repair cracks or tears in doors and screens to keep mosquitoes out of your home.
The product being sprayed aerially is called EverGreen Crop Protection EC 60-6. It contains 6 percent pyrethrins (a killing agent extracted from chrysanthemum flowers) and 60 percent piperonyl butoxide (a "synergist" that slows an insect's ability to break down pyrethrins, and which is classified by the U.S. Environmental Protection Agency as a possible cancer-causing agent).
In addition, the product contains inert (non-active) ingredients that are designed to help dissolve and bind the active ingredients and make the product dissolve more easily in water or oil, said Jason Scott, sales support and operations manager for the insecticide's maker, McLaughlin Gormley King Co.
The inert ingredients - glycol ethers, petroleum distillates, surfactants and sorbitan monooleate - are commonly found in household soaps, dishwashing products and laundry detergents, said Ron Tjeerdema, chairman of the UC Davis Department of Environmental Toxicology.
At the low doses being applied by the mosquito agency, he and others said, the chemicals are not dangerous for people or animals.
The actual number of people infected by the West Nile virus is likely higher than the 265 reported by the state Friday because there is always a lag time between diagnoses and reports to public health officials, said Vicki Kramer, chief of the state Department of Health Services Vector Borne Disease Program.
Last year on Aug. 15, she said, the state knew of 168 cases of West Nile in people but later learned that 422 people actually were infected at that point.
Last year's cases were largely centered in Southern California.
West Nile at a glance
2005 human cases
Sacramento County: 58;
Stanislaus County: 30;
Butte County: 7;
Sutter County: 3;
San Joaquin County: 4;
Yolo County: 4;
Placer County: 5
Where to get information
To report a dead bird, call (877) 968-2473 (WNV-BIRD)
Sacramento and Yolo County residents can request mosquitofish, report untreated pools of standing water, get aerial spraying information and sign up for e-mail notification of local insecticide treatments by calling the Sacramento-Yolo Mosquito and Vector Control District at (800) 429-1022 or (916) 685-1022, or at www.fightthebite.net
Placer County residents can get West Nile information and obtain mosquitofish by calling the Placer Mosquito Abatement District at (916) 435-2140. For other information, contact the Placer County West Nile virus line at (530) 889-4001 or go to www.placermosquito.org or www.placer.ca.gov/wnv
Butte County residents can go to www.buttecountypublichealth.org or call (800) 339-2941.
Anyone with concerns about the health effects of spraying can call the California Poison Control number at (800) 876-4766.
Other helpful Web sites:
Centers for Disease Control and Prevention, www.cdc.gov;
California Department of Health Services, www.westnile.ca.gov.
Prevention tips To reduce the risk of catching West Nile, the Sacramento-Yolo Mosquito and Vector Control District recommends:
Use an effective mosquito repellent containing ingredients such as DEET, Picaridin or oil of lemon eucalyptus.
Repair tears in door and window screens.
Drain standing water.
Wear long pants and long sleeves outdoors when practical.
Avoid being outside at dawn and dusk, when mosquitoes are most active.
What's in the pesticide
Here are the ingredients to EverGreen Crop Protection EC 60-6, the pesticide that is being aerially sprayed over Sacramento County:
Active ingredients - Pyrethrins (a killing agent extracted from chrysanthemum flowers) -6 percent piperonyl butoxide (known as PBO, this "synergist" slows an insect's ability to break down pyrethrins; and is classified as a "possible" cancer-causing agent by the U.S. Environmental Protection Agency) -60 percent
Inert (non-active) ingredients - Glycol ethers (a solvent and inactive byproduct of PBO), less than 1 percent. Petroleum distillates (refined kerosene, a solvent used to dissolve the active ingredients), about 5 percent.
Remainder - A proprietary mixture designed to dissolve and bind all ingredients together. It includes ionic and anoinic surfactants (soap chemicals found in dishwashing soaps and laundry detergents; these enable the solution to be diluted in water or oil) and sorbitan monooleate (an oil emulsifier and stabilizer that allows the product to be mixed with oil for application.)
About the writer:
- The Bee's Deb Kollars can be reached at (916) 321-1090 or email@example.com.