A Butte County man became the fifth Californian to die from West Nile virus, officials reported late Monday.
They said the elderly man had been suffering from an underlying chronic disease when he became infected. Officials did not release any other information, including when he was diagnosed or when he died.
The death was the second reported in the region this year. Last week a San Joaquin County man died from the disease.
In Sacramento County, Delta breezes delayed additional local spraying again Monday evening.
During last week's spraying, a little more than 14 percent of the pesticide applied reached the ground according to one test, county officials reported.
The county's test was the first solid measure locally of how much pesticide might actually drift down to gardens, playgrounds or other gathering spots.
The results were characterized as low by county agricultural officials who ordered the testing, but higher than expected by officials of Sacramento-Yolo Mosquito and Vector Control District.
Before Monday, vector control officials had not quantified how much pesticide they expected to land, saying only that most of it should dissipate in the air.
Last week, the district took the unprecedented step of using airplanes to spray about 55,000 acres north of the American River, as rates of mosquitoes infected with West Nile virus surged.
The district had planned to spray up to 66,000 acres in southern Sacramento County starting late last week, but has repeatedly canceled the treatments because of high winds.
David Brown, manager of the mosquito district, said aerial spraying probably won't resume until the winds die down to less than 10 mph, perhaps in a day or two.
The delay makes avoiding mosquito bites that much more important as the disease outbreak mounts, Brown said.
"Mosquitoes will be active, and actively feeding," Brown said at a morning news conference.
Area residents should not be fooled by lower temperatures and high winds, he added. Mosquitoes actually live longer when temperatures drop.
A strong wind can push mosquitoes into protected areas such as backyards.
Cooler weather does have a silver lining when it comes to West Nile virus, however.
It also extends the length of time it takes for mosquito larvae to mature, giving mosquito control crews more time to kill the larvae.
Epidemic levels of mosquito infection in Sacramento County prompted the district's decision to treat urban areas with pesticide dispersed from airplanes, mosquito control and local health officials said.
But some have questioned the necessity, timing and method of the spraying.
Results from the county's pesticide testing became available late Monday.
The analysis was ordered by Juli Jensen, deputy Sacramento County agricultural commissioner, "just because of the public interest."
She said the county followed the same method it uses to investigate spraying complaints for possible enforcement action.
The state Department of Pesticide Regulation concluded that the amount found was the equivalent of about 14.5 percent of what was sprayed.
So little pesticide was released from the planes that it's important to keep the figure in perspective, said Glenn Brank, a spokesman with the Pesticide Regulation Department.
"To me, more than 80 percent staying in the air is still very little on the ground," said Jensen.
"I feel really comfortable with their application," she said.
The percentage could well be lower in neighborhoods with trees and other obstacles, she added, since the testing was deliberately done in an open area to give the county a worst-case scenario.
Samantha McCarthy, a spraying opponent, said the results from any single test are "meaningless" because wind conditions and a host of other factors can affect how much pesticide residue lands anywhere.
West Nile virus is spread most often by the bite of infected mosquitoes, which get the disease when they feed on infected birds.
Statewide, 174 West Nile cases have been reported. Sacramento County has logged the highest number of cases, with 36.
Of those infected in Sacramento County, 13 suffered effects on the nervous system such as paralysis, meningitis or encephalitis.
An additional 12 were diagnosed with West Nile fever, which can include flulike symptoms and a rash.
Ten other cases were blood donors with unknown symptoms.
In Placer County, the human West Nile toll rose Monday from three to four, with the addition of the infection of a 43-year-old woman from Roseville.
Placer health officials did not provide details about the woman's condition.
Placer County will host a public community forum at 7 p.m. Thursday in the Roseville City Council chambers to provide information about the county's mosquito control efforts.
The state Department of Health Services updates its West Nile infection numbers from throughout the state each Tuesday.
West Nile prevention tips
To reduce the risk of West Nile virus, 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. Mosquitoes can hatch in as little as a half-inch of water.
Wear long pants and long sleeves outdoors when practical.
Avoid being outside at dawn and dusk, when mosquitoes are most active. Symptoms of the virus
About 80 percent of people who get West Nile virus have no symptoms
About 19 percent get flulike symptoms that include fever, aches and fatigue.
Fewer than 1 percent will contract neuroinvasive disease, symptoms of which can include paralysis of the arms or legs, chronic headaches and chronic fatigue. For more information
To read previous coverage of the West Nile virus and to find West Nile-related links, please go to: www.sacbee.com/links
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