The Stanislaus County Health Services Agency has reported 24 human cases of the ailment in Stanislaus County so far this year. Those include three neuroinvasive cases in the 95363 zip code that affected male patients ages 41, 49 and 66, according to Trudi Prevette, a communicable disease nurse for the county health services agency.
West Nile virus is most commonly transmitted to humans and animals through mosquito bites. The risk of serious illness to most people is low. However, some individuals — less than 1 percent — will develop serious neurological illness, such as encephalitis or meningitis.
People age 50 and older are more likely to fall ill and more likely to develop serious symptoms following infection with West Nile virus. However, Prevette noted that people of various ages contracted the virus within Stanislaus County this year, including several middle-aged residents.
West Nile figures up in 2012
As of Wednesday, Oct. 31, the county had confirmed 14 of the 24 reported cases as neuroinvasive cases of West Nile, Prevette said. The other 10 reports were confirmed as the less dangerous form of the ailment, known as West Nile fever, which causes flu-like symptoms.
Six neuroinvasive cases and four West Nile fever cases were confirmed in Stanislaus County in 2011, Prevette said.
Fifteen people throughout the state died from the virus this year, up from nine deaths in 2011, though no deaths connected to West Nile were reported in Stanislaus County this year.
The number of dead birds and mosquito samples found to be infected with the virus nearly doubled compared with the year before, said David Heft, general manager of the Turlock abatement district, which covers Stanislaus County’s West Side.
“It was pretty bad nationwide,” Heft said. “I think scientists have been working for awhile, trying to find out what the commonality was and why (these cases) were over such a large geographic area.”
Trouble at the treatment plant
Two of the cases in the county were reported east of city limits in rural Patterson, according to Heft.
He noted that those cases and a case east of Ceres were all close to the secondary Modesto Secondary Wastewater Facility, where the Turlock Mosquito Abatement District has reported problems with West Nile virus. All three cases resulted in hospitalization, Heft said.
The Jennings Road wastewater treatment pond is about two miles away from northeastern portions of rural Patterson, according to a distance mapping application from DaftLogic.com.
Heft said that the vegetation that grows on the wastewater ponds, such as tule, helps by removing nitrogen from the water, but it also harbors mosquitoes and protects their larvae from mosquito-eating fish.
Effluent from tomato canneries that ends up in wastewater ponds also attracts the virus-carrying pests, Heft said.
The mosquito abatement district found West Nile virus in fewer samples from Patterson’s wastewater treatment pond on Poplar Avenue than from the Jennings Road facility, he said.
The area surrounding Grayson about six miles north of Patterson, right next to the San Joaquin River, is also a hotspot for mosquito breeding. However, Heft said there was not an unusually high amount of West Nile activity in that area this year.
Heft noted that the harvest season in the late summer and early fall months of August, September and October can be a particularly bad time for mosquitoes, as they move away from cornfields into more populated areas after the corn is chopped down.
As a result, he urged people to take precautions, such as wearing repellent and wearing pants and long-sleeved clothing during the dusk and dawn hours.
“Most people with West Nile virus don’t even remember getting bit by a mosquito,” Heft said.
The mosquito abatement district also encourages people to report dead birds, as they are more likely to be stricken with the disease than people and can give officials a better idea of where West Nile virus is present.
As of Oct. 25, 51 birds were found with the disease in Stanislaus County, and 210 mosquito samples were found with the virus countywide, according to the California Department of Public Health.
People can take the following steps to protect themselves and others from mosquito bites and West Nile virus:
• Apply insect repellent containing DEET, oil of lemon eucalyptus or Picaridin when outdoors, according to label instructions.
• Dump or drain sources of standing water. During warm weather, mosquitoes can breed within four days.
• Change the water in pet dishes often and regularly replace water in birdbaths. Drill holes in tire swings so water can drain.
• Avoid spending time outside when mosquitoes are most active, at dawn and dusk, and especially during the first two hours after sunset.
• When outdoors, wear long pants, long-sleeved shirts and other protective clothing when possible.
• Keep mosquitoes out of homes with tight-fitting screens on doors and windows.
Residents can call their local mosquito abatement districts to report a neglected swimming pools or ornamental ponds or to discuss questions or concerns. West Side residents should call the Turlock Mosquito Abatement District at 634-1234.
Horse owners are urged to consult their veterinarians about proper and timely WNV vaccinations.
Individuals can report dead birds to the California Department of Health Services online at www.westnile.ca.gov/report_wnv.php or by calling 877-968-2473.
Recorded information in English and Spanish is available from the West Nile virus hotline at 558-8425. More information is online at www.www.westnile.ca.gov and www.stanemergency.com.
• Contact Jonathan Partridge at 892-6187, ext. 26, or firstname.lastname@example.org.