Two sentinel chickens used to detect West Nile Virus in Colusa County tested positive last week for the virus, and the California Department of Public Health has confirmed that four people have now died in California due to the disease. The victims were residents of Glenn, Yuba, Yolo, and Placer counties.
“We have no human or bird cases of West Nile Virus yet,” said David Whitesell, manager of the Colusa County Mosquito Abatement District. “But if the chickens test positive, it means that it is here.”
The presence of West Nile Virus is not unusual for this time of year, as the virus is transmitted to humans and animals through the bite of an infected mosquito.
As of Friday, the CDPH reported 79 people have tested positive for West Nile Virus in 37 counties in 2018, and of the 79 cases, 55 percent have a more serious form of the disease, which can result in long-term illness or death to people with compromised immune systems and the elderly.
People 60 years of age and older and individuals with diabetes or hypertension have a higher chance of getting sick, and are more likely to develop complications, the CDC said. Most people with the disease, however, will not know they have it because it causes mild symptoms or none at all.
In addition to the number of humans who have tested positive for the disease, 430 dead birds from 18 counties have tested positive for WNV in 2018, up from 337 for the same time period last year, and 1,730 mosquito samples from 28 counties have also tested positive for WNV this year.
Although the number of human cases is down from 143 for the same time period last year, health officials said people should remain vigilant and avoid getting bit by mosquitoes.
“We are still in a peak period of West Nile virus transmission in the state so we urge everyone to take every possible precaution to protect themselves against mosquito bites,” said CDPH Director and State Health Officer Dr. Karen Smith, in a statement.
Whitesell said the Colusa County Mosquito Abatement District has been actively spraying for mosquitoes, but residents can expect to see the pests through the first week in November.
“When you have rice, duck clubs, and wetlands, then you have a long season,” Whitesell said.
Throughout the mosquito season, Whitesell urges residents to wear protective clothing or use mosquito repellent containing DEET, picaridin, or oil of lemon eucalyptus, make sure you have tight fitting screens, and eliminate all sources of standing water around your home.
The district will continue spaying in the Colusa area. Williams will have just one more aerial application, Whitesell said.
West Nile Virus first appeared in California in 2003 and by 2004, WNV had spread to all 58 counties. ■