The West Nile virus has been detected in San Benito County.
“In San Benito County we just received confirmation that one sentinel chicken tested positive for the West Nile virus,” San Benito County Agricultural Commissioner Karen Overstreet said in a September 1 announcement. In response to the positive case additional traps have been deployed in the surrounding area and mosquitoes trapped will be tested for the mosquito-borne virus.
“As a preventive measure we remind the public to remove or drain any standing water and to keep current on their horses’ vaccinations,” stated Overstreet.
This is the first time since 2013 the West Nile virus has been detected in San Benito County, according to Dr. Gail Newel, a county health officer. The California Department of Public Health announced two confirmed deaths in the state due to the virus. The deceased people were residents of Kern and San Bernardino counties.
“West Nile virus can cause a deadly infection in humans and the elderly are particularly susceptible,” Newel said. “August and September are peak periods of West Nile virus transmission in the state so we urge everyone to take every possible precaution to protect themselves against mosquito bites.”
The virus is influenced by factors including climate, the number and type of birds and mosquitoes in the area and the level of West Nile virus immunity in birds. The virus is transmitted to humans and animals by the bite of an infected mosquito.
During mosquito season, which runs from mid-April into October or mid-November, depending on the weather, San Benito County Vector Control has two officers on the field. They are in charge of putting out and monitoring up to two dozen mosquito traps that are spread throughout the county.
“We are looking for the types of mosquito and a mosquito spike,” said Overstreet Wednesday morning. The breed of mosquito that carries West Nile virus is not uncommon in the county. It is called culex tarsalis.
“Our sentinel chickens are an early warning system,” explained Overstreet. “The West Nile virus does not harm the chickens. Once we have a positive on a single chicken we put out traps in that location and the surrounding area then we send the mosquitos up for testing at the Mosquito and Vector Control Association of California.”
While the tests all came back negative, Overstreet said her agency expects to get the results from a second round of tests later Wednesday.
The risk of serious illness from West Nile virus to most people is low, according to the state public health department. However, less than one percent of individuals can develop serious neurologic illnesses such as encephalitis or meningitis. People 50 years or older, as well as people with diabetes or hypertension, have a higher chance of getting sick and are more likely to develop complications.
The California Department of Public Health has reported 41 human cases of West Nile virus from nine California counties this year, as of August 22. Additionally, 203 dead birds from 29 counties and 2,040 mosquito samples from 24 counties have tested positive for West Nile virus in 2017. Those positive dead bird and mosquito samples are below last year’s numbers, but the number of positive mosquito samples exceeds the state’s most recent five-year average, according to the department.
The state department recommends that people protect against mosquito bites and West Nile virus by practicing the “three Ds:” DEET, Dawn/Dusk and Drain.
DEET: Apply insect repellent containing DEET, picaridin, oil of lemon eucalyptus or IR3535 according to label instructions. Repellents keep the mosquitoes from biting. Insect repellents should not be used on children under two months.
Dawn/Dusk: Mosquitoes tend to bite in the early morning and evening so it’s important to wear proper clothing and repellent if outside during these times. Make sure doors and windows have tight-fitting screens to keep mosquitoes out.
Drain: Mosquitoes lay eggs on standing water. Eliminate all sources of standing water by emptying flower pots, old car tires, buckets and other containers. If you know of a swimming pool that isn’t properly maintained, please contact your local mosquito and vector control agency.
The California West Nile virus website includes the latest information on virus activity across the state. People are encouraged to report dead birds on the website or by calling toll-free 1-877-WNV-BIRD (968-2473).