A Kern County resident has been infected with West Nile virus, the first human to have reported contracting the disease in the county, according to the Kern County Public Health Services Department.
West Nile virus, an arthropod-borne virus, is transmitted through mosquitos, which contract the virus through birds they feed on.
The most recent infection could be the first of many, as a historic water year has filled up once-dry aquifers, banks and basins — all breeding grounds for the culex mosquitos that carry the disease and transmit it when they bite humans, said Gene Abbott, Kern Mosquito and Vector Control Superintendent said.
“The threat is going to be larger this year,” Abbott said. “We have 10,000 to 15,000 more surface acres of water than a normal year — places where mosquitoes can breed.”
The infection makes Kern one of three counties across the state to have a reported human infection, according to the California Department of Public Health. The other two are Kings and Los Angeles counties, which recorded one human case each.
“This is the first reported human case of West Nile virus this season,” said Matt Constantine, director of Kern County Public Health Services. “Kern residents should take precautions to prevent being bitten by mosquitoes, particularly during summer, which is the most risky time of year for mosquito-borne illness.”
Kern County saw 17 reported human cases last year, and 11 in 2015, according to state records. The last West Nile virus-related death here was 2015.
The risk of serious illness to most people is low, public health officials said.
About 80 percent of those infected are asymptomatic but others develop headaches, body aches, vomiting, diarrhea or a rash, said Kern County Public Health spokeswoman Michelle Corson.
Fewer than 1 percent of individuals infected can develop a serious neurologic illness such as encephalitis or meningitis.
People over the age of 60 are at greatest risk of getting sick and are more likely to develop serious symptoms when infected with West Nile virus. Individuals with certain medical conditions, such as cancer, diabetes, hypertension, kidney disease and people who have received organ transplants are also at greater risk for developing severe symptoms and illness.
The local resident who was infected lives in the 93203 ZIP code, which spans from Arvin south to the Grapevine, according to the health department. It’s unknown, however, if he was bit by a mosquito in that area, or elsewhere.
Either way, there are no West Nile virus hot spots around the county where the incidence is higher than others, Corson said.
“They’re attracted to wet, shady places, so you could be more concerned around those areas, but you can be bitten anywhere,” Abbott said, pointing to the City of Bakersfield’s 2,800 acres and surrounding water banks near the Kern River Parkway Trail, many of which are endangered species areas. That means vector control can do little in the way of abatement, Abbott said.
Just about every area where Kern Mosquito and Vector Control sets traps for mosquitoes captured ones that tested positive for West Nile virus, Abbott said. So far it has recorded 19 mosquitoes that tested positive for the virus, according to the CDPH.
“Mosquitoes fly and birds fly, so I think if the mosquito has everything it needs — standing water and animals to feed on — it doesn’t need to travel too far,” Abbott said.
He stressed, however, that preventing the transmission of the disease starts with clearing residential areas of standing water to reduce breeding grounds.