Los Angeles County health officials were urging residents Friday to take precautions against mosquito bites following confirmation of the county’s first West Nile virus death of the year amid elevated virus activity statewide.
The person who died was a San Fernando Valley resident who was hospitalized with neurological illness caused by severe West Nile virus, according to the Los Angeles County Department of Public Health. No additional information about the resident was released.
Fifteen West Nile virus infections have been documented in Los Angeles County so far this year, excluding Long Beach and Pasadena, which have their own health departments. County officials said the number of infections is above the five-year average for this point in the season.
Half of the people infected in the county this year live in the San Fernando Valley, according to the county.
“We extend our heartfelt condolences to the family and friends grieving the loss of a loved one due to West Nile virus,” Los Angeles County Health Officer Dr. Muntu Davis said. “This tragic loss is a reminder of the serious threat posed by mosquito-borne diseases, including West Nile virus and dengue.”
Davis urged residents to use insect repellent, eliminate standing water where mosquitoes can breed and make sure windows and doors have tight-fitting screens without holes or tears.
The county announcement came the same day the California Department of Public Health reported that West Nile virus activity statewide has reached its highest level in five years.
As of Aug. 14, 30 human cases of West Nile virus, including three deaths, had been reported in 13 California counties this year, according to the California Department of Public Health. The number of human cases is above the five-year average for this point in the year.
“West Nile virus can be fatal, particularly for the elderly and immunocompromised,” said CDPH Director and State Health Officer Dr. Erica Pan. “August and September are peak periods of West Nile virus transmission in the state, so we urge everyone to take precautions to protect themselves against mosquito bites.”
Signs of West Nile virus activity have been detected in 32 California counties through surveillance of mosquitoes, dead birds, sentinel chickens and horses, according to CDPH.
More than 24% of dead birds identified through surveillance have tested positive for the virus, compared with a five-year average of 13%. Eight out of every 1,000 mosquitoes tested are positive, compared with a five-year average of five per 1,000, state officials said.
Los Angeles County vector control districts have also reported a higher-than-expected number of positive mosquito pools and dead birds this year.
“After experiencing the warmest winter on record, West Nile virus amplification and consequently detection in Los Angeles County started almost two months early this year, leading to widespread activity countywide,” said Susanne Kluh, general manager of the Greater Los Angeles County Vector Control District.
Kluh said virus detections remain frequent despite suppressed mosquito abundance and urged residents to wear repellent when outdoors, particularly around dawn and dusk.
West Nile virus is transmitted to people and animals through the bite of an infected mosquito. Most people who become infected have no symptoms, while about one in five develop a fever and other symptoms, according to health officials.
About one in 150 infected people develop severe symptoms that can include high fever, stiff neck and muscle weakness. Severe illness can include meningitis, encephalitis and paralysis, health officials said.
People older than 50 and those with certain health conditions face a greater risk of serious illness.
There is no vaccine or specific treatment for West Nile virus.