Americans are being urged to protect themselves from mosquito bites as deaths from the West Nile virus climb nationwide.
Public health authorities in Los Angeles County reported the area’s first fatality linked to West Nile virus of the year this week, alongside a broader spike in infections statewide.
The victim lived in the San Fernando Valley and was hospitalized for a neurological condition resulting from a severe case of West Nile virus, the health department said. Details about the patient’s identity were not disclosed.
The CDC has recorded more than 222 cases so far this year across 32 states, according to its West Nile webpage. At least eight deaths had been reported nationwide as of Aug. 18.
The virus, which is most commonly contracted through a mosquito bite, causes more than 130 deaths in the contiguous U.S. every year.
LA County’s announcement came as the state warned that California is experiencing its highest level of overall West Nile virus activity in five years.
Data from the California Department of Public Health shows that 30 human infections, including three fatal cases, were identified across 13 counties through Aug. 14. These figures represent an increase compared with five-year historic trends for the period.
Symptoms usually start 2–6 days after being bitten by an infected mosquito, according to the CDC.
About 20% of people who are infected develop flu-like symptoms, such as a fever with headache, body aches, joint pains, vomiting, diarrhea, or rash. Most people with mild illness due to West Nile virus recover completely, but fatigue and weakness can last for weeks or months.
Symptoms of severe illness can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness, and paralysis.
“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.”
Surveillance programs tracking sentinel chickens, horses, dead birds, and mosquito populations have detected evidence of the virus across 32 California counties.
Over 24 percent of collected dead birds carried the virus, well above the historical five-year average of 13 percent. Eight of every 1,000 sampled mosquitoes tested positive, compared to a five-year baseline of five per 1,000.
Vector control agencies operating in Los Angeles County have similarly recorded elevated levels of infected bird specimens and positive mosquito samples.
“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.
The virus spreads to humans and animals via mosquito bites. Most infected individuals are asymptomatic, though roughly one in five experience fever alongside other symptoms.
Roughly one in 150 cases develops severe symptoms, which can include high fever, muscle weakness, and a stiff neck. Health experts warned that critical complications include encephalitis, paralysis, and meningitis.
Individuals over age 50 and those with preexisting health conditions face a significantly higher risk of serious illness. Currently, no targeted treatment or vaccine exists for West Nile virus.
Americans are urged to apply insect repellent when outside, particularly during peak mosquito hours around dawn and dusk.
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