California health officials said Friday that three people have died of West Nile virus this summer, marking the first deaths in what could be a particularly dangerous season for the disease.
The three people lived in Los Angeles, San Bernardino and Kern counties, according to state health officials. L.A. County health officials said the local patient who died was from the San Fernando Valley area and was hospitalized in early August.
West Nile virus is an illness that mostly exists in birds, but can be transmitted to mosquitoes that bite infected birds. Humans get the disease when they're bitten by those mosquitoes.
West Nile season typically begins with warmer weather in the summer and continues into the fall.
"West Nile virus can cause a deadly infection in humans, and the elderly are particularly susceptible," said Karen Smith, director of the state Department of Public Health. "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."
Experts say that heavy rains this winter in California have led to more mosquitoes in the region. State data show that the number of mosquitoes testing positive for West Nile is higher this year than the state's most recent five-year average.
Most people who contract the illness don't notice any symptoms. But a very small number can develop encephalitis or meningitis that can be fatal.
Last year, 19 Californians died of West Nile virus.
Health officials recommend wearing insect repellent and long pants and long-sleeve shirts outdoors, especially during dawn and dusk, when mosquitoes are most likely to be active. They also recommend draining any standing water, like in flower pots or buckets, where mosquitoes can lay their eggs.