Drought Makes California A Breeding Ground For West Nile Virus

Experts say the threat of West Nile virus has been increased by drought in California, where one person has already died of the illness this year.

Last year saw a surge in West Nile deaths in California, according to the Los Angeles Times. California officials said there were over 800 cases of West Nile in the state last year. That’s the highest number since 2003, when the virus first hit California. Over 561 patients developed neurological problems from the disease, a serious consequence that can swell the brain.

This year, as of July 17, at least “33 California counties have reported instances of West Nile activity in birds and insects - four more counties than this time last year and above the five-year average of 22 counties,” The Sacramento Bee reported.

California’s historic drought appears to be helping the virus flourish. Dry weather has thrown a wrench into the ecosystem, which would not normally be so inhabitable for the virus. The Los Angeles Times reported:

With fewer sources of water for birds and mosquitoes, they're coming into closer contact with humans in their search for water, increasing the chance of transmission. Health officials recommend using insect repellent to stave off mosquitoes and wearing protective clothing during dawn and dusk, when the insects are most active. They also recommend emptying things such as flower pots or buckets because mosquitoes lay eggs in standing water.

Karen Smith, director and state health officer of the California Department of Public Health, explained the correlation between the virus and drought, per the Times.

“As birds and mosquitoes sought water, they came into closer contact and amplified the virus, particularly in urban areas,"she said, per the report. "The lack of water could have caused some sources of water to stagnate, making the water sources more attractive for mosquitoes to lay eggs.”

Officials confirmed that the year’s first known virus death in California occurred in July. “The death of a senior citizen in Nevada County comes in a year with an unusually high number of cases of West Nile among mosquitoes and birds, officials said. Infected mosquitoes transmit the virus to humans and animals, mostly birds,” the Los Angeles Times reported.

Smith commented on the recent death in a statement.

“This death is a tragic reminder of how severe West Nile virus disease can be,” Smith said. “West Nile virus activity is more widespread in 2015 than in years past. Californians need to be vigilant in protecting themselves.”

More drought stories can be found at Water Online’s Water Scarcity Solutions Center.