Standing water to make for a doozie of a mosquito season

By Stephen Ward

With summer approaching, residents and vacationers are beginning to flock to the lake and its resorts, basking in the sun and enjoying the season.

Unfortunately, they’re not the only ones who love the warm weather; mosquitoes are starting to pervade the Lake Tahoe region, and counties are stepping up their defense to ensure this mosquito season isn’t a nasty one.

Tahoe's other season -- mosquito season is about to arrive.

Ada Barros, public information officer for Placer County’s Vector Control District, said Tahoe’s wet winter might result in this mosquito season being worse than in previous years.

“When the water pools earlier, that gives (mosquitoes) more habitat to develop,” Barros said.

Barros’ district covers the Truckee, Kings Beach and Tahoe City, as well as the northwest region of the lake.

Karen Bender, supervising environmental health specialist for El Dorado County Environmental Management, agreed with Barros, saying this summer is susceptible to an influx of mosquitoes.

“(El Dorado County) is expecting this season to be heavy with mosquitoes due to the large amount of moisture in the basin over the winter and into spring,” Bender said.

County officials aren’t the only ones predicting an escalated mosquito season. Gary Barbato, hydrologist for the National Weather Service, said this past winter created a lot of stagnant water in the area through snowmelt.

“Whenever there’s a lot of snowmelt, you’re going to have more ponding, and more mosquito activity,” Barbato said. “From what I know about water, that’s primary mosquito breeding ground.”

Barbato, in fact, does know quite a bit about water. He received a master’s degree in water resources from the University of Wyoming and has worked for the NWS for 30 years. He said the high water mark for runoff, an indicator of when the mosquito season will be at its apex, is estimated to be about June 6.

In order to prevent large mosquito infestations in the region, El Dorado County technicians check breeding sources and treated areas where mosquito larvae are found, Bender said. Some areas, such as Trout Creek, are not accessible for monitoring since logging activities are taking place, Bender said.

Barros said her group sprays two types of insecticides across Placer County, larvicide and adulticide. Larvicide is sprayed primarily in water and is used to kill premature mosquitoes, while adulticide is used to prevent mosquitoes capable of flight. Barros said her group has never needed to spray adulticide in the Tahoe region.

As well as spraying, Barros’ group tests dead birds for West Nile virus and has a sentinel chicken coop that it takes blood samples from regularly.

No cases of the West Nile Virus were discovered in humans last year in the Tahoe area, however three cases were found in the foothills of Placer County.

“A lot of folks don’t realize there are different types of mosquitoes,” Barros said. “Although there are some right now in the foothills, they’re not necessarily the ones that carry disease.”

Brooks Martin, a physician who specializes in family practice at Barton Family Medicine, said West Nile Virus symptoms are difficult to pinpoint, but no cases of the virus were discovered in his office last year.

“Unless people come in with meningitis-like symptoms, we generally don’t believe West Nile virus is the cause,” Martin, who has been practicing medicine in the area for more than 20 years, said.

Bender said no cases of West Nile virus occurred last year in her group’s area of the Tahoe basin, but warned that dogs and other pets can be exposed to West Nile in the same way humans can. Animals are resistant to the virus and rarely become ill, she said.

As for what people can do to prevent mosquito bites, Bender suggested eliminating all sources of standing water that can support mosquito breeding, including old tires and kids’ play toys. Another tip Bender said is to use insect repellent containing DEET.

Barros’ group advises people to exercise the three “D’s” — drain standing water, defend with repellent and long-sleeved clothing, and to call her district with any questions.