West Nile virus detected in Placer County

By: ToLewis, The Press Tribune
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A mosquito sample tested positive for West Nile virus in a rural area of Placer County west of Lincoln, officials announced Tuesday. The Placer Mosquito and Vector Control District discovered the virus in a batch of mosquitoes captured in one of many traps the district sets in different areas of the county, according to Ada Barros, spokeswoman for the district. As a result of the discovery, the Placer Mosquito and Vector Control District has increased surveillance of the area, looking for breeding sources like pools of water and checking for mosquito larvae. The district is dealing with mosquito sources by treating standing water to kill larvae and spraying the area for adult mosquitoes, Barros said. “This is a clear indication that West Nile virus activity is increasing,” said Joel Buettner, general manager of the Placer Mosquito and Vector Control District, in a statement. “We are very concerned that human transmission can happen as mosquito populations begin to increase.” Placer County had three cases of West Nile virus in humans in 2010. None have been reported so far this year. Last year, more than 30 mosquito samples tested positive for West Nile virus, most of them coming from west of Roseville, Barros said. “Usually, it’s in the agricultural areas where we find the first indications of West Nile activity,” Barros said. Barros said the district, which was recently commissioned to perform as a Biosafety Level 3 facility and conduct in-house testing in Roseville, expects to see a rise in mosquito populations due to consistent high temperatures. “This is actually the time of year when we see mosquito populations multiply really rapidly,” she said. “They may not have been noticeable one or two weeks ago, but they will be a lot more noticeable now.” Barros said the public can protect themselves by staying indoors around dawn and dusk when mosquitoes are usually out. The Placer Mosquito and Vector Control District also recommends dumping or draining standing water around homes, and wearing a mosquito repellant such as DEET. “There are other materials on the market that people can use that is CDC approved if people don’t like DEET,” Barros said. “But DEET will offer the most protection for a longer amount of time.” Toby Lewis can be reached at Follow him on Twitter @TobyLewis_RsvPT.