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Not only can mosquitoes be often annoying pests, they can also be carriers of the sometimes dangerous West Nile Virus. Area experts say the summer months bring a conducive climate for mosquito breeding, but there are simple measures the public can take in order to reduce the risk of getting bit by the pesky insects.
Tuolumne County Public Health Official Dr. Todd Stolp said July is the month when the breed of mosquito most notorious for carrying West Nile Virus, the culex tarsalis, becomes most prominent in the Sierra foothills. The reason culex tarsalis is the most common carrier of the virus is because it feeds on both humans and birds, Stolp said. Mosquitoes pass West Nile from birds to other animals, including horses, chickens, squirrels and humans. Cases of the virus are most frequent during the late spring and early summer months when mosquitoes are out in force. Stolp said humans are often affected by mosquito bites differently depending on their immune system. Non-West Nile carrying mosquito bites can cause more severe swelling or irritation in certain people, he said. The same can be said for the virus itself, according to Stolp, because most people who contract West Nile don’t have any symptoms. People over the age of 50 or with chronic illnesses such as kidney or heart disease are more likely to feel the effects of West Nile, Stolp said. West Nile usually causes a fever lasting more than two weeks, but people at a higher risk can also develop problems such as neuroinvasive disease, encephalitis, and meningitis that can lead to convulsions and even death. There is no known treatment or cure for the virus. There have been few to no cases of West Nile reported in Tuolumne County since 2005, when 59 birds, three horses and at least one person were infected with the virus. That year was also a peak for Calaveras County, where two people, six horses and 10 people were infected. There have been no reported cases in either county this year. Only one mosquito sample and four dead birds have tested positive throughout the state so far. Public health officials say they typically see mosquito concerns grow as the summer wears on and acknowledge this past winter’s unusual weather might worsen problems. “There are lots of interesting things that modify insect populations and we aren’t really clear on what all those things are,” Stolp said. “Because of this being an unusual weather season, I think we can expect an unusual mosquito pattern, but we don’t know which way that will go yet.” Calaveras County Public Health Officer Dr. Dean Kelaita said residents of Valley Springs, Burson and Copperopolis should be especially aware of the dangers of West Nile because mosquitoes are generally more prevalent in flatter areas. “We’ve had a couple cases over the years, so it’s established in the area,” he said. “It’s a legitimate concern for people and they should be proactive in taking the steps necessary for reducing mosquito bites.” Kelaita said health departments typically advise the public of the “four D’s” to reducing the chance for bites, which includes: • Draining standing water from around their homes, which can include removing old tires, kids toys and empty pots that can collect water during rains. • Don’t go out at dawn and dusk when mosquito activity is generally at its peak. • Dress in long pants and a long shirt when outdoors, especially at dawn or dusk. • DEET, the active ingredient in most insect repellents, which people are encouraged to apply before traveling outdoors. |