Officials say locals should take precautions against mosquito bites in light of lab test results that confirmed the presence of West Nile activity in Stansbury Park last week.
Scott Bradshaw, district manager for Tooele Valley Mosquito Abatement, said a mosquito trap located near the Benson Gristmill picked up adult mosquitoes that a state lab confirmed last week carried West Nile Virus.
The species of mosquito that carries and spreads the virus to humans, Culex tarsalis, is regularly active in the Tooele Valley area, but does not always carry the West Nile Virus, warranting regular tests to determine where the virus is spreading.
So far no local residents have reported any symptoms of the virus to indicate the spread of West Nile to human populations.
The timing of this year’s first confirmed West Nile activity was fairly typical for the virus, which generally spreads in the late summer, during the hottest and driest weather of the year, Bradshaw said. But the level of West Nile activity is the highest Northern Utah has seen since 2008, he said. Just this week, the state confirmed an additional 22 mosquito pools had tested positive for the virus, bringing the summer’s running total to 56 infected mosquito pools across Box Elder, Weber, Davis, Salt Lake, Utah and now Tooele counties.
But the reason for this year’s elevated activity is a mystery, Bradshaw said.
“Usually, the hot, dry seasons it [the spread of the virus] picks up,” he said. “But it hasn’t been extremely hot this year.”
One theory, he said, is that the West Nile Virus spreads according to some kind of cycle. The area had its first major outbreak of the virus start in 2003, he said, but then it died down somewhat until it began picking up in Texas again in 2012.
But it is also possible that the outbreak is linked to an unusual event last year, where some 200,000 birds died near the Great Salt Lake. Bradshaw said those birds tested positive for West Nile, and that the virus may have spread to other birds in the area — West Nile has been linked to the death of 84 bald eagles since last October, Bradshaw said.
West Nile Virus is transferred from birds to humans by the tarsalis mosquito species.
West Nile Virus is somewhat unique in that it does not affect all people equally. For roughly 80 percent of the population, Bradshaw said infection with the virus would mean little more than mild flu-like symptoms. But for the rest of the population, the virus can cause more severe symptoms, including fever, vomiting, rash, and fatigue, with symptoms lingering for up to a month. In some cases, the virus can be fatal.
Those over the age of 50 are most likely to experience severe symptoms, and most deaths attributed to the virus occur in more elderly populations, Bradshaw said. But the virus also poses a risk to those who are physically active, because of the increased amount of time athletes spend outdoors in the morning or afternoon hours.
Because there is no vaccine for West Nile, the best method of prevention is to avoid mosquito bites, Bradshaw said. Residents should wear repellents containing DEET, Picaradin, or lemon eucalyptus oil, should avoid being outside at dusk or dawn when mosquitoes are most active, and wear long sleeves and pants when outdoors. Homeowners should remove any standing bodies of water from their properties to prevent the mosquitoes, which breed in stagnant water, from moving in next door.
Bradshaw said residents are also encouraged to call mosquito abatement at 801-250-3879 to report areas where mosquitoes are present in large numbers, so that the district can keep mosquito populations at a minimum. He also indicated that residents can get more information about West Nile Virus, as well as updates on the status of the virus, on the Tooele Valley Mosquito Abatement District Facebook page.