Five mosquito pools tested positive for West Nile virus in the Tooele Valley Mosquito Abatement District during the past two weeks, according to district manager Scott Bradshaw.
Utah State Public Health Laboratory notified Bradshaw on Monday that three samples collected on Aug. 13 in the Benson Gristmill area tested positive for the virus.
“We trapped over 300 mosquitoes on the night of Aug. 13 and three pools tested positive for West Nile virus,” Bradshaw said. A pool of mosquitoes contains anywhere from 10 to 100 mosquitoes, he said.
Also, Bradshaw said two mosquito pools tested positive for West Nile virus from samples taken on Aug. 6. One pool was near the Walmart Distribution Center in Grantsville and the other near Ritchie Brothers in Lake Point.
“We like to notify the public of areas where the virus has been detected so they can dress appropriately when in those areas,” Bradshaw said. “They should wear long-sleeved shirts and long pants. Mosquito repellant with DEET or Picaridin is also a great way to avoid mosquito bites.”
He said 80 percent of people infected with West Nile virus do not develop any symptoms.
About one-in-five infected with the virus develop a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea or a rash, according to the U.S. Centers for Disease Control and Prevention.
Most people with West Nile virus disease recover completely, but fatigue and weakness can last for weeks or months, according to the CDC.
One-in-150 who are infected develop a severe illness affecting the central nervous system, according to CDC.
Bradshaw said anyone who is bitten by an infected mosquito can get the disease.
“People over the age of 60, people with certain medical conditions, such as cancer, diabetes, hypertension, kidney disease, and people with poor immune systems are more likely to develop a serious illness if infected,” he said.
“Everyone should participate in mosquito prevention and protect themselves from bites,” Bradshaw said. “Residents can remove unnecessary standing water from flower pots, gutters, buckets, pool covers, pet water dishes, discarded tires, and birdbaths on a regular basis. Those who may choose to use standing water for décor or out of necessity in their yard, such as bird baths and pet water bowls, are advised to change this water every seven days. Keeping vegetation cut back and not over-watering yards also helps.”
Bradshaw said the district uses a fogging truck and sprays permethrin to kill mosquitoes.
“We drive around rural dirt roads in areas known to have mosquitoes at about 10 mph and spray to kill them,” he said.
“Another thing we’re planning on doing is using an airplane to treat about 10,000 acres in the northern part of the district in the Lake Point, Stansbury area,” Bradshaw said.
The manager said there were no detections of West Nile virus in mosquitoes they sampled last year.
“We did have three horses infected last year and they were treated by a veterinarian,” Bradshaw said. “There were 35 horses infected last year in the state, but none so far this year.”
As of Aug. 7, a total of 40 states and the District of Columbia had reported West Nile virus infections in people, birds or mosquitoes in 2018, according to the CDC.
Overall, 106 cases of West Nile virus in people had been reported to the CDC. Of these, 62 were classified as neuroinvasive disease (such as meningitis or encephalitis) and 44 were classified as non-neuroinvasive disease.