On the heels of the first confirmed West Nile virus infection in the state for 2019 in a Gillette woman, state officials said routine testing had also confirmed the presence of the virus June 13 in a batch of mosquitoes in Laramie.
At several locations around the state, local officials typically collect samples of mosquitoes in traps. Those traps are sent to the Wyoming State Veterinary Laboratory at the University of Wyoming in Laramie, where the insects are tested for the presence of the virus.
Those tests don’t usually indicate the active virus until much later in the summer months, local and state public health officials said. But, despite the unusually cool spring this year, the virus has shown up several weeks early.
“It is early,” said Courtney Smith, surveillance epidemiologist for the Wyoming Department of Public Health in Cheyenne. “I don’t have a good answer for why.”
Johnson County is one of the handful of counties that typically doesn’t trap mosquitoes for testing for the virus, said Rod Litzel, Weed and Pest District supervisor for the county. To the best of his knowledge, there has never been a confirmed positive case of West Nile that originated locally.
“There tend to be some perennial areas for the West Nile virus,” Litzel said. “Gillette is one of them.
“But it’s problematic trying to find where some of that gets originated. People move around,” he said. “Horses move around. But there are for darn sure some mosquitoes out there this year, unfortunately.”
The county did have a program in conjunction with the city of Buffalo to routinely spray for mosquitoes during the summer months, Litzel said. But, due to problems finding staff, as well as dwindling county budgets, that program was disbanded, effective this year.
Litzel said Buffalo routinely sprays to combat mosquitoes in town and around the Clear Creek drainage.
Les Hook, director of the city’s Public Works Department, said the department started its spraying program to combat adult mosquitoes on June 13, with a follow-up application on June 17.
“We usually don’t start – a lot of the time, it isn’t until the first of July,” Hook said. “But they’re already thick this year, so here we are.”
The usual procedure is to “do the whole town as quick as we can at the start, then go by complaints,” he said, with heavy-use areas, including the city parks, typically treated weekly.
The city is currently spraying an insecticide that eliminates adult mosquitoes, Hook said. The department isn’t set up to apply larvicides inside city limits or around Clear Creek.
In rural Johnson County, the Weed and Pest District makes larvicidal chemicals – designed to kill the early, larval stages of the insects – available to private landowners with ponds or other water features where mosquitoes breed, Litzel said.
“The city is in charge of doing larvicide applications in the city limits,” Litzel said. “Private landowners can come in and get chemicals to do their own treatments.”
Those treatments are “an effective method,” said Tricia Thompson, nurse manager for the Johnson County Public Health Department. “It’s one of the methods we do use in hot spots to actually prevent West Nile virus. If property owners do that, it would cut down on the possibility of contaminated mosquitoes.”
And there shouldn’t be any financial concerns for the city with the early start to spraying duties, Hook said. His departmental budget has a sufficient financial cushion built in to cover the additional costs for overtime pay, as well as the chemicals.
In spite of the early appearance of the virus, state and local health officials say people shouldn’t necessarily swear off future summer plans. While unusual, confirmation of the virus this early in the season isn’t a definitive harbinger of things to come, Smith said.
“This doesn’t necessarily mean it’s going to be a bad year,” Smith said.
“Our climate takes care of a lot of the other diseases – they just don’t do well in our environment,” Thompson said. “We’re not like a really hot and humid or moist area for them to continue to breed diseases, or where mosquitoes thrive.
“We’ve had an unseasonably wet spring this year that’s lasting for a long period of time,” she said. “It’s hard to say what’s going to happen when summer actually comes upon us and how that will affect the mosquito populations.”
Even if this year is particularly bad for mosquitoes, most who contract West Nile virus won’t show any symptoms of the infection at all, Smith and Thompson said. For the small percentage who do, even fewer will be at risk for developing the more serious, neuroinvasive variant of the disease, characterized by symptoms that include fever, coma, severe headache and disorientation, which can become life-threatening, Thompson said.
“Those who do get it might attribute it to something else or they may not get sick at all,” she said. “A lot who do become sick just develop flu-like symptoms – body aches, headaches, swollen lymph nodes.”
Litzel, Thompson and Smith all reiterated the need for people to take precautions to lessen the likelihood that mosquitoes will be able to breed and to protect themselves and loved ones from the pests when they inevitably do breed. Individuals can do away with any sources of standing or stagnant water, for example, by emptying buckets or old tires on their property and by dumping and scrubbing bird baths and other small water features at least weekly.
People should also avoid outdoor activities around sunrise and sunset, when mosquitoes are most active. Use of insect repellents containing the active ingredient DEET and wearing long-sleeved shirts and long pants can go a long way to protect from feeding mosquitoes.
Insect repellent should not be used with babies, Smith said. Instead, dress infants in clothing that covers their arms and legs and cover their strollers with a fine mesh mosquito netting to protect them.