The amount of rain southwest Kansas received in July, especially last weekend, has created an ideal habitat for and uptick in mosquitoes, and local and state officials are warning residents to take preventative measures as a majority of the state is in high-risk for West Nile virus.
According to Dr. Sarah Zukoff, an entomologist with the K-State Southwest Research-Extension Center in Garden City, Finney County is seeing more mosquitoes following the estimated 6 inches of rain the area received late last week and into the weekend.
“We’ve been seeing an uptick in the salt marsh mosquito… that one is basically one that really likes to lay eggs in water,” Zukoff said. “They lay these little rafts of eggs on the surface, then they hatch in about five days. So any water that’s been sitting around with a little bit of organic matter in it, that’s where their eggs will be hatching from. That’s ditches, puddles in pasture, containers in people’s backyards, that sort of thing.”
Zukoff said the salt marsh mosquito is not big in size and blackish-brown in color.
“It’s kind of smaller for mosquitoes, but they have little white stripes on their back legs, and like all mosquitoes, their little back legs stick up,” Zukoff said. “… A person typically wouldn’t be able to make them out because they’re so small…There’s a couple other species that have stripes, as well, so it’s pretty hard to identify them just by looking at them. But as of now, those are the only ones (salt marsh mosquitoes) I’m finding in people’s yards.”
According to Zukoff, the salt marsh mosquito is found nearly everywhere west of the Mississippi River, all the way to California and up to Canada.
“They’re really far reaching,” Zukoff said of the mosquito, which is most active in the early morning and late evening. “They’re really common in California, but they really love the Midwest as well.”
Zukoff said because the mosquito's life cycle only lasts seven to 10 days, and because there is still standing water in areas, a rise in numbers is not unusual.
“The mosquitoes are just kind of now starting up in our county, but what everyone can basically do at home is go through and make sure they are emptying out containers in their backyards, because this species in particular does like those things,” she said. “We’re talking gutters that are clogged, bottom of plant pots that are full of water, any tiny areas where there’s water standing for at least five days, they’ll have mosquitoes in it.”
In mid-July, the Kansas Department of Health and Environment issued a high-risk warning for West Nile virus infections for north-central, south-central and southwest Kansas. The northeast and southeast regions are at moderate risk. And on Tuesday, the KDHE reported two cases of neuroinvasive West Nile virus in two individuals who live in Johnson County.
According to the KDHE, West Nile can be spread to people through mosquito bites, but it is not spread from person to person.
About one in five people who are infected develop a fever and other symptoms. Roughly one out of 150 infected people develop the more severe version of the disease, neuroinvasive disease, which includes swelling of the brain or brain tissue and, in some cases, death. There are no vaccines or medications to treat West Nile. People who have had the virus before are considered immune, according to the KDHE.
“Although for most people, West Nile virus may not cause a great deal of concern, we encourage residents, especially our vulnerable populations, to take steps to prevent infection because of the potential for complications,” Dr. Greg Lakin, chief medical officer of the KDHE, said in a press release.
Most West Nile infections occur in the late summer and early fall, according to the KDHE, and as of July 24, 39 cases of human West Nile virus have been reported nationally.
There were more than 600 cases of the most severe form of the virus and 30 deaths in Kansas from 1999 to 2017.
Symptoms of West Nile virus disease include fever, headache, weakness, muscle pain, arthritis-like pain, gastrointestinal symptoms, and rash typically developing two to 14 days after a bite from an infected mosquito, according to the KDHE.
While a majority of the state is in a high-risk warning for West Nile, it's not something residents should be too concerned about, Zukoff said.
“The whole half of the state is in that high-risk zone, and that’s just because this species is the number one known vector of West Nile virus. It’s something we just look out for because they’re here and its potential to spread that disease,” Zukoff said, noting that if a person has symptoms of the disease, they should consult a doctor.
According to Zukoff, the salt marsh mosquito also can transmit equine encephalitis and St. Louis encephalitis, which also can be harmful to pets.
Roger Calkins, Finney County’s Public Works Director, said on Thursday that the county is currently attempting to make sure that the water on Finney County property is moving to the proper drainage ditch.
“There are two main drainage ditches that collect water and help transport it to the (Arkansas) river,” Calkins said of the two large ditches that run through the city. “Finney County does not have a retention pond that would need circulated or sprayed.”
Calkins added that for areas outside of the county, like Kalvesta, the water drains naturally and occasionally will end up on private property, which the county does not have jurisdiction over.
Sam Curran, Garden City Public Works director, said city crews began treating areas with standing water on Thursday to combat mosquitoes before they hatch.
"It doesn’t matter if it's private property or public property, if we see standing water, we’ve got a pellet shooter and we’ll shoot pellets in there just to help that area," Curran said. "…If there’s standing water, we’re probably treating it."
Curran said that as of Thursday afternoon, the city had not received any major complaints about mosquitos, adding that the city will start spraying regularly.
Curran noted that the city typically treats areas for mosquitoes prior to community events so that they do not become an issue.
If a resident sees an area that has a mosquito problem, Curran encourages them to call the City Public Work Department at (620) 276-1260.
While emptying containers that may hold standing water is one method of getting rid of mosquitoes, Zukoff said using DEET — an active ingredient in most insect sprays — and wearing lighter colors since mosquitos are attracted to darker colors can help prevent mosquitoes from biting.
Anyone who has standing water or even ponds on their properties, also can use mosquito dunks, a biological mosquito control that kills their larvae, Zukoff said. She said anyone considering using mosquito dunks should be aware that they can also kill other insects in or around the ponds.
Residents with swimming pools that are treated with chlorine do not have to worry about mosquitoes laying eggs in them because the chlorine will kill the eggs, Zukoff said.
“Anything not treated is a good habitat for the mosquito,” she said.
Contact Josh Harbour at firstname.lastname@example.org.