(Radio Iowa) – The State Hygienic Lab has confirmed the first case of West Nile Virus this year in a man in Harrison County. Iowa State University entomologist Ryan Smith oversees the state’s mosquito surveillance program. “This year has been somewhat interesting in the fact that as we got into May and early June, we didn’t see a whole lot of mosquito activity,” he says, “and then later in June, especially as when we started seeing some of the heavy rainfall and flooding, really, across the state, and with that, I think we saw a big explosion of our mosquito numbers.”

The rains ended the drought and left the water that is key for mosquito breeding. “Mosquitoes take advantage of standing water. Any kind of flowing or moving water doesn’t allow for the juvenile stages of mosquitoes to survive, and so they really do thrive on that flooded or standing water in many of these locations,” Smith says. “And especially those counties that were impacted the most, especially out in western Iowa. I think we’ve seen really high numbers.”

He experienced the mosquito explosion first hand. “We’ve actually responded to some of the flooding that occurred in Sioux County this year, and you know, we saw really high numbers, and it doesn’t surprise me that we would have that kind of carry on, and many of the other affected areas that we kind of been able to trap in,” Smith says. Smith says there’s been an increase in disease carrying mosquitoes as well as those that are simply a nuisance. “Those are ones that will bite us, you know, and they’re going to be annoying, and, you know, that’s why we call them a nuisance,” He says. “Whereas others can actually kind of do the same. They can bite humans, but they can also transmit disease. And those are the ones that you know, at least from my perspective, that we really do worry about.”

The state Health Department recommends you dump out standing water to help cut the number of mosquitoes. Smith says that does work. “These mosquitoes usually don’t travel very far, and so if you can reduce places where they might breed, then more than likely you’re also going to reduce the impact of where you might find adult mosquitoes,” Smith says.

The Health Department also recommends that you wear mosquito repellent when outdoors to prevent mosquito bites. Mosquitoes are most active at dawn and dusk. The Health Department says those infected with West Nile may not experience any signs or symptoms of the virus. Some people experience minor symptoms like fever and mild headache, while others can develop serious symptoms such as a high fever, headache, disorientation, and muscle weakness. There were 17 confirmed cases of West Nile virus in 2023, and one death.