Hot and dry? Weather conditions mean fewer mosquitoes this summer

LANSING — Looking for birds, Nancy Glass, with her binoculars, and her husband Joe, with his camera, didn't find much over the water at Crego Park Friday morning.

They also didn't find pesky mosquitoes.

"I haven't really seen many this year," Nancy Glass said.

She and her husband have spent the last few years of their retirement birdwatching at various Greater Lansing parks and they've noticed that this summer seems to be a tough one for the region's mosquitoes.

Drought conditions in Michigan have kept the buzzing, blood-seeking mosquitoes that carry some of the worst diseases at bay, confirmed Edward Walker, a Michigan State University professor and mosquito researcher.

"It’s a demonstrably low year for mosquitoes this year," he said.

Still, he recommends repellants and protective clothing.

Walker warned there is plenty of time left for a rebound in their season, which typically wraps in September or early October.

And any bite you get could still transmit serious viruses like West Nile and Eastern equine encephalitis, even though this summer's odds are better than most.

In 2021, the state was swarmed with mosquitoes from a wet June. Walker, who has spent his career with mosquitoes, said then he wouldn't even walk his dog at night because the insects were so thick.

This year, a state collection of nearly 35,000 mosquitoes is indicating it will be a below average season for West Nile virus, one of the most serious mosquito-borne diseases found in Michigan, said Chelsea Wuth, a spokesperson for the Michigan Department of Health and Human Services.

No cases of the three main mosquito-borne diseases for humans in Michigan - West Nile virus, Eastern equine encephalitis and Jamestown Canyon - have been found in people or animals this year, but a handful of mosquito pools, which can be a small puddle or a swimming pool, have been found by local county health officials to have virus-carrying mosquitoes.

According to the weekly Michigan Arbovirus Surveillance Report:

• In Bay County, officials have found a mosquito pool with Eastern equine encephalitis, one with West Nile virus and two pools with Jamestown Canyon virus.

• In Barry County, officials have found a mosquito pool with Eastern equine encephalitis.

• In Saginaw County, officials have found a mosquito pool with Jamestown Canyon virus.

• In Kalamazoo County, officials have found a mosquito pool with West Nile virus.

• In Washtenaw County, officials have found three pools with Jamestown Canyon virus and one with West Nile virus

Given the dry and hot weather this year, Walker said it is surprising to him to see so few cases of West Nile virus because it is typically carried by mosquitoes that live in storm drains. A lack of rain typically allows them to thrive, since there's no water to flush them out.

However, he said recent discoveries in Indiana and in Kalamazoo County may indicate mosquito activity is picking up, at least among the type of mosquitoes that carry West Nile virus.

State Veterinarian Nora Wineland issued a warning this month after the EEE discovery, recommending livestock be protected in a barn under a fan from dusk to dawn, as well as other precautions including consulting with a veterinarian about vaccines.

According to the Michigan Department of Agriculture and Rural Development, EEE can be fatal in 90% of horses that fall ill and 33% of humans who fall ill.

Dog heartworm is the most common mosquito-spread disease in Michigan, Walker said, but it is unlikely to affect humans. Officials suggest precautions including checking under their fur and between toes, as well as preventative measures like medications. There also are steps both humans and pets could take, such as avoiding the outdoors from dusk to dawn, when many mosquitoes are most active.

Concerns about malaria

One of the most threatening mosquito-borne diseases, malaria, had not been locally transmitted in the United States in 20 years but officials have found several cases in Florida and one in Texas this summer.

"It's more than a blip on the radar, we have had no activity like that in 20 years and it has got our attention," Walker said.

There are typically several cases of malaria in Michigan. In the five years from 2017 to 2021, the state had an average of about 25 cases a year, but they have all been attributed to international travel rather than being bit by a mosquito in the United States.

The last locally-acquired case of malaria in Michigan was in metro Detroit in 1995 and it was the only such case in Michigan in about 50 years at that point.

Before the 1995 case, the last time locally-acquired malaria was found this far north in America was in 1972, according to a Centers for Disease Prevention and Control study into the 1995 case. Walker was part of that 1995 investigation.

Until the turn of the 1900s, malaria was relatively common in Michigan. The first graduating class of what is now Michigan State University studied agriculture in the summer and 70% of them contracted malaria, Walker said.

Year-round mosquito risks

Michigan's winters can help keep mosquito counts down but female mosquitoes can survive the cold and continue to carry the disease into spring, Walker said.

"The parasite can handle the fact of our winters," he said. "Most of the infections are in tropical places, for socioeconomic and other reasons."

Mosquitoes in the southern states seem to remain a bigger concern than those in Michigan.

The Centers for Disease Control and Prevention was founded in the wake of WWII to fight against malaria in Southern states, and the surveillance system it set in place continues to be an effective defense, the federal organization says.

“We shouldn’t be surprised that we’re going to have sporadic outbreaks again,” said Dr. Thom Eisele, professor and director of the Center for Applied Malaria Research and Evaluation at Tulane University School of Public Health and Tropic Medicine, to USA Today. “The ingredients are here for transmission to happen, but we have a lot of safeguards.”

Michigan residents are far more likely to encounter a regular mosquito bite than something linked to the worrying viruses, Walker said.

"There’s always the potential for malaria to happen like this," Walker said.

He said people should take normal precautions to avoid mosquito bites, as well as ticks.

Wear long sleeves and pants, use effective and safe bug repellent and check for bites and bugs after being outdoors in wooded or grassy areas, Walker said.

Contact Mike Ellis at mellis@lsj.com or 517-267-0415

This article originally appeared on Lansing State Journal: Expect fewer mosquitoes than usual, but the ones left can carry disease