Marjorie Mathison Hance, Big Pelican Lake Property Owners Taskforce, and Dr Curtis Blakespoor, a leading expert on swimmer’s itch from Cornell University) on WDAY Radio’s The Jay Thomas Show
PELICAN RAPIDS, MINN – Cases of swimmer’s itch, a skin rash caused by an allergic reaction to microscopic parasites infecting some birds and mammals, are being reported in Lakes Country this summer.
According to Marjorie Mathison Hance, who has lived on Pelican Lake for 57 years, Merganser ducks were first spotted in 2020 on the lake, and the first case of swimmer’s itch surfaced on the beach two months later.
“We started having broods of birds, and they stayed all summer,” Hance told WDAY Radio’s The Jay Thomas Show. “The reason why that’s important is that it’s the babies that produce the most parasite.”
She said the babies shed 25 times the number of parasites that the adults have.
While 2020 was the first time Hance had swimmer’s itch, she said that it had surfaced around the lake before.
“It was certainly nothing like this,” she said, referring to the surge in amount of cases seen on the lake this year.
Currently there are four broods of mergansers on the lake, with a total of 41 babies.
Dr. Curtis Blakespoor, who is a leading expert on swimmer’s itch from Cornell University in Ithaca, N.Y., said the 41 ducklings are the source of the issue. He says the issue lies with nesting sites on lakes such as Pelican Lake.
“Mergansers are very picky about where they nest,” he said. “So if you can get the nest and take the ducklings off and move them 100 miles away, they’re going to imprint on that area, and they’re going to come back to the area where they get relocated, not to the Pelican Lake area.”
Catching the ducklings for a period of two or three years will decrease the snail levels in the lake, which will then decrease the infection because there’s not as many parasites in the water.
“So you do a kind of two-fold approach,” Dr. Blakespoor said. “You take the ducklings off and you try to find the nests where the ducklings are produced every year. And if you can get a couple of nests every year, you can knock down your merganser population without having to kill a bird.”
He says swimmer’s itch is going to be found in every lake – but different species are said to be the cause of the problem.
“In lakes where there aren’t any boat launches, or there are very few people, it’s not the common merganser species,” Dr. Blakespoor said. “It’s a species carried in muskrats or sometimes blackbirds.”
He cautions that some lakes that have mergansers may not have swimmer’s itch. That’s because it’s missing the snail that carries the infection.
Dr. Blakespoor says the Minnesota Department of Natural Resources has been given a few options to take care of the issue. One of the options is to capture the mergansers and test them for bird flu.
“The big reason folks are really nervous, especially in Minnesota with all the poultry industry, is moving the birds and transmitting bird flu,” he said. “But there’s a test that we’re willing to administer to each duckling, and if it’s positive, obviously, the DNR would want to euthanize them. But if it’s not, we could relocated it.”
Another option is to have veterinarians give drugs to take care of the problem, but the permission has not been given to do that.
“In fact, we’ve been steered away from using that option by the Minnesota DNR,” Dr. Blakespoor said.
