These may stay itchy for several days, sometimes causing sleepless nights. But – usually after a few hours, though it can take up to two days – the unfortunate human reacts: the skin breaks out in red, itchy lumps. The parasite soon dies, as it cannot live in a human. Mistaking the swimmer for a desirable duck, the confused parasite burrows into the outer layer of human skin. The cercaria might, on its journey, meet a human swimmer. Eventually the cercaria hatches and sets off to find a waterfowl host to begin the cycle again. As lakes and rivers warm up in summer, parasite eggs leave the host bird for an intermediate host, an aquatic snail. These parasites normally live in waterfowl. This parasite (of the family Schistosomatidae) causes ‘swimmer’s itch’ or more correctly cercarial dermatitis: an allergic reaction to the parasite – in its cercarial stage – burrowing into your skin. Sadly, in summer, there is a serpent in our garden: a tiny, fork-tailed, wormy parasite. Swimming at sunset, walking across moors or city parks to splash into dawn: these are glimpses of paradise for an outdoor swimmer. “(Swimmer’s itch) can be at any lake, so you should always follow preventable measures,” Green said.Ĭontact the regional Minnesota DNR office or the city of Detroit Lakes for any additional information.Susie Symes is your guide to protecting yourself against cercarial dermatitis, also known as swimmer’s itch One can reduce the likelihood of getting swimmer’s itch by not feeding waterfowl or allowing them to congregate near shorelines, drying off and showering soon after leaving the water, changing out of wet swimsuits as soon as possible, cleaning beaches of weeds or other debris that have washed up on shorelines and encouraging kids not to wade or play in shallow water. The spray is not 100 percent successful in preventing outbreaks so the DNR recommends following several preventable measures. He said that copper sulfate is a “non-invasive chemical” and they spray such a small amount that it will not permanently harm the habitat of the lake. “The snails are in the weeds, so it has probably gotten better over the years because we cleaned the lake up so much,” Green said. In addition, the city of Detroit Lakes hauled truckloads of weeds from the city beach to help prevent swimmer’s itch a few years ago. “We are only allowed to do it twice per year because they only permit us twice a year,” Green said.Īccording to DNR regulations, the area permitted to spray copper sulfate shall not exceed 300 feet along shore by 300 feet lakeward in the marina area and 3,180 feet along shore by 100 feet lakeward along the city beach. “We try to target around the times when we think the beach will be more populated,” Green said.Īny chemical treatment in the water requires a permit from the Minnesota Department of Natural Resources. To control severe infestations of snails during this time, an application of copper sulfate is sprayed along infested shorelines. Swimmer’s itch typically occurs in late June or early July when lakes are near their warmest summer temperatures. This causes skin irritation that turns into itchy, mosquito bite-like welts. Luckily, humans are not suitable hosts for the cercariae due to their high immune system, so they die shortly after penetrating the skin. It’s during this stage that cercariae come into contact with humans and cause swimmer’s itch. Then the miracidium swim in search of an intermediate host, which can be one of four species of snail that inhabit shallow waters in Minnesota.Īfter three to four weeks in the snail, a second free-swimming stage (cercariae) emerges in search of a primary host (bird or mammal) to complete its life cycle. The adult worm sheds its eggs into the feces of the host, and the eggs are released into the water where they hatch into free-swimming miracidia. It comes from a microscopic flatworm parasite (schistosome cercariae) that lives as an adult in aquatic birds or mammals, usually waterfowl.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |