#Swimmers itch bites skin#
#Swimmers itch bites series#

No, a papule forms only where a cercaria has entered the skin of a person. Further research is also warranted into the effects of these parasites on waterfowl. Further medical research is certainly warranted. This sensitivity will rarely disappear it usually gets worse on subsequent exposure.Īnecdotal and research reports indicate that, in some humans, these parasites may penetrate beyond the skin in their attempt to complete their life cycle. In humans and other mammals, the parasite is killed by the immune system, and may cause dermatitis in individuals who have been previously sensitized. They are shed by the snail in great numbers to swim to the water surface in search of their primary host to complete the life cycle. They are virtually invisible, but can be seen in a vial of water held up to light. Upon shed of the parasites, the snail is exhausted of nutrients and dies.įurcocercariae look like microscopic clear tadpoles with forked tails. Finally, several tens of sporocysts produce thousands of furcocercariae. They are nourished by absorbing the digested food of the snail.

#Swimmers itch bites series#

In the heart, it becomes a mother sporocyst (bag of spores), which become daughter sporocysts to migrate into the hepatopancreas where they each produce another series of daughter sporocysts. Upon encountering a snail, the miracidium penetrates the snail’s foot and migrates to the heart. The development of each of these parasites in the host snail is identical. This parasite, only recently found in New Zealand, is neuropathogenic and has been shown experimentally to cause paralysis in ducks and in mice. When the bird puts its bill in the water, the eggs hatch and the miracidia then search for their snail host. They become adult in the meninges and then migrate to the nasal tissue where embryonated eggs are deposited. Trichobilharzia regenti cercariae penetrate the bird’s skin, become schistosomules, enter the peripheral nerves and travel to the central nervous system and the brain. Upon reaching the water the eggs hatch to release a single miracidium, which searches for a snail. The female migrates in the blood vessels to the intestine to deposit embryonated eggs which pass out of the bird with faeces. They become adult male or female worms and mate in the blood vessels of the liver and mesentery. Trichobilharzia longicauda cercariae penetrate the bird’s skin, become schistosomules, enter the blood vessels, and travel to the heart, lungs, and the liver. They each follow different paths in the scaup. In New Zealand, two avian schistosomes have been found concurrently in the scaup and individually in the snail. The secondary intermediate host is the lymnaeid snail, Austropeplea tomentosa known previously as Lymnaea tomentose. Where these waterfowl are found, there will be Duck Itch. The primary definitive host in New Zealand is the New Zealand Scaup, Aythya novaeseelandiae. The schistosome family includes parasites infecting 200+ million humans throughout the world. The parasite is in the genera of world-wide avian schistosomes that complete their life cycle in two stages. Hot showers, rigorous towelling-off, cold temperatures, calm conditions…none of these are proven to prevent duck itch.ĭuck Itch, or schistosome cercarial dermatitis is a reaction that some people get when parasitic flatworms penetrate the skin.You may use antihistamines or anti-itch creams to soothe duck itch.Duck itch tends to be more prevalent in shallow areas with an onshore breeze.Apply to exposed areas (face, hands, feet) as duck itch doesn’t generally get into your wetsuit. Your best shot at preventing it is to wear sunscreen that contains phenoxyethanol (a common preservative).Duck itch is not dangerous or contagious.As a swimmer, what you really need to know is this: Norm Davis is the leading expert (see for comprehensive information and some nice graphics). This annoying ailment is pretty common in Lake Wanaka, and our own Dr. Duck itch presents as raised itchy bumps. Lake Itch, Swimmer’s Itch, the Dreaded Duck Itch…it’s the only real bane of our existence, sandfly bite of swimming.