Disease: Swimmer's Itch

Summer swimming in ponds and lakes should be tempered by an understanding of this dermatitis. This disease is also called cercarial dermatitis. It involves a non-human schistosome. Commonly called swimmers itch, it is associated with waterfowl, snails, and warmer waters. The skin reaction is due to the attempts of the snail and bird parasite to penetrate human skin. It is considered a benign conditon and as an allergic reaction may vary in frequency and incidence from person to person. It is not spread between individuals:

http://www.cdc.gov/ncidod/dpd/parasites/cercarialdermatitis/factsht_cercarialdermatitis.htm

http://www.aocd.org/skin/dermatologic_diseases/swimmers_itch.html

http://www.cdc.gov/mmwr/preview/mmwrhtml/00001145.htm

http://www.dpd.cdc.gov/DPDX/HTML/Frames/A-F/CercarialDermatitis/body_CercarialDermatitis_page1.htm



Causal Agent:
Cercarial dermatitis is caused by the cercariae of certain species of schistosomes whose normal hosts are birds and mammals other than humans. These cercariae seem to have a chemotrophic reaction to secretions from the skin and are not as host-specific as other types of schistosomes. They attempt to, and, sometimes may actually, enter human skin. The penetration causes a dermatitis which is usually accompanied with intense itching, but the cercariae do not mature into adults in the human body. Cases of cercarial dermatitis can occur in both fresh and brackish water environments. One species of schistosome often implicated in cases of cercarial dermatitis is Austrobilharzia variglandis, whose normal hosts are ducks. The snail, Nassarius obsoletus, is the intermediate host for this species and can be found at marine beaches in temperate climates. Cercarial dermatitis should not be confused with seabather's eruption, which is caused by the larval stage of cnidarians (e.g., jellyfish). The areas of skin affected by seabather's eruption is generally under the garments worn by bathers and swimmers where the organisms are trapped after the person leaves the water. Cercarial dermatitis occurs on the exposed skin outside of close-fitting garments.

---

The cure for a fallacious argument is a better argument, not the suppression of ideas.
-- Carl Sagan



Edited 1 time(s). Last edit at 07/20/2009 08:39PM by Frank Furter.

Quote

The areas of skin affected by seabather's eruption is generally under the garments worn by bathers and swimmers where the organisms are trapped after the person leaves the water.

There's a way to avoid that.