Re: duck lice

Posted by Julie on April 13, 2003 at 02:15:06:

In Reply to: duck lice posted by daveeda on August 23, 2002 at 21:03:28:

In all likelihood, what you call duck lice is actually Swimmer's Itch. It is common on the West Coast of North America, almost all the way to the Arctic Circle.

It is a bird-based parasite,(a schistosome) but can attack any animal. Unless you are a bird or a rodent, it does not cause parasitosis. It does cause dermatitis, and all exposures following your first encounter will tend to have a strong response.

How does this parasite work?
1. A bird or rodent defecates in the water, releasing eggs.
2. Egg hatches and "larva" (miracidium) swims to a water snail and enters its flesh, parasitising it.
3. "Larva" develops to next stage in the snail and exits snail into the water as a cercaria.
4. Cercaria looks for a vertebrate host. If a bird or rodent is found, cercaria penetrates skin and enters animal. Inside the animal, it hopes to live in the circulatory system, find a mate, and breed, leading to the animal defecating schistosome eggs and starting the cycle over again.

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