Schistosomiasis is an infection with a type of blood fluke parasite called schistosomes.
Bilharzia; Katayama fever; Swimmer's itch; Blood fluke; Snail fever
You can get a schistosoma infection through contact with contaminated water. This parasite swims freely in open bodies of fresh water.
When the parasite comes into contact with humans, it burrows into the skin and matures into another stage. Then, it travels to the lungs and liver, where it grows into the adult form of the worm.
The adult worm then travels to its preferred body part, depending on its species. These areas include the:
Schistosomiasis is not usually seen in the United States except for returning travelers or people from other countries who have the infection and are now living in the US. It is common in many tropical and subtropical areas worldwide.
Symptoms vary with the species of worm and the phase of infection.
This infection is usually treated with the drug praziquantel or oxamniquine. This is usually given along with corticosteroids. If the infection is severe or involves the brain, corticosteroids may be given first.
Treatment before significant damage or severe complications occur usually produces good results.
These complications may occur:
Call your provider if you develop symptoms of schistosomiasis, especially if you have:
Follow these steps to avoid getting this infection:
Snails can host this parasite. Getting rid of snails in bodies of water used by humans may help prevent infection.
Bogitsh BJ, Carter CE, Oeltmann TN. Blood flukes. In: Bogitsh BJ, Carter CE, Oeltmann TN, eds. Human Parasitology. 5th ed. London, UK: Elsevier Academic Press; 2019:chap 11.
Carvalho EM, Lima AAM. Schistosomiasis (bilharziasis). In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 355.