What is a host for Schistoma and how are humans affected by this?

Answer 1

mansoni is a significant parasite of humans. Of the trematodes, schistosomes are atypical in that the adult stages have two sexes dioecious and are located in blood vessels of the definitive host. Most other trematodes are hermaphroditic and are found in the intestinal tract, or organs such as the liver. The lifecycle of schistosomes includes two hosts: a definitive host (i.e. man) where the parasite undergoes sexual reproduction, and a single intermediate snail host where there are a number of asexual reproductive stages. Schistoma mansoni is one of the major agents of schistosomiasis.

Schistosoma mansoni is a parasite that is found in Africa, Madagascar, parts of South America (such as Venezuela and Brazil), Puerto Rico and the West Indies.

In intestinal schistosomiasis, eggs become lodged in the intestinal wall and cause an immune system reaction called a granulomatous reaction. This immune response can lead to obstruction of the colon and blood loss. The infected individual may have what appears to be a potbelly. Eggs can also become lodged in the liver, leading to high blood pressure through the liver, enlarged spleen, the build-up of fluid in the abdomen ascites), and potentially life-threatening dilations or swollen areas in the esophagus or gastrointestinal tract that can tear and bleed profusely (esophageal varices). Rarely, the central nervous system may be affected. Individuals with chronic active schistosomiasis may not complain of typical symptoms.

Answer 2

Schistosomes commonly live in snails as a primary (?) host. They most definitely affect humans from North Africa around through Asia, they're devastating parasites. Do a google on schistosomiasis and you should get loads of references.