Which parasite is known to cause dysentery, abdominal pain, and is transmitted through water contaminated with cysts?

Entamoeba histolytica is recognized for causing dysentery, which is characterized by severe diarrhea with the presence of blood or mucus, and abdominal pain. This protozoan parasite is transmitted through environments contaminated with fecal matter, particularly in water sources containing its cysts. Upon ingestion, the cysts release trophozoites in the intestines that can invade the intestinal mucosa, leading to the symptoms noted.

The other parasites listed are associated with different pathologies or modes of transmission. Giardia lamblia typically causes giardiasis, characterized by malabsorption and greasy stools, while Cryptosporidium parvum is known for causing watery diarrhea, primarily affecting immunocompromised individuals. Schistosoma mansoni is a trematode that causes schistosomiasis and is transmitted through skin contact with contaminated water, not through water containing cysts. Hence, the association of Entamoeba histolytica with dysentery and cyst transmission distinguishes it as the correct answer.