Final answer:
Dysentery can be caused by two main protozoan parasites: Entamoeba histolytica, which leads to amoebic dysentery, and Giardia lambliathat, which causes giardiasis. Both parasites are transmitted through ingestion of contaminated food or water and can cause severe gastrointestinal symptoms.
Step-by-step explanation:
The parasites that cause dysentery, a severe form of diarrhea, can indeed be problematic for workers and others exposed to contaminated food or water. There are two main protozoan parasites responsible for dysentery, identified by their symptoms and the way they are transmitted.
Amoebiasis (Amebiasis)
Caused by the parasite Entamoeba histolytica, amoebiasis is also known as amoebic dysentery and is a significant health issue, particularly in the developing world. This parasite can cause severe infection and potentially lead to mortality. Transmission typically occurs through the ingestion of as few as 10 cysts in water or food contaminated by feces.
Giardiasis
Giardia lambliathat is another parasite that can cause giardiasis, a type of gastroenteritis leading to symptoms such as diarrhea and nausea. Commonly referred to as backpacker's diarrhea or beaver fever in the United States, Giardia lamblia, also called Giardia intestinalis or Giardia duodenalis, attaches to the intestinal mucosa with a large adhesive disk. This attachment interferes with nutrient absorption and can lead to greasy stools and weight loss. The disease is frequently spread through contaminated food or water following a fecal-oral route.