Final answer:
The protozoan that causes severe dysentery is Entamoeba histolytica. This organism causes amoebiasis, which can lead to serious complications or even death, and it is transmitted through fecally contaminated food or water. Proper sanitation and hygiene are critical for preventing this disease.
Step-by-step explanation:
The protozoan associated with the ability to cause severe dysentery is Entamoeba histolytica. This parasitic protozoan causes a disease known as amoebiasis, which, when severe, is referred to as amoebic dysentery. Entamoeba histolytica is transmitted via fecal contamination of water or food and can lead to serious health conditions and is even fatal in some cases.
Amoebiasis can occur with the ingestion of as few as 10 cysts, making it highly infectious and a significant health concern, especially in the developing world where it's among the leading causes of death from parasitic diseases. It is important to note that while other protozoans like Giardia lamblia can cause severe diarrhea and gastrointestinal upset, they do not cause amoebic dysentery.
Prevention strategies for amoebiasis include proper sanitation, safe drinking water supplies, and good personal hygiene practices to avoid the spread of this disease. In areas with endemic amoebiasis, measures such as boiling or filtering water and ensuring food is properly cooked are essential.