Dysentery is a disease caused by bacteria, amoeba, and viruses. Caused by poor hygiene, dysentery is easily transmitted from person to person. It can result from contaminated water and unwashed food. The most common causes of dysentery include:

Consuming contaminated water
Food preparation by someone with poor hygiene and who doesn't wash their hands
Sexual contact, especially involving the anus
Bacillary dysentery arises when the infection worsens due to foreign bacteria entering the body. Some of the most common bacteria that cause bacillary dysentery include:

Shigella bacteria
Salmonella bacteria
Campylobacter
E. coli infection
Amoebiasis