Shigellosis
A patient with shigellosis will often recover without antibiotic treatment. However, treatment by antibiotics is usually recommended because the disease is relatively severe, and it is highly contagious. It can be transmitted by "fomites", for example clothes, doorknobs, toilet seats, etc. The antibiotics norfloxacin, ampicillin and cotrimaxozole may be used.
See shigellosis for more information.
Amoebic dysentery
Amoebic dysentery is transmitted by contaminated water, and is well known as a "travellers dysentery", although it is occasionally seen in Western countries. Liver infection, and subsequent amoebic abcesses can occur. It can be treated with metronidazole or related azole drugs.