is shigella a bacteria or parasite
By Liji Thomas, MD. Dysentery is an infection of the intestines which causes the passage of bloody stools mixed with mucus. It is caused either by bacteria such as Shigella, or by parasites such as Entamoeba.These forms are called bacillary dysentery, or shigellosis, and amoebic dysentery respectively.iagnosis is based on a history of possible contact with the parasite or bacteria, such as travel abroad, confirmed by other tests: 1  Blood tests for Entamoeba or Shigella. 2  Stool tests. 3  Microscopy for the presence of the parasite or bacteria.