Synonym: Entamoeba gingivalis var. equi.
Nieschulz (1924) found this amoeba in the mouths of several horses in Holland, and Simitch (1938a) cultured it from the mouths of 16 out of 22 mares and 3 out of 3 donkeys in Serbia. It is morphologically identical with E. gingivalis, except that its trophozoites are somewhat smaller, measuring 7 to 14 u in diameter. It has no cysts. Simitch (1938a) was unable to infect horses with E. gingivalis (syn., E. canibuccalis) from the dog or to infect dogs with the horse form. Hence he considered the latter to be a new species. Further study is needed to learn whether this view is correct.
Tumka (1959) found this amoeba on the coating of the teeth of 6 out of 32 domestic pigs from the vicinity of Leningrad. It resembles E. gingivalis but is in its lower size range, measuring 7 to 12 u with a mean length of 9 u. when fixed and stained. It is questionable whether this is a separate species.
This species was found in the feces of a dog in Brazil. No cysts were seen. The trophozoites were 10 to 36 u long. Their pseudopods and nuclei resembled those of E. histolytica, but they differed from it in containing many ingested bacteria and in having a sac-like appendage at the posterior end containing dense, darkly staining cytoplasm and undigested bacteria.
Synonym: Endamoeba gedoelsti.
Hsiung (1930) found this amoeba in the cecum or colon of 7 out of 46 horses in Iowa. What was probably the same species had been seen in the horse by Gedoelst (1911) in Belgium and Fantham (1920) in South Africa. No cysts have been seen. The trophozoites are 7 to 13 u long and contain bacteria in their food vacuoles. The nucleus is similar to that of E. coli, with an eccentric endosome surrounded by a halo and a row of peripheral chromatin granules.
Fantham (1923) described this species from the intestine and reticulum of a lightly infected goat in South Africa. It is very large, one streaming individual measuring 34 by 24 u. The pseudopods are short and lobose, and red cells may be ingested. The nucleus is oval, 9 to 10 u in diameter, with an eccentric endosome. No cysts were seen. The relationship of this form to other goat amoebae remains to be determined.
Brenon (1953) tabulated 3 deaths from amoebic dysentery among the causes of death he observed in 1005 chinchillas in California. Since the amoebae of chinchillas have apparently not been described, they cannot be assigned to any species.