142 



THE AMOEBAE 



ENTAMOEBA HARTMANNI 

 VON PROWAZEK, 1912 



As mentioned above, E. kartmanni 

 closely resembles the small race of E. 

 histolytica. It can be differentiated by 

 careful examination of hematoxylin-stained 

 preparations. Burrows (1959) compared 

 the two species. Most trophozoites of E. 

 hartmanni are smaller than those of E. 

 histolytica. Rounded trophozoites of E. 

 hartmanni range from 3 to 10. Sjix in diam- 

 eter, while those of E. histolytica are 

 6. 5|i or more in diameter. The tropho- 

 zoite nucleus of E. hartmanni is usually 

 2. to 2. 5 fi in diameter but may range 

 from 1. 5 to 3. 2^ , while that of E. his- 

 tolytica is usually 3.0 to 3. 5fj, in diameter 

 but may range from 2.8 to 3. 8/i . The 

 peripheral chromatin of E. hartmanni is 

 more variable in its arrangement than 

 that of E. histolytica and may consist of 

 discrete granules with wide spaces be- 

 tween them, a crescent of granules on one 

 side of the nucleus, or a single large bar 

 of chromatin with several small granules 

 around the membrane; the peripheral 

 chromatin of E. histolytica is generally 

 distributed uniformly along the nuclear 

 membrane. 



Most cysts of E. Itartmanni are 

 smaller than those of E. histolytica. They 

 range from 3. 8 to 8. Ofi in diameter while 

 those of small race E. histolytica are 

 5. 5(1 or more in diameter. The cyst nu- 

 clei of E. hartmanni are 1. 8 to 3. Ojj, in 

 diameter in uninucleate cysts, 1. 3 to 2.0 )i 

 in binucleate cysts and 0. 7 to 1. 7 /i in 

 tetranucleate cysts; those of small race 

 E. histolytica are 2.4 to 2.8 ji in diameter 

 in uninucleate cysts, 2. to 2. 8/j, in binu- 

 cleate cysts and 1.4 to 2.2 /i in tetranu- 

 cleate cysts. The cysts of E. liartmanni 

 seldom contain large glycogen bodies, but 

 nearly all of them have a few to many 

 small vacuoles; the cysts of E. histolytica 

 generally have one large glycogen vacuole 

 or no vacuoles. The chromatoid bodies of 

 the two species are similar. 



Freedman and Elsdon-Dew (1959) 

 suggested that, until an accurate, prac- 

 tical method of separation is devised, 

 mean sizes of 12/i for trophozoites and 



10/i for cysts be used as the dividing line 

 between E. histolytica and E. liartmanni. 

 The latter criterion has been used for 

 some time to distinguish between the cysts 

 of large and small race E. histolytica by 

 those who do not accept the name E. liart- 

 manni (Shaffer et al. , 1958). 



The incidence of E. liartmanni in an- 

 imals and man is unknown because in the 

 past it has ordinarily been lumped with 

 E. histolytica. According to Burrows 

 (1957, 1959) about half of the reported 

 cases of E. histolytica in the United States 

 were actually E. hartmanni. Further 

 studies in which the two species are sep- 

 arated will throw light on this point, which 

 is important because E. hartmanni is non- 

 pathogenic. 



ENTAMOEBA MOSHKOVSKII 

 CHALAYA, 1941 



This species occurs in sewage. It is 

 not a parasite of animals, but of the mu- 

 nicipal digestive tract. It was found in 

 the sewage disposal plant and sewer sys- 

 tem of Moscow by Chalaya (1941, 1947), 

 in sewage in Leningrad by Gnezdilov (1947), 

 in sewage in Brazil by Amaral and Azzi 

 Leal (1949), in sewage in London by Neal 

 (1950, 1953), and in sewage in Quebec by 

 Lachance (1959). Probably the same or- 

 ganism was found in sewage in California 

 by Wright, Cram and Nolan (1942), altho 

 they did not name it. Chalaya (1947) cul- 

 tivated it from the water of 2 ponds and a 

 river in Russia. Altho E. moshkovskii 

 is not parasitic, the possibility of its ac- 

 cidental presence in fecal samples is of 

 concern in diagnosis. 



E. moshkovskii resembles E. histo- 

 lytica morphologically. The trophozoites 

 are active, 9 to 29fi (usually 11 to 13(j.) 

 in diameter. The nucleus has a small, 

 central endosome and a peripheral layer 

 of fine granules. The cysts are generally 

 spherical, 7 to 17 /i in diameter. They 

 contain a very large glycogen vacuole at 

 first which is eventually absorbed as the 

 cysts age. The chromatoid bodies are 

 large, rather elongate, and have rounded 

 ends. The mature cysts have 4 nuclei. 



