152 



THI AMOEBAE 



endosome surrounded by a vesicular space 

 containing a single layer of periendosomal 

 granules about midway between the endo- 

 some and the nuclear membrane. Fibrils 

 extend to the nuclear membrane, but 

 there are no peripheral granules inside 

 the membrane. Stabler (1945) described 

 tube-like processes which may be used 

 for feeding in 12% and 27%, respectively, 

 of the trophozoites of 2 human strains. 



The cysts are often irregular in form. 

 They are usually 8 to lOji long, but may 

 range from 5 to 14 fi. They contain a 

 single nucleus in which the periendosomal 

 granules have usually aggregated into a 

 crescent-shaped group at one side of the 

 endosome, pushing it to one side. They 

 contain a large, compact mass of glycogen 

 which stains deeply with iodine. The gly- 

 cogen disappears after 8 to 10 days in 

 feces held at room temperature, and at 

 the same time the cysts die and disinte- 

 grate (von Brand, 1932). There are no 

 chromatoid bodies in the cysts, but they 

 may contain small, deeply staining gran- 

 ules something like volutin granules. 



Life Cycle : /. buelschlii reproduces 

 by binary fission. Pan (1959) studied nu- 

 clear division in the trophozoites. He 

 considered the process unique; his paper 

 should be read for the details. The hap- 

 loid number of chromosomes is usually 

 more than 10--possibly 12. 



Pathogenesis : /. buelschlii is non- 

 pathogenic except under unusual circum- 

 stances. These have never been noted in 

 the pig, but Andrew (1947) reported symp- 

 toms similar to those of chronic E. Iiislo- 

 lytica in a few persons, and Derrick (1948) 

 described a fatal generalized infection in 

 a Japanese soldier captured in New Guinea 

 in which there were ulcers in the stomach, 

 small intestine, large intestine, lymph 

 nodes, lungs and brain. 



Bionomics and Epidemiology : /. 

 buelschlii, like other intestinal amoebae, 

 is transmitted by cysts. 



Cultivation : This species can be cul- 

 tivated in the usual media. 



Treatment : Little is known about 

 treatment for /. buelschlii, but it can be 

 eliminated by emetine. 



Prevention and Control : The same 

 preventive measures recommended for 

 E. hislolylica will also prevent /. buel- 

 schlii infections. 



Genus ENDOUMAX Kuenen and 

 Swellengrebel, 1917 



These are small amoebae. The nu- 

 cleus is vesicular, with a comparatively 

 large, irregularly shaped endosome com- 

 posed of chromatin granules embedded in 

 an achromatic ground substance, and with 

 several achromatic threads connecting the 

 endosome with the nuclear membrane. 

 Cysts are present. This genus occurs in 

 both vertebrates and invertebrates. 



ENDOLIMAX NANA 



(WENYON AND O'CONNOR, 1917) 



BRUG, 1918 



Synonyms : Amoeba Umax. Enta- 

 moeba nana, Endolimax inteslinalis, 

 Endolimax cynomolgi, Endolimax suis, 

 Councilmania tenuis . 



Hosts : Man, pig, gorilla, chimpan- 

 zee, gibbon, macaques and other monkeys 

 and baboons, including AJacaca mulalta, 

 M. irus, M. sinica, M. sancti-johannis, 

 M. lasiotis, M. philippinensis, Papio 

 papiu, Cercocebus aethiops, Cercopith- 

 ecus asca)iius, Gamadyillns sp. , and 

 Erytlirocebns patas (see Mackinnon and 

 Dibb, 1938). These authors also reported 

 a morphologically indistinguishable form 

 from the capybara [Hydrochoerus capybara) 

 and tree porcupine (Coendou prehensilis). 



It is quite likely that E. ratti (see be- 

 low) may be a synonym of E. nana, so that 

 the latter's host range may be even broader 

 than that given above. Chiang (1925) con- 

 sidered E. ratti a separate species because 

 he was unable to infect 14 rats with E. nana 

 from man. However, Kessel (1928) suc- 

 ceeded in doing so, and Smith (1928) found 



