Entamoeba

Entamoeba Casagrandi & Barbagallo, 1895 (ref. ID; 1618)

Synonym Poneramoeba Luhe (ref. ID; 1618)

[ref. ID; 1618]
Nucleus vesicular, with a comparatively small endosome, located in or near the center and with varying number of peripheral nonchromatinic granules attached to the nuclear membrane; chromatin in the endosome and in peri-endosomal region. The genus was established by the two Italian authors who were unaware of the existence of the genus Endamoeba. Numerous species in vertebrates and invertebrates; one species in protozoa; one species free-living. (ref. ID; 1618)

[ref. ID; 4148]
Refer "The biochemistry and Functional Morphology of the Entamoeba". (ref. ID; 4148)

  1. Entamoeba apis Fantham & Porter (ref. ID; 1618)
  2. Entamoeba aulastomi Noller (ref. ID; 1618)
  3. Entamoeba barreti Taliaferro & Holmes, 1924 (ref. ID; 164) reported year? (ref. ID; 1618)
  4. Entamoeba bovis Liebetanz (ref. ID; 1618)
  5. Entamoeba buccalis Prowazek
    See; Entamoeba gingivalis Gros (ref. ID; 1618)
  6. Entamoeba butschlii Prowazek, 1912
    See; Iodamoeba buetshlii (Prowazek, 1912) Dobell, 1919
  7. Entamoeba citelli Becker (ref. ID; 1618)
  8. Entamoeba caprae Fantham (ref. ID; 1618)
  9. Entamoeba chattoni (ref. ID; 3968)
  10. Entamoeba cobayae Walker (ref. ID; 1618)
    Syn; Entamoeba caviae Chatton (ref. ID; 1618)
  11. Entamoeba coli (Grassi) (ref. ID; 1618)
    Syn; Amoeba coli Grassi, 1879; Endamoeba coli (Grassi, 1879) Hickson, 1908
  12. Entamoeba cuniculi Brug (ref. ID; 1618)
  13. Entamoeba debliecki Nieschulz (ref. ID; 1618)
  14. Entamoeba dispar (ref. ID; 172)
  15. Entamoeba dysenteriae (ref. ID; 172)
  16. Entamoeba equi Fantham (ref. ID; 1618)
  17. Entamoeba gallinarum Tyzzer (ref. ID; 1618)
  18. Entamoeba gedoelsti Hsiung (ref. ID; 1618)
    Syn; Endamoeba intestinalis (Gedoelst) (ref. ID; 1618)
  19. Entamoeba gingivalis (Gros, 1849) (ref. ID; 1618)
    Syn; Amoeba buccalis Steinberg, 1862; Amoeba gingivalis Gros, 1849; Endamoeba gingivalis (Gros, 1849) Smith & Barrett, 1915; Entamoeba buccalis Prowazek, 1904 (ref. ID; 1618)
  20. Entamoeba histolytica Schaudinn, 1903 (ref. ID; 1618, 3968) reported author and year? (ref. ID; 172, 347, 3681, 3900, 4242)
    Syn; Amoeba coli Losch, 1875; Amoeba dysenteriae Councilman & Lafleur, 1891; Endamoeba dysenteriae Kofoid, 1920; Endamoeba histolytica (Schaudium, 1903) Hickson, 1909; Endamoeba dispar Brumpt, 1925; Endamoeba dysenteriae (Councilman & Lafleur, 1891) Craig, 1905; Entamoeba tetragena Hartmann, 1908
  21. Entamoeba invadens Geiman & Ratcliffe, 1936 (ref. ID; 164)
  22. Entamoeba invadens Rodhain (ref. ID; 1618)
  23. Entamoeba minchini Mackinnon (ref. ID; 1618)
  24. Entamoeba moshkovskii Tshalaia, 1941 (ref. ID; 1307, 1618)
  25. Entamoeba muris Grassi (ref. ID; 1618)
  26. Entamoeba nana Wenyon & O'Conner, 1917
    See; Endolimax nana (Wenyon & O'Conner, 1917) Burg, 1918
  27. Entamoeba ovis Swellengrebel (ref. ID; 1618)
  28. Entamoeba paulista (Carini) (ref. ID; 1618)
    Syn; Brumptina paulista Carini (ref. ID; 1618)
  29. Entamoeba polecki Prowazek (ref. ID; 1618)
  30. Entamoeba ranarum (Grassi) (ref. ID; 1618)
  31. Entamoeba terrapinae Sanders & Cleveland, 1930 (ref. ID; 164) reported year? (ref. ID; 1618)
  32. Entamoeba testudinis Hartmann (ref. ID; 1618)
  33. Entamoeba thomsoni Lucas (ref. ID; 1618)
  34. Entamoeba venaticum Darling (ref. ID; 1618)
  35. Entamoeba williamsi Prowazek, 1911
    See; Iodamoeba buetschlii (Prowazek, 1911) Dobell, 1919

Entamoeba apis Fantham & Porter (ref. ID; 1618)

Descriptions

In Apis mellifica; similar to E. coli. (ref. ID; 1618)

Entamoeba aulastomi Noller (ref. ID; 1618)

Descriptions

In the gut of the horse-leech, Haemopis sanguisuga; cysts with 4 nuclei. (ref. ID; 1618)

Entamoeba barreti Taliaferro & Holmes, 1924 (ref. ID; 164) reported year? (ref. ID; 1618)

Descriptions

In the colon of snapping turtle, Chelydra serpentina. (ref. ID; 1618)

Measurements

Trophozoites 14-23 (18) um long. (ref. ID; 1618)

Entamoeba bovis Liebetanz (ref. ID; 1618)

Descriptions

Uninucleate cysts; in the stomach of cattle and gnu, Connochaetes taurinus. (ref. ID; 1618)

Measurements

5-20 um in diameter; cyst 4-15 um in diameter. (ref. ID; 1618)

Entamoeba citelli Becker (ref. ID; 1618)

Descriptions

In the caecum and colon of the striped ground squirrel, Citellus tridecemlineatus; nucleus 4-6 um in diameter, with a comparatively large endosome which varies in position from central peripheral; cysts with 8 nuclei. (ref. ID; 1618)

Measurements

Rounded trophozoites 10-25 um in diameter; cysts about 15 um in diameter. (ref. ID; 1618)

Entamoeba caprae Fantham (ref. ID; 1618)

Descriptions

In goat intestine. (ref. ID; 1618)

Entamoeba cobayae Walker (ref. ID; 1618)

Synonym

Entamoeba caviae Chatton (ref. ID; 1618)

Descriptions

Similar to E. coli; in the intestine of guinea-pigs. (ref. ID; 1618)

Entamoeba coli (Grassi) (ref. ID; 1618)

Synonym

Amoeba coli Grassi, 1879; Endamoeba coli (Grassi, 1879) Hickson, 1908

Descriptions

Cytoplasm not well differentiated; movement sluggish; endoplasm granulated, contains micro-organisms and faecal debris of various sizes in food vacuoles; erythrocytes are not ingested, though in a few cases and in culture, they may be taken in as food particles; nucleus, 5-8 um in diameter, seen in vivo; compared with E. histolytica, the endosome is somewhat large (about 1 um in diameter) and located eccentrically; peripheral granules more conspicuous. The cyst spherical or often ovoid, highly refractile; immature cyst contains 1, 2 or 4 nuclei, one or more large glycogen bodies with distinct outlines, but comparatively small number of acicular, filamentous or irregular chromatoid bodies with sharply pointed extremities; when mature the cyst contains 8 nuclei and a few or no chromatoid bodies. The trophozoites and small number of cysts occur in diarrhoeic or semiformed faeces and the formed faeces contain mostly cysts. (ref. ID; 1618)

Measurements

The trophozoite 15-40 um in diameter; average individuals 20-35 um. Cyst 10-30 um in diameter. (ref. ID; 1618)

Entamoeba cuniculi Brug (ref. ID; 1618)

Descriptions

Similar to E. coli in both trophic and encysted stages; in the intestine of rabbits. (ref. ID; 1618)

Entamoeba debliecki Nieschulz (ref. ID; 1618)

Descriptions

Cysts uninucleate; in the intestine of pigs and goats. (ref. ID; 1618)

Measurements

5-10 um in diameter. (ref. ID; 1618)

Entamoeba equi Fantham (ref. ID; 1618)

Descriptions

Nucleus oval; cysts tetranucleate; seen in the faeces of horse. (ref. ID; 1618)

Measurements

40-50 by 23-29 um; cyst 15-24 um in diameter. (ref. ID; 1618)

Entamoeba gallinarum Tyzzer (ref. ID; 1618)

Descriptions

In the caeca of chicken, turkeys and possibly other fowls. (ref. ID; 1618)

Measurements

Trophozoites 9-25 (16-18) um. Cysts octonucleate 15 by 12 um. (ref. ID; 1618)

Entamoeba gedoelsti Hsiung (ref. ID; 1618)

Synonym

Endamoeba intestinalis (Gedoelst) (ref. ID; 1618)

Descriptions

In the colon and caecum of horse; endosome eccentric; bacteria-feeder. (ref. ID; 1618)

Measurements

6-13 by 6-11 um. (ref. ID; 1618)

Entamoeba gingivalis (Gros, 1849) (ref. ID; 1618)

Synonym

Amoeba buccalis Steinberg, 1862; Amoeba gingivalis Gros, 1849; Endamoeba gingivalis (Gros, 1849) Smith & Barrett, 1915; Entamoeba buccalis Prowazek, 1904 (ref. ID; 1618)

Descriptions

This amoeba lives in carious teeth, in tartar and debris accumulated around the root of teeth, and in abscesses of gums, tonsils, etc. The trophozoite is as active as that of E. histolytica; cytoplasm well differentiated; monopodal progressive movement in some individuals; endoplasm hyaline, but vacuolated, and contains ordinarily a large number of pale greenish bodies (which are probably nuclei of leucocytes, pus cells or other degenerating host cells) and bacteria in food vacuoles; nucleus, 2-4 um in diameter, appears as a ring; when stained it shows a small central endosome and small peripheral granules closely attached to the membrane. Encysted forms have not been observed in this amoeba. E. gingivalis is the very first parasitic amoeba that has become known to man. Gros (1849) found it in Russia in the tartar on the surface of the teeth. Some observers maintain that this amoeba is the cause of pyorrhoea alveolaris, but evidence for such an assumption seems to be still lacking. It has found in the healthy gums and even in false teeth. Therefore, it is generally considered as a commensal. It is widely distributed and of common occurrence. (ref. ID; 1618)

Measurements

Trophozoite 8-30 um (average 10-20 um) in diameter. (ref. ID; 1618)

Entamoeba histolytica Schaudinn, 1903 (ref. ID; 1618, 3968) reported author and year? (ref. ID; 172, 347, 3681, 3900, 4242)

Synonym

Amoeba coli Losch, 1875; Amoeba dysenteriae Councilman & Lafleur, 1891; Endamoeba dysenteriae Kofoid, 1920; Endamoeba histolytica (Schaudium, 1903) Hickson, 1909; Endamoeba dispar Brumpt, 1925; Endamoeba dysenteriae (Councilman & Lafleur, 1891) Craig, 1905; Entamoeba tetragena Hartmann, 1908

Descriptions

[ref. ID; 347]

[ref. ID; 1618]
The trophozoite is an active amoeba: Cytoplasm usually well differentiated; eruptive formation of large lobopodia, composed largely of ectoplasm; when fresh, active monopodal progressive movement; the vesicular nucleus appears in life as a ring, difficult to recognize; food vacuoles contain erythrocytes, tissue cell fragments, leucocytes, etc.; stained nucleus shows a membrane, comparatively small peripheral granules, a centrally located small endosome and an indistinct network with a few scattered chromatin granules. The trophozoite multiplies by binary fission. The amoeba lives in the lumen and in the tissues of the wall of the colon, and brings about characteristic ulceration of the colon which is typically accompanied by symptoms of amoebic dysentery. Through the portal vein, the amoeba may invade the liver in which it produces abscess, and other organs such as lung, brain, testis, etc. The infection in these organs is referred to as amoebiasis. Under certain circumstances not well understood, the amoebae remain small after division. Such amoebae are sluggish and known as the precystic forms. The precystic amoeba secretes presently a resistant wall and becomes encysted. The highly refractile cyst is spherical. At first it contains a single nucleus which divides twice. The mature cyst contains 4 nuclei. In addition the cyst contains diffused glycogen and elongated refractile rod-like bodies with rounded extremities which stain deeply with haematoxylin. These inclusions are absorbed and disappear as the cyst matures. No further changes take place in the cyst as long as it remains outside the host's intestine. The trophozoites are found in dysenteric or diarrhoeic faeces, but formed faeces usually contain cysts. The cyst is the stage by which the organism begins its life in a new host. The life-cycle of Entamoeba histolytica in human host is unknown. The amoeba has, however, been cultivated in vitro by numerous investigators since the first successful cultivation by Boeck & Drbohlav (1925). Entamoeba histolytica, is commonly known as the "the dysentery amoeba", was first definitely recognized by Losch in Russia in 1875. It is now known to be widely distributed in tropical, subtropical and temperate regions alike, although it is more prevalent in warmer regions. The serious of water-borne infection in crowded areas is easily realized when one recalls the outbreak (some 1400 cases) of amoebic dysentery and amoebiasis which originated in Chicago in 1933, where defective plumbing in certain establishments contaminated the water system with the cysts of Entamoeba histritica and the development of some 100 cases of amoebic dysentery among firemen who drank contaminated water in connection with the 1934 fire of the Union Stockyards in Chicago. Another example is the outbreak of amoebiasis among the employees of a plant as the water was contaminated with cysts. (ref. ID; 1618)

[ref. ID; 3900]

Measurements

The trophozoite 7-35 (9-20) um in diameter; cyst 5-20 um in diameter. (ref. ID; 1618)

Entamoeba invadens Rodhain (ref. ID; 1618)

Descriptions

Resembles E. histolytica; active locomotion; feed on leucocytes, liver cells, epithelial cell debris, bacteria, etc.; nucleus similar to that of E. histolytica. Cysts with one to four nuclei; glycogen vacuole; chromatoid bodies acicular, rod-like or cylindrical. Host include various reptiles. (ref. ID; 1618)

Measurements

Trophozoites 15.9 um in average diameter (9.2-38.6 by 9-30 um); cysts 13.9 (11-20) um in diameter. (ref. ID; 1618)

Entamoeba minchini Mackinnon (ref. ID; 1618)

Descriptions

In gut of tipulid larvae; cyst nuclei up to ten in number. (ref. ID; 1618)

Measurements

5-30 um in diameter. (ref. ID; 1618)

Entamoeba moshkovskii Tshalaia, 1941 (ref. ID; 1307, 1618)

Descriptions

This amoeba resembles E. histolytica, but appears to be free-living in the sewage. The organism is actively motile and assumes limacid form during locomotion. The nucleus resembles closely that of E. histolytica. No contractile vacuole occurs. Cysts are spherical, when mature it contain 4 nuclei, glycogen vacuoles and chromatoid bodies. (ref. ID; 1618)

Measurements

9-29 um or more, but commonly 11-13 um in largest diameter; cysts 7-17 um in diameter. (ref. ID; 1618)

Entamoeba muris Grassi (ref. ID; 1618)

Descriptions

In the caecum of rats and mice; cytoplasm with rod-shaped or fusiform bacteria and flagellates coinhabiting the host's organ; nucleus 3-9 um in diameter and resembles closely that of E. coli; cysts with 8 nuclei when mature. (ref. ID; 1618)

Measurements

Trophozoite 8-30 um; cysts 9-20 um in diameter. (ref. ID; 1618)

Entamoeba ovis Swellengrebel (ref. ID; 1618)

Descriptions

Cyst uninucleate; in the intestine of sheep. (ref. ID; 1618)

Entamoeba paulista (Carini) (ref. ID; 1618)

Synonym

Brumptina paulista Carini (ref. ID; 1618)

Descriptions

In the cytoplasm of many species of opalinids; cysts uninucleate. (ref. ID; 1618)

Measurements

Trophozoites 5.3-14.3 um in diameter; cysts about 9.4 um in diameter. (ref. ID; 1618)

Entamoeba polecki Prowazek (ref. ID; 1618)

Descriptions

In colon of pigs; cyst uninucleate. (ref. ID; 1618)

Measurements

10-12 um in diameter; cyst 5-11 um in diameter. (ref. ID; 1618)

Entamoeba ranarum (Grassi) (ref. ID; 1618)

Descriptions

In colon of various species of frogs; resembles E. histolytica; cysts are usually tetranucleate, but some contain as many as 16 nuclei; amoebic abscess of the liver was reported in one frog. (ref. ID; 1618)

Measurements

10-50 um in diameter. (ref. ID; 1618)

Entamoeba terrapinae Sanders & Cleveland, 1930 (ref. ID; 164) reported year? (ref. ID; 1618)

Descriptions

Cysts tetranucleate when mature; upon excystment, the cyst content divides into 4 uninucleate amoebulae; in the colon of Chrysemys elegans. (ref. ID; 1618)

Measurements

Trophozoites 10-15 um long; cysts 8-14 um in diameter. (ref. ID; 1618)

Entamoeba testudinis Hartmann (ref. ID; 1618)

Descriptions

In intestine of turtles, Testudo graeca, T. argentina, T. calcarata and Terrapene carolina. (ref. ID; 1618)

Entamoeba thomsoni Lucas (ref. ID; 1618)

Descriptions

In the colon of cockroaches; usually attached to debris by a knob-like process, highly adhesive; cytoplasm poorly differentiated; vesicular nucleus with peripheral granules; endosome variable, with loosely aggregated granules and a central dot; cyst with one to four nuclei. (ref. ID; 1618)

Measurements

Rounded form 7-30 (15-25) um in diameter; cysts 8-16 um in diameter. (ref. ID; 1618)

Entamoeba venaticum Darling (ref. ID; 1618)

Descriptions

In the colon of dog; similar to E. histolytica; since the dog is experimentally infected with the latter, this amoeba discovered from spontaneous amoebic dysentery cases of dogs, in one of which were noted abscesses of liver, is probably E. histolytica. (ref. ID; 1618)