Volume s1-24, Issue 1
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



Morphologically, the three species of of man are distinct, although and resemble each other more than either resembles is much the larger, the other two being about the same length. is more robust in shape and is more slender.

and normally have a single compound blepharoplast which may occasionally appear as two approximately equal elements. In there are characteristically two blepharoplasts of unequal size, the smaller being ventral in position. The oral and vaginal species have regularly four anterior flagella. has a variable number, usually four or five, but more characteristically five. One of these is attached to the smaller ventral blepharoplast and the other four to the larger one.

The undulating membrane of is relatively longer than that of , although typically less than body length in both and without an extension of the marginal filament into a trailing flagellum. has a full-length undulating membrane with a trailing flagellum. At the margin of the undulating membrane each of the three species has an accessory filament which is more slender than the posterior flagellum.

The costa of and is very slender and of uniform diameter while that of is coarser, and thicker in its midregion. Both and have a well-developed parabasal apparatus, but this is apparently absent in . The axostyle of is relatively somewhat coarser than that of the other two species. In large individuals of it tends to split into a number of fibrils.

The nucleus of is typically much elongated while in the other two species it is more commonly rounded or oval. In and the chromatin is usually aggregated into granules which are uniformly distributed; these are larger and fewer in . In the chromatin is less often aggregated into granules and commonly forms a layer against the nuclear membrane.

The siderophilic cytoplasmic granules of are numerous and scattered through the cytoplasm but tend to collect along the axostyle and costa. In they are fewer, forming a row along the costa but not along the axostyle. In there is a row of paracostal granules at the base of the undulating membrane and a zone of perinuclear granules or a chromatic cloud in the vicinity of the nucleus.

The cytostome is inconspicuous in but more evident in the other two species, especially in . In fresh material usually shows no food inclusions except a leukocyte in an occasional individual while usually shows a variety of food bodies.

forms pseudopodia more often than the other two species, is more sluggish, and shows greater tendency to adhere to solid objects and to each other at the posterior ends.

Survey data show that and are much more prevalent than even in the same group of persons, indicating that the latter species is not transferable to other parts of the body.

Available literature provides abundant evidence that, in the matters of culture conditions, inoculation into various animals and unsuccessful transmission of intestinal and oral trichomonads to the human vagina, these three species are physiologically as well as morphologically distinct.

Donné is the type species of the genus and presents no taxonomic problem. (O.F.M.) has priority for the oral species. The intestinal form appears to have a variable number of flagella, characteristically five. For the present, (Davaine) is retained for it. Cleveland is shown to be distinct from and very similar to, if not identical with, a species from the intestine of frogs and toads.


Article metrics loading...

The graphs shown below represent data from March 2017
Loading full text...

Full text loading...

  • Received : 16 Aug 1943

Most Cited This Month

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error