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46 CHAPTER 3

though large numbers of organisms are present in the known cyst stage associated with its life cycle. T. hominis
vaginal discharges. Men are usually asymptomatic and exhibits an undulating membrane as does T. vaginalis.
serve as carriers, but may develop a milky discharge and Differentiating between the two nonpathogenic species,
a nonspecific urethritis. Trichomonas tenax, which is found in the human mouth,
and T. hominis, which is found in the intestine, may be
Disease Transmission necessary in some cases but both are considered harmless
commensal parasites. Rare cases of pulmonary trichomo-
Symptoms range from mild to none at all. Women in niasis have been documented medically and a few cases

particular may be asymptomatic but are capable of trans- of trichomonalempyema (inflammation with body fluids
mitting the organism to others. The condition is quite often found between the pleura) have been reported.

contagious and both partners in a sexual relationship Only T. tenax will be covered here, as it may be
should be treated, as reinfection may occur on a regular necessary to differentiate between T. vaginalis and
basis when one partner is asymptomatic. T. tenax.

Laboratory Diagnosis
TRICHOMONAS TENAX
The diagnosis of infection by T. vaginalis is accomplished
T. tenax is primarily found in the mouth and for this rea-
by direct observation of motile trophozoites. Because the son it may be necessary to determine the presence of and
organisms may be mistaken for white blood cells, the
identification of the organism. The T. tenax organism is
sample should be immediately examined upon receipt of considered a harmless commensal and is frequently found
the sample. All body fluids, including urine, vaginal dis-
in the tartar (plaque) that has hardened around the teeth.
charges, or urethral secretions, should not be allowed to
cool before examination occurs. A liquid microbiological
media is sometimes used to culture the organism and per- Morphology
manent stained slides are possible but yield a number of
false positive and false negative results. Some serological The trophozoite of T. tenax is similar to other
tests are available but are not widely used. trichomonads, particularly when compared with
T. hominis, with the exception that it is more slender.
This organism ranges in size from 5 to 11 μm in length
Treatment and Prevention and 7 to 10 μm in width. T. tenax has five flagella from
the anterior end, with four extending to the anterior por-
The medication of choice is metronidazole. Prevention is
accomplished by the avoidance of unprotected sex with tion of the organism and one to the posterior. An undulat-
ing membrane runs the length of the trophozoite as does
partners whose history is not known. Prompt treatment
and diagnosis of men who are asymptomatic and who T. hominis. Stained specimens will yield a pear-shaped
cell with an axostyle, a centrally located line extending vir-
may readily transmit the organism is important.
tually throughout the length of the organism. One nucleus
is generally visible at the anterior end, and the size is the
NONPATHOGENIC FLAGELLATES general range for the smaller white blood cells, so it is easy
OF THE DIGESTIVE SYSTEM to miss T. tenax as easily as T. vaginalis, especially for an
(T. HOMINIS, T. TENAX) older specimen where the motility has decreased.
It is important to distinguish pathogenic from non- Symptoms
pathogenic flagellates. Perhaps the most common of
these nonpathogenic organisms is that of Trichomonas T. tenax may find crevices in the gingiva, the gum tissue
hominis. T. hominis is small and is usually not found or that surrounds the neck of the teeth. Generalized inflam-
identified from stool specimens due to the concentration mation may occur and is most prevalent in smokers and
of bacteria and undigested materials in the fecal speci- those with poor dental hygiene. The condition is pre-
men. T. hominis is found as a trophozoite and has no dominantly asymptomatic, however.