A DISEASE OVERVIEW
Trichomoniasis is the most common, non-viral sexually transmitted
disease (STD) in the world [1,
2]. Infection is caused by the protozoan Trichomonas
vaginalis (Trichomonas) and overt symptoms
are recognized in approximately 50% of infected women. US
incidence is estimated at 5 to 8 million cases per year
[3-5], and with worldwide incidence estimates ranging from
170 to 350 million cases per year (see Figure 1) [6-8].
Precise estimates are hampered by the poor efficacy of diagnosis
the variability in symptomology, and the poor reporting
rates for Trichomonas infection, which is among the lowest
for all STDs. Accordingly, Trichomonas infection rates in
the US and elsewhere may be considerably higher than previously
Methods For Diagnosing Trichomonas Infection Are Inadequate
Trichomonas infection in women leads to vaginitis and may
contribute to 30% of all vaginitis cases (10 to 20 million/year
US). However, it is commonly mistaken for either a yeast
or bacterial infection, the two other main causes of vaginitis
Part of the problem in diagnosing Trichomonas infection
is that the symptomology varies widely: up to 50% of women
may be misdiagnosed. Trichomonas infection, unlike many
STDs cannot be consistently inferred from the clinical presentation.
Although some manifestations of the disease, such as strawberry
cervix, have a very high correlation with infection.
Most patients do not have this symptom. Indeed, none of
the commonly associated symptoms of Trichomonas infection
(i.e. yellow, frothy, or purulent vaginal discharge, puritus,
odor, pelvic inflammation, abdominal pain, and strawberry
cervix) can be relied upon to define Trichomonas infection.
Therefore, diagnosis must be made upon the detection of
live, motile organisms through direct microscopic examination
of a vaginal sample or by culturing the organism .
Wet mount microscopy is the most common method of diagnosis,
but requires trained observers and access to a microscope.
Even in expert hands this technique is found to be only
58% sensitive .
The other major diagnostic method, detection of the organism
in culture, is considered more accurate than microscopy.
However, it takes 2 to 5 days to obtain culture results,
and culture also requires specialized laboratory equipment.
Moreover, culture is still only 68% sensitive 
and cannot be performed from urine samples .
Culture also has the major drawback of delaying the time
to treatment by several days. During this interval the infection
can be spread to others and the patient continues to suffer.
Diagnosis Contributes To The Low Rates Of Treatment And
A Sustained Disease Burden
Failure to return for therapy when the patient must wait
for test results is a major problem with all STD diagnoses.
The lack of accurate point of care diagnosis for Trichomonas
infection results in a situation where up to 50% of the
women are misdiagnosed and subsequently mistreated. This
leads to additional doctor visits, high rates of patient
dropout, and low rates of successful treatment.
This imposes a tremendous economic burden on society. Without
treatment, infection in women is non-self-limiting. Infection
has serious health consequences. Men, who typically suffer
from a shorter duration of infection than women (approximately
two weeks to four months), are almost never diagnosed yet
can easily transmit the parasite to women [14,15].
Infection Can Be Easily And Effectively Treated At Low Cost
If Accurately Diagnosed
Unlike other causes of vaginitis, Trichomonas is an STD,
and so both partners should be treated for infection. Currently,
Flagyl (metronizadole) is the only treatment available in
the US and is effective after treatment [16-17].
However, given the potentially serious side effects of this
drug, treatment for suspected Trichomoniasis is not necessarily
recommended. Better diagnostic accuracy would help to prevent
the unnecessary use of Flagyl, an important factor considering
that increasing numbers of Flagyl-resistant Trichomonas
infections are being reported.
To Treat Trichomonas Infection Can Have Serious Health Consequences
For Women and Men
As is the case for other chronic sexually transmitted infections
(i.e. Chlamydia), an increasing amount of evidence suggests
that Trichomonas infection can have many secondary adverse
health consequences. A particularly serious aspect of Trichomonas
infection in women is an increased susceptibility to HIV
infection . The correlation between Trichomoniasis and
increased risk of acquiring HIV has now been established.
Trichomonas vaginalis is one of the most important
cofactors in amplifying HIV transmission. The pathology
induced by T. vaginalis during co-infection with
HIV can increase HIV shedding .
Trichomonas infection appears to also act to expand the
portal of entry for HIV in an HIV-negative person. Importantly,
symptomatic men with Trichomoniasis increase HIV viral load
in semen .
Without a doubt, accurate diagnosis and treatment of Trichomoniasis
reduces the potential for HIV infection among susceptible
In addition, Trichomonas infection - a chronic disease that
can persist indefinitely in women - is associated with an
increased risk of cervical cancer [23-30].
Cervical cancer is a leading cause of death in women worldwide,
and is known to result from infection by Human Papilloma
Virus (HPV). The relationship of Trichomonas infection (which
unlike HPV is treatable) to cervical cancer is an area of
intense clinical interest worldwide.
Furthermore, Trichomonas infection is also being increasingly
recognized for its impact on reproduction success and pregnancy
outcomes. It is estimated that 25% of pregnant women in
some populations are infected with Trichomonas, in part
due to the overlapping demographics of infection risk and
reproductive age, both of which tend to be concentrated
in the 18-30 year age group. Trichomonas infection is associated
with an increased risk of adverse events occurring both
during and after the pregnancy and therefore, an increased
demand for pre- and postnatal care [6,
Moreover, infection with Trichomonas can reduce the chances
of conception, a factor not often considered for the millions
of women seeking fertility treatment [32-34].