The Past, Present, and Future in the Diagnosis of a Neglected Sexually Transmitted Infection: Trichomoniasis

More than one million curable sexually transmitted infections occur every day. Trichomonas vaginalis is one of the main infections responsible for these epidemiological data; however, the diagnosis of this protozoan is still mainly based on microscopic and culture identification. The commercialization of immunological tests and the development of molecular techniques have improved the sensitivity of classical methods. Nevertheless, the fact that trichomoniasis is a neglected parasitic infection hinders the development of novel techniques and their implementation in routine diagnosis. This review article shows the different methods developed to identify T. vaginalis in population and the difficulties in diagnosing male and asymptomatic patients. The importance of including this parasite in routine gynecological screening, especially in pregnant women, and the importance of considering T. vaginalis as an indicator of high-risk sexual behavior are also discussed.

Evaluation of microscopy and PCR for detection of Dientamoeba fragilis

Introduction

Dientamoeba fragilis (D. fragilis) diagnosis is an intestinal protozoan parasite globally found in rural and urban areas and is attracting a growing interest. Its prevalence in stool varies from 0.2% to more than 19% depending upon the population studied.

Materials and Methods

This study was based on the examination of 100 stool samples of randomly referred cases in a rural area in Motobus district, Kafr El-Sheikh governorate, Egypt. Our aim was to investigate the presence of D. fragilis in stool of the examined individuals using conventional polymerase chain reaction (PCR) compared to wet mount and trichrome stain with confirmation of infection by transmission electron microscopy.

Results

D. fragilis was detected in 13/100 of the stool samples examined using wet mount smears, while trichrome stain detected 17/100. Conventional PCR diagnosed 41 cases of D. fragilis in the studied group. A very good agreement was found between wet mount and trichrome stain for diagnosing D. fragilis, while there was fair agreement between conventional PCR and both microscopy methods. Transmission electron microscope was performed on pooled positive samples that revealed the internal structures of D. fragilis trophozoite with its characteristic nucleus.

Conclusions

PCR technique was superior to microscopy for the detection of D. fragilis. Trichrome stain remains vital for microscopic diagnosis.

Comparison of Molecular and Parasitological Methods for Diagnosis of Human Trichostrongylosis

Human trichostrongyliasis is a zoonotic disease that is prevalent among rural populations in some countries. This study was performed to evaluate various parasitological methods and polymerase chain reaction (PCR) for the diagnosis of human trichostrongyliasis. A total of 206 fresh stool samples were collected from residents of endemic villages of Northern Iran. All samples were examined using conventional parasitological methods, including wet mount, formalin ethyl acetate concentration (FEAC), agar plate culture (APC), Harada-Mori culture (HMC), and Willis, along with the PCR technique. Among the total of 206 individuals examined, 72 people (35%) were found infected with Trichostrongylus species using combined parasitological methods. By considering the combined results of parasitological methods as the diagnostic gold standard, the Willis technique had a sensitivity of 91.7% compared with 52.8% for the APC, 40.3% for the HMC, 37.5% for FEAC, and 5.6% for the wet mount technique. The diagnostic specificity of all the parasitological methods was 100%. Furthermore, the PCR method detected Trichostrongylus spp. DNA in 79 fecal samples (38.3%) with a sensitivity of 97.2% and a specificity of 93.3%. According to the current findings, the Willis method was more sensitive than are the other parasitological methods in the diagnosis of human trichostrongyliasis. However, the PCR assay was more sensitive and more reliable in the detection of human trichostrongyliasis in comparison with the parasitological methods.

Prevalence, clinical features, and diagnosis of Trichomonas vaginalis among female STI clinic attendees in Trinidad

Background

Trichomonas vaginalis (TV) is one of the most common pathogens causing sexually transmitted infections (STIs) in both men and women. Since there are no accurate prevalence data available on TV infection among women for Trinidad and Tobago and in the Caribbean region, there is a great need for research to study the dynamics of the infection and its transmission.

Objectives

To determine the prevalence and diagnose TV infection in women attending the STI clinic and to provide recommendations for control and prevention of trichomoniasis in the community.

Study Design

A cross-sectional study was designed after obtaining the informed consent. Following a routine clinical examination, vaginal swabs were collected - one for wet mount preparation, one for InPouch culture, and other two for OSOM rapid test/and fluorescent antibody testing. Cotton swabs and Dacron swabs were used for testing.

Results

A prevalence of 16% of trichomoniasis out of 422 females was recorded. In all, 65 (65%) were in the age range of 15-29 years and peak of 30% in the age group of 20-24 years. Vaginal discharge was a common complaint (83%); 75.6% had foul odor and only 9.8% had typical fishy odor. The majority of them (87%) had whitish-yellow colored discharge.

Conclusion

Prevalence of trichomoniasis is significant in the female population attending STI clinic. Targeting high-risk age group between 15 and 29 years for control and prevention would be beneficial. Prompt and accurate diagnosis using appropriate laboratory test is recommended.

Trichomoniasis: How do we diagnose in a resource poor setting?

BACKGROUND

Diagnosis of Trichomonas vaginalis vaginalis infection based solely on clinical symptoms and signs is unreliable because the spectrum of infection is broad and other sexually transmitted pathogens cause similar signs and symptoms.

AIMS

Our study was undertaken to study the frequency of T. vaginalis infection in women presenting with vaginal discharge, to characterize the clinical features, and to study the sensitivity and specificity of microbiological investigations in the diagnosis of the same.

MATERIALS AND METHODS

This was a hospital-based descriptive study done on 400 female patients with vaginal discharge attending the Gynecology out-patient department (OPD) of JIPMER, Puducherry, from May 2010 to July 2011. Women of age between 20 years and 50 years presenting with vaginal discharge irrespective of marital status, were included, and detailed history was elicited and thorough examination was performed.

RESULTS

In 400 women presenting with vaginal discharge from Gynecology out-patient department (OPD) included in the study, T. vaginalis infection was found in 27 (6.75%) women. The risk factors for trichomoniasis included history of pre- or extramarital sexual contact in the woman or her partner, symptomatic partner, and alcohol consumption. A positive association with pelvic inflammatory disease was also observed. The most frequent symptoms included lower abdominal pain, dysuria, and dyspareunia. Combining of Whiff test, pH > 4.5, and pus cells in Gram-stained smear, the specificity in diagnosing the infection (97.3%) approached that of the reference standard, i.e., culture. On combining wet mount with Papanicolaou smear, the sensitivity increased to 92.6%, which was higher than that individually done.

CONCLUSION

To conclude, diagnosis of T. vaginalis infection based solely on clinical symptoms and signs is unreliable, and combination of simple laboratory tests increases the diagnostic performance close to the reference standard (culture), especially in resource poor settings.