Asymptomatic non-ulcerative genital tract infections in a rural Ugandan population.
OBJECTIVE: To document the prevalence of asymptomatic non-ulcerative genital tract infections (GTI) in a rural African cohort. METHODS: The study population consisted of all adults aged 15-59 residing in 56 rural communities of Rakai District, southwest Uganda, enrolled in the Rakai STD Control for AIDS Prevention Study. Participants were interviewed about the occurrence of vaginal or urethral discharge and frequent or painful urination in the previous 6 months. Respondents were asked to provide blood and a first catch urine sample. Serum was tested for HIV-1. Urine was tested with ligase chain reaction (LCR) for N gonorrhoeae and C trachomatis. Women provided two self administered vaginal swabs; one for T vaginalis culture and the other for a Gram stained slide for bacterial vaginosis (BV) diagnosis. RESULTS: A total of 12,827 men and women were enrolled. Among 5140 men providing specimens, 0.9% had gonorrhoea and 2.1% had chlamydia. Among 6356 women, 1.5% had gonorrhoea, 2.4% had chlamydia, 23.8% were infected with trichomonas and 50.9% had BV.53% of men and 66% of women with gonorrhoea did not report genital discharge or dysuria at anytime within the previous 6 months. 92% of men and 76% of women with chlamydia and over 80% of women with trichomonas or BV were asymptomatic. The sensitivities of dysuria or urethral discharge for detection of infection with either gonorrhoea or chlamydia among men were only 21.4% and 9.8% respectively; similarly, among women the sensitivity of dysuria was 21.0% while that of vaginal discharge was 11.6%. For trichomonas or BV the sensitivity of dysuria was 11.7% and that of vaginal discharge was 10.5%. CONCLUSION: The prevalence of non-ulcerative GTIs is very high in this rural African population and the majority are asymptomatic. Reliance on reported symptoms alone would have missed 80% of men and 72% of women with either gonorrhoea or chlamydia, and over 80% of women with trichomonas or BV. To achieve STD control in this and similar populations public health programmes must target asymptomatic infections. (+info)
Diagnosis of trichomoniasis by polymerase chain reaction.
The clinical usefulness of polymerase chain reaction (PCR) for the diagnosis of trichomoniasis was evaluated in comparison with other conventional tests. PCR was used for specific detection of Trichomonas vaginalis by primers based on the repetitive sequence cloned from T. vaginalis (TV-E650). Between June 1996 and August 1997, 426 patients visited the department of obstetrics and gynecology, Hanyang University Kuri Hospital and were examined for trichomoniasis using wet mount examination, Papanicolaou (Pap) smear, culture and PCR. One hundred and seventy-seven patients (group A) visited with the symptoms of vaginal discharge and 249 patients (group B) visited for regular cervical Pap smear with no vaginal symptoms. From group A (n = 177), 3 infections (2.0%) were detected by wet mount, 6 infections (3.3%) by Pap smear and culture, and 17 infections (10.4%) by PCR. From group B (n = 249), 4 patients (1.6%) were found to have T. vaginalis by culture and 6 infections (2.4%) were detected by PCR. Therefore, in both groups, PCR for T. vaginalis showed a higher detection rate compared with conventional wet mount, Pap smear or culture. The detection by PCR was specific for T. vaginalis since no amplification was detected with DNAs from other protozoa and Candida albicans. The sensitivity and specificity of PCR were 100%. This method could detect T. vaginalis in vaginal discharge at a concentration as low as 1 cell per PCR mixture. These results indicate that PCR could be used as a specific and sensitive diagnostic tool for human trichomoniasis. (+info)
Delayed versus immediate bedside inoculation of culture media for diagnosis of vaginal trichomonosis.
A comparison of delayed versus immediate inoculation of culture medium for the diagnosis of trichomonosis was conducted. The sensitivities of the two methods were 100 and 97.4%, respectively. Delayed inoculation of culture medium for women without evidence of trichomonosis on direct microscopic examination is a valid diagnostic procedure. (+info)
Identification of Trichomonas vaginalis alpha-actinin as the most common immunogen recognized by sera of women exposed to the parasite.
A study on presence of antibodies to Trichomonis vaginalis in serum was done on a group of 500 pregnant, asymptomatic Angolan women. A serologic screening, done by ELISA, revealed that 41% of the women had IgG and IgM against the parasite. Analysis of sera by immunoblotting revealed that 94.4% of sera with anti-T. vaginalis IgG class antibodies were reactive against a common immunogenic protein of 115 kDa. The common immunogen was identified as the protozoan alpha-actinin. All sera recognizing the 115-kDa antigen were reactive against both native and recombinant T. vaginalis alpha-actinin and nonreactive against human alpha-actinin. The findings presented in this work offer a new tool for epidemiologic studies and open new perspectives for vaccination. (+info)
Viability of Trichomonas vaginalis in transport medium.
The ability of Amies gel agar transport medium to maintain the viability of Trichomonas vaginalis was determined by comparing transported vaginal specimens to specimens immediately inoculated into culture medium. The prevalence of trichomonosis in the study population was 26% (68 of 260 women). The immediate inoculation method detected infections in 64 of 68 infected women (sensitivity of 94.1%). The transport method detected 62 of 68 infections (sensitivity of 91.2%). There was no significant difference between the two methods. (+info)
Trichomonas vaginalis interactions with fibronectin and laminin.
The sexually transmitted protozoan Trichomonas vaginalis cytoadheres to vaginal epithelial cells and causes contact-dependent cytotoxicity which, when combined with the normal exfoliation process, leads to erosion of the epithelium, which may allow trichomonads into extracellular matrix and basement membrane sites. Therefore, the association of T. vaginalis with immobilized fibronectin (FN) and laminin (LM) on cover-slips was examined. Binding of live parasites to coated cover-slips was time- and parasite-density-dependent. Coincubation with an inhibitor of trichomonad cysteine proteinases resulted in an increased attachment of parasites to FN but had no effect on binding to LM, denoting that protease activity influenced optimal FN associations. Further, 20 h mid-exponential phase trichomonads placed in fresh culture medium for 3 h gave higher levels of binding to FN, suggesting that changes during growth in vitro to T. vaginalis organisms affect maximal levels of binding to FN. Extended incubation with substrates diminished the capacity of parasites to bind FN and LM. Treatment of live organisms with periodate reduced binding to LM but not FN, suggesting a role for carbohydrates. In addition, trypsinization of live parasites decreased numbers bound to both substrates. Placement of trypsinized parasites in medium for 2 h fully regenerated binding to FN but not LM. Incubation of trypsinized parasites with cycloheximide abrogated regeneration of attachment to FN, affirming a role for synthesized surface proteins in FN binding. Importantly, the T. vaginalis adhesin proteins that mediate cytoadherence, and iron, a factor that regulates adhesin synthesis, were not involved in FN and LM recognition. These results suggest a role for surface proteins and carbohydrates in trichomonal associations with FN and LM, respectively. (+info)
Improved diagnosis of Trichomonas vaginalis infection by PCR using vaginal swabs and urine specimens compared to diagnosis by wet mount microscopy, culture, and fluorescent staining.
Four vaginal cotton swab specimens were obtained from each of 804 women visiting the outpatient sexually transmitted disease clinic of the Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands, for validation of various forms of Trichomonas vaginalis diagnostic procedures. One swab specimen was immediately examined by wet mount microscopy, a second swab was placed in Kupferberg's Trichosel medium for cultivation, and two swabs were placed in phosphate-buffered saline (PBS), pH 7.2. The resulting PBS suspension was used for direct staining with acridine orange and fluorescence microscopy, inoculation of modified Diamond's culture medium, and a PCR specific for T. vaginalis. A total of 70 samples positive in one or more of the tests were identified: 31 (3.8%) infections were detected by wet mount microscopy, and 36 (4.4%) were identified by acridine orange staining, as opposed to 40 (4.9%) and 46 (5.7%) positives in modified Diamond's and Trichosel media, respectively. PCR was positive for 61 (7.5%) samples. Secondly, from each of 200 women were obtained a urine sample and a vaginal cotton swab specimen, and 200 urine samples were obtained from men. For the women, 15 (7.4%) of the samples showed a positive result for either the wet mount (n = 1), Trichosel culture (n = 6), PCR on the vaginal swab sample (n = 10), or PCR on the urine specimen (n = 11). Four men (2%) were diagnosed with a T. vaginalis infection. Thus, PCR appears to be the method of choice for the detection of genital infections with T. vaginalis. (+info)
Trichomonad invasion of the mucous layer requires adhesins, mucinases, and motility.
BACKGROUND/OBJECTIVE: Trichomonas vaginalis, the causal agent of trichomonosis, is a flagellated parasitic protozoan that colonises the epithelial cells of the human urogenital tract. The ability of T vaginalis to colonise this site is in part a function of its ability to circumvent a series of non-specific host defences including the mucous layer covering epithelial cells at the site of infection. Mucin, the framework molecule of mucus, forms a lattice structure that serves as a formidable physical barrier to microbial invasion. The mechanism by which trichomonads traverse the mucous covering is unknown. Proteolytic degradation of mucin, however, may provide for a mechanism to penetrate this layer. The goal, therefore, was to determine how trichomonads cross through a mucous layer. METHODS: Secreted trichomonad proteinases were analysed for mucinase activity by mucin substrate-sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The importance of trichomonad mucinases for traversing the mucous layer was examined on an artificial mucin layer in invasion chambers. Adherence to mucin and tissue culture cells was measured using a microtitre plate assay. RESULTS: Trichomonad isolate 24402 secreted five proteinases when incubated in PBS. All five proteinases were shown to possess mucinase activity. These mucinases were able to degrade bovine submaxillary mucin and to a lesser extent porcine stomach mucin. These enzymes were active over a pH range of 4.5-7.0 and were inhibited with cysteine proteinase inhibitors. Furthermore, T vaginalis was shown to bind to mucin possibly via a lectin-like adhesin. Adherence to mucin was increased threefold when parasites were grown in iron deficient medium. Adherence to soluble mucin prevented attachment to HeLa cells. Proteinase activity, adherence, and motility were required for trichomonads to traverse a mucin layer in vitro. CONCLUSIONS: These results show that trichomonads can traverse the mucous barrier first by binding mucin followed by its proteolytic degradation. The data further underscore the importance of trichomonad proteinases in the pathogenesis of trichomonosis. Finally, this study suggests that interference with trichomonad mucin receptors and proteinases may be a strategy to prevent colonisation by this parasite. (+info)