Trichomoniasis is the most common non-fatal chronic sexually transmitted infection in the world, with 276 million new cases occurring each year. The condition is caused by the flagellated parasite Trichomonas vaginalis. It is considered a neglected disease without epidemiological surveillance, despite being a public health problem as 85 percent of its cases are asymptomatic
In Mexico, about 100,000 new cases are reported annually, an underestimated figure because most people infected do not present symptoms, and they stop going to the doctor for treatment, so the infection continues to spread among the sexually active population.
To cope with this condition, the Rossana Arroyo Verástegui research group, attached to the Department of Infectomics and Molecular Pathogenesis of CINVESTAV, focuses on the analysis of the mechanisms of action of the parasite that cause a chronic infection.
“We focus on the identification and characterization of parasite molecules: adhesins, receptors, proteases and inhibitors that participate in the processes of adhesion, cytotoxicity and hemolysis (destruction of erythrocytes), among others,” explained Arroyo Verástegui.
In particular, they work on the implementation of a new diagnostic method for trichomoniasis, using blood samples instead of vaginal secretions. The blood immunodiagnostic kit has been tested in more than 2,000 samples of patients with vaginitis. It was also validated in vitro studies and by molecular methods by amplification of the parasite’s DNA sequences. After applying treatment the volunteers were sampled again and in most cases the infection was negative.
The results are promising because its efficiency is similar to that of molecular methods that use vaginal samples. In Mexico these tests are not applied on a regular basis, the infection is detected with direct observation under a microscope or accidentally in urine tests. The difference is that the kit uses blood samples to obtain a serum sample (between 3 and 5 milliliters), is less invasive, more economical, for mass use and detects active infection.
The design of this diagnostic method is based on the human humoral immune response during trichomoniasis, through the antibodies produced against some of the parasite molecules, which disappear after treatment. To date, some molecules of the microorganism have been identified as targets for the immunodiagnostic in blood of trichomoniasis. The proposal detects anti-ticomonas antibodies in the patient’s blood using their own molecules as decoy.
In addition, the researchers study the parasite’s response to changes in iron and glucose levels during infection, its impact and differential modulation of virulence mechanisms due to the alteration in the molecules that participate in them. Also, they have identified one of the regulatory mechanisms that modulates the amount of parasite molecules in response to iron variations.
In the therapeutic part, in collaboration with the Metropolitan Autonomous University (UAM) and the National Polytechnic Institute (IPN), the CINVESTAV researchers participate in the identification of new tricomonicidal compounds, as an alternative treatment. The group has focused on the identification of the mechanism of action of these compounds in the parasite and the results are promising.
Trichomonas vaginalis colonises the urogenital tract of women and men and interacts with vaginal, cervical, urethral, and prostate cells. Eighty-five percent of cases of trichomoniasis are asymptomatic, but when symptoms occur, it manifests with a purulent vaginal or urethral discharge of a yellowish-green colour and purulent type; vulvar and vaginal erythema; dysuria pruritus (itching); pain in the belly or back; and pain during sexual intercourse, vaginitis, urethritis, chronic non-gonococcal prostatitis, balanoposthitis or epididymitis.
Trichomoniasis causes health problems such as: vaginal or cervical inflammation; posthysterectomy infection; infertility in both sexes; and atypical pelvic inflammation. In addition, during pregnancy increases the risk of premature delivery; births with low weight, and cognitive problems. It also has a higher susceptibility to AIDS infection, by increasing the population of lymphocytes in the urogenital tract and producing molecules that degrade antimicrobial and immunoregulatory peptides.
Trichomoniasis is curable, so a good diagnosis would allow the establishment of an adequate treatment, with which new cases of AIDS could be reduced up to 20 percent and the consequences caused by the infection would be reduced. “Hence the relevance of having accurate, efficient, economical and easily accessible diagnostic methods for the entire sexually active population,” said Rossana Arroyo Verástegui.
Source: Conexion Cinvestav