Kawther Abdul-Hussein Mahdi Al-Mussawi
Department of Biology, College of Education for Pure Sciences.
Trichomonas vaginalis is a flagellate, anaerobic, single-celled belong to protozoa that infects the genital-urinary tract of humans, as it invades vagina, cervix, and urinary system in women and the bladder, seminal vesicle and prostate in men. Therefore, it is considered a sexually transmitted diseases (STDs), and the symptoms caused by the parasite are more pronounced in women.
Trichomonas vaginalis belong to eukaryotes and is considered an obligate parasite because cannot synthesize many of the macromolecules important for life, such as purines, pyrimidine, and lipids. It obtain these substances from vaginal secretions or from phagocytizing host cells or existing bacteria. The preferred pH of the parasite ranges from 6-6.3, However, it tolerates a spectrum of acidity changes (1).
Parasite obtains iron from lactoferrin present in the vaginal mucosa or from erythrocytes . Infection in Trichomonas vaginalis is characterized by a number of clinical signs, including greenish-yellow vaginal discharge with a foul odor, peeling of epithelial cells, and a change in the pH of the vagina(2). These symptoms are divided depending on the stage of infection, as the acute stage is characterized by abundant vuluitis with blood spots in the mucous membrane, while the chronic stage is characterized by moderate symptoms and secretions of mucus, which represents the spreading stage of the infection(3).
Parasite infects both sexes. Infection with this parasite results in serious consequences for women, including infertility and cervical cancer(4). In pregnant women, infection leads to miscarriage or rupture of the placental membranes before delivery, which leads to premature birth and low birth weight. As for men, the infection is without symptoms and if there are symptoms, then it is urethritis with slight itching in the urethra and simple secretions with urine and epididymitis and prostatitis (5) and this is due to the nature of the male reproductive tract and its containment of zinc, so the male canal is a toxic nature to the parasite (6).
Virulence factors:
1-Cysteine proteinases : Studies have found that parasite is rich in cysteine proteinases ( Cps) that are secreted from the surface of the parasite and work to break down the host’s immune proteins, They also contribute to causing infection (7), and they have a role in acquiring food for the parasite, facilitating the process of adhesion to the host’s cells, and contribute to the parasite’s evasion and the host’s immune escape (8).
2-Adhesion proteins: There are five types of adhesion factors present on the outer surface of parasite, which represent surface proteins that play an important role in adhering to the host’s cells, namely AP51,AP23,AP65, AP33, AP120 (9). These adhesive proteins communicate with the host’s cells through special receptors. When adhesion the parasite begins to transform into the amoeboid form, and the amount of these adhesive proteins increases by increasing high concentrations of iron, and as a result, the virulence of the parasite increases (10).
3-Hemolysis: The parasite analyzes erythrocytes to obtain biomolecules such as fats because the parasite lacks the mechanisms to synthesize these molecules. Therefore, the severity of the infection increases during menstruation due to the increase in nutrients available to the parasite.
4-Cell detaching factor: It is a glycoprotein with a molecular weight of 200 kilo Dalton that causes detachment of one layer of vaginal epithelial cells, causing the parasite to penetrate and cause infection (11).
Methods of laboratory diagnosis:
1-Microscopic examination: This method is considered one of the traditional laboratory methods used to diagnose the parasite based on the distinctive vibrating movement of the parasite resulting from the flagella and the undulating membrane (12), but sometimes the flagella may be lost during the preparation of the slides, so the shape of the parasite becomes similar to pus cells and it is difficult to diagnose it. However, the importance of this method lies in its speed so the patient was able to take the treatment from the first visit to the doctor but the sensitivity of this method ranges between %, so it cannot be relied upon alone .
2-Staining method: There are several types of dyes used to stain the parasite, such as Acridin orange dye, Giemsa stain, and Hematoxylin stain, but the efficiency of these dyes varies among them, in addition to the lack of accuracy, as the fixation process leads to the parasite losing its distinctive movement (13).
3-Culture method: Method of cultivation in special culture media for the parasite as a Diamond medium, Kupferberg medium, modified Diamond medium and In pouch Tv medium under conditions of little ventilation is a standard method for diagnosing the parasite, as its efficiency ranges from 85-95 % and requires 300-500 parasite, incubation period of 2-7days, temperature 35-37 and pH 6-6.5, as well as a number of nutrients and antibiotics to protect from contamination with other organisms (14) and the sensitivity reaches to 100 %, but it is not used in the daily work of laboratories because it requires a long period of incubation and its high cost (15).
4-Immunological method: Various immunological methods are used, including Latex agglutination test, Complement fixation test, Immunofluorescence test and Enzyme-linked immunosorbent assay
( ELISA) to obtain the best results and the lowest percentage of errors to diagnose the parasite. However, these methods have a number of disadvantages, as in some cases it is not possible for these methods to detect antibodies if their concentration is low ( 16).
5-Molecular methods: It is one of the best techniques used to diagnose organisms, whether cultivable or non-cultivable (17) including a polymerase chain reaction ( PCR) technique that relies on amplifying pieces of the parasite’s DNA millions of times.
References:
Sood , S . & Kapil , A . ( 2008 ) . An update on Trichomonas vaginalis . Indian J . Sex . Transm . Dis . , 29 : 7 – 14 .
Ryu ,J. & Min, Y. D.(2006). Trichomonas vaginalis and trichomoniasis in the Republic of Korea. Korean Journal of Parasitology .44:101-116.
3. López-Monteon, A. ; Gómez-Figueroa, F. S. ; Ramos-Poceros, G., Guzmán-Gómez, D., & Ramos-Ligonio, A. (2013). Codetection of Trichomonas vaginalis and Candida albicans by PCR in urine samples in a low-risk population attended in a clinic first level in central Veracruz, Mexico. Bio. Med. Research International.
4.Pondei, K.; Jeremiah, I. ; Lawani, E. & Nsikak, E. (2017). The Prevalence of symptomatic vulvo- vaginal candidiasis and Trichomonas vaginalis infection and associated risk factors among women in the Niger Delta region of Nigeria, International STD Research & Reviews. 5:1-10.
5.Sena, A. C.; Miller, W. C.; Hobbs, M. M.; Schwebke, J. R.; Leone, P. A.; Swygard, H. & Cohen, M. S. (2007). Trichomonas vaginalis infection in male sexual partners: implications for diagnosis, treatment, and prevention. Clinical infectious diseases, 13-22.
6.Malla,N.;Yadav,M. & Gupta, I. (2007). Kinetics of serum and local cytokine profile in experimental intravaginal trichomoniasis induced with Trichomonas vaginalis isolated from symptomatic and asymotomatic women . Parasit . Immunol . 29 : 101 – 105 .
7. Flores, N. & Rosa, J. (2015). Undoing appropriateness: Raciolinguistic ideologies and language diversity in education. Harvard Educational Review, 85: 149-171.
8. Miguel, M. G. (2010). Antioxidant and anti-inflammatory activities of essential oils: a short review. Molecules, 15: 9252-9287.
9. Hernández-González, J. C.; Martínez-Tapia, A.; Lazcano-Hernández, G.; García-Pérez, B. E. & Castrejón-Jiménez, N. S. (2021). Bacteriocins from lactic acid bacteria. A powerful71 alternative as antimicrobials, probiotics, and immunomodulators in veterinary medicine. Animals, 11(4), 979.
10. Viera, A. J. & Wouk, N. (2015). Potassium disorders: hypokalemia and hyperkalemia. American family physician, 92: 487-495.
11. Hirt, R.(2013). Trichomonas vaginalis virulence factors: an integrative overview. Sex Transm. Infect., 89:439–443.
12. Petrin, D.; Delgaty, K.; Bhatt, R. & Garber, G. (1998). Clinical and microbiological aspects of Trichomonas vaginalis. Clinical microbiology reviews, 11:300-317.
13. Al-Saeed, A. (2011). Gastrointestinal and cardiovascular risk of nonsteroidal anti-inflammatory drugs. Oman medical journal, 26: 385.
14. Garber, P. A. (1987). Foraging strategies among living primates. Annual review of Anthropology, 16: 339-364.
15. Saba, A.M. (2012) .The using of in- pouch TV system culture as method for Trichomonas vaginalis detection in Baghdad Al- karkh MSc. Thesis, College of Science, Baghdad University.
16. Mason, B. D.; Wycoff, G. L. ; Hartkopf, W. I.; Douglass, G. G. & Worley, C. E. (2001). The 2001 US naval observatory double star CD-ROM. I. The Washington double star catalog. The Astronomical Journal, 122:3466.
17. Fredricks, D. ; Fiedler, T. ; Thomas, K. ;Oakley, B. & Marrazzo, J. (2007) . Targeted PCR from detection of vaginal bacteria associated with bacterial vaginosis . J. Clin. Microbiol. 45 : 327- 3276
