Trichomonas — Notes OmpathStudy

Morphology, Life Cycle, Pathogenesis, and Clinical Features Introduction Trichomonas is a genus of protozoan parasites that differ from other flagellates because they exist only in the trophozoite stage —they do not form cysts. Species of Trichomonas in Humans There are three species of Trichomonas that infect humans: Trichomonas vaginalis – Causes urogenital infections . Trichomonas hominis – A commensal in the intestine . Trichomonas tenax – A commensal in the oral cavity . Among these, T. vaginalis is the only pathogenic species . --- Trichomonas vaginalis History and Distribution T. vaginalis was first identified by Donné in 1836 in vaginal secretions . Trichomoniasis is a sexually transmitted infection (STI) with a prevalence of 5%–75% , depending on the population: 5% in general hospital patients . 75% in sex workers . --- Morphology of T. vaginalis Shape : Pear-shaped or ovoid. Size : 10–30 µm in length and 5–10 µm in breadth. Flagella :Has four anterior flagella for movement. A fifth flagellum runs along the undulating membrane, supported by a flexible rod called the costa . Axostyle : A rigid, rod-like structure running along the body and projecting posteriorly . Cytoplasm : Contains siderophilic granules (most numerous alongside the axostyle and costa). Motility : Rapid, jerky, twitching movement under a microscope. --- Habitat of T. vaginalis Females : Found in the vagina and cervix , sometimes in the Bartholin’s glands, urethra, and urinary bladder. Males : Found in the anterior urethra , prostate, and preputial sac. --- Life Cycle of T. vaginalis The life cycle of T. vaginalis occurs entirely in a single host (either male or female). Mode of Transmission Sexual transmission is the primary mode of infection. Often coexists with other sexually transmitted infections (STIs) such as: Candidiasis Gonorrhea Syphilis HIV Non-sexual transmission :Babies can get infected during vaginal delivery. Contaminated towels, toilet seats, and bath water have been implicated in transmission, but this is rare. The infective form is the trophozoite since T. vaginalis does not form cysts. Incubation period : Approximately 10 days (range: 4 days to 4 weeks). --- Pathogenesis of Trichomoniasis T. vaginalis primarily infects squamous epithelium (not columnar epithelium). Produces cysteine proteases, adhesins, lactic acid, and acetic acid , which:Disrupt glycogen metabolism . Lower vaginal pH , making the environment more favorable for infection. Obligate parasite : Cannot survive outside the host for long. Causes inflammation and tissue damage , leading to: Petechial hemorrhages and capillary dilation (causing the "strawberry cervix" appearance). Metaplasia and desquamation of the vaginal epithelium. Intracellular edema , resulting in chicken-like epithelial cells (a hallmark of trichomoniasis). --- Clinical Features of Trichomoniasis In Males Usually asymptomatic . Some may develop: Urethritis (pain and burning during urination). Epididymitis (inflammation of the epididymis). Prostatitis (inflammation of the prostate). In Females Symptomatic cases present with : Pruritic vaginitis (intense itching). Yellowish-green, frothy vaginal discharge (with a foul smell). Dysuria (painful urination). Dyspareunia (pain during intercourse). Cervical erosion (due to inflammation). Complications : Endometritis and pyosalpingitis (rare). Neonatal pneumonia and conjunctivitis (in infants born to infected mothers). Incubation period : 4 days to 4 weeks . --- Trichomoniasis, caused by T. vaginalis , is a common sexually transmitted infection that primarily affects the urogenital tract . While males are often asymptomatic , females may experience itching, frothy vaginal discharge, and discomfort . The parasite does not form cysts , meaning transmission occurs directly via sexual contact or, in rare cases, through contaminated fomites. The disease can be associated with other STIs , highlighting the importance of early detection and treatment . Laboratory Diagnosis, Treatment, and Prevention of Trichomonas vaginalis Laboratory Diagnosis The diagnosis of T. vaginalis infection is based on microscopic examination, culture, antigen detection, and molecular methods . 1. Microscopic Examination Microscopy is the most commonly used method for detecting T. vaginalis in clinical samples. a) Wet Mount Preparation Sample : Vaginal or urethral discharge, urine, or prostatic secretions. Technique :A saline wet mount is prepared and examined under a light microscope . Characteristic findings : Jerky, twitching motility of the trophozoites. Pear-shaped morphology of T. vaginalis . Abundant leukocytes , indicating inflammation. Sensitivity : ~60% (low sensitivity, multiple samples may be needed). b) Permanent Staining Fixed smears can be stained using: Acridine orange stain (fluorescent microscopy). Papanicolaou stain (used in Pap smears). Giemsa stain (for better visualization of trophozoites). c) Direct Fluorescent Antibody (DFA) Test Uses fluorescent