Trichomonas vaginalis and Trichomoniasis Overview

Study Notes

Classification

Kingdom: Animalia
Subkingdom: Protozoa
Phylum: Sarcomastigophora
Class: Flagellata
Genus: Trichomonas
Species: Trichomonas vaginalis

Name of Disease

Trichomonas vaginalis is commonly referred to as trichomoniasis or TV.
It is a prevalent sexually transmitted infection caused by a protozoan parasite.

Geographic Distribution

Trichomoniasis occurs worldwide with higher rates among individuals with multiple sexual partners.
Most common treatable STD in young, sexually active women.
Roughly 7.4 million new cases annually in women and men in the U.S.
World Health Organization estimates 170 to 190 million cases globally each year.
Estimates may be conservative due to sensitivity of wet mount microscopy (35%-60%).

Morphology

Exists exclusively in the trophozoite stage, which is oval or "pear"-shaped.
Slightly larger than a white blood cell, measuring 9 x 7 μm.
Has five flagella: four extend outside the cell, and one wraps along the organism's surface (function unknown).
A notable axostyle may aid in attachment and tissue damage.
Reproduces every 8-12 hours via binary fission.

Hosts

Humans are the only known host for Trichomonas vaginalis.
Primarily transmitted through sexual intercourse.

Life Cycle

Transmitted almost exclusively through sexual contact.
Infections can reside in the vagina and urethra in women, and the urethra in men.
Potential for pregnant women to transmit the infection to their baby during birth.

Clinical Symptoms

Symptom onset can occur 3 to 21 days post-exposure.
Many infected individuals remain asymptomatic; up to 50% of both men and women show no symptoms.
Women may experience:
- Unusual vaginal discharge (thin, greenish-yellow, frothy, musty smell)
- Vaginal soreness, inflammation, and itching
- Pain during urination and intercourse
- Lower abdominal tenderness
Men may notice:
- Thin, whitish penile discharge
- Pain or burning during urination
- Inflammation of the glands or foreskin (less common).

Diagnostic Stage

The trophozoite stage is the key for diagnosis.

Method of Diagnosis

Microscopic examination of wet mounts detects motile organisms, practical but less sensitive.
Sample collection from vagina, genital area, and urethra for testing.
Alternative methods include:
- Immunological techniques (Direct immunofluorescent antibody staining) - more sensitive but complex.
- Culturing the parasite - most sensitive, results take 3 to 7 days.

Control & Prevention

Using male condoms may reduce transmission risk.
Infection through water is unlikely; Trichomonas vaginalis dies in water after 45-60 minutes and in thermal water after 30 minutes to 3 hours.

Description

This quiz provides an in-depth overview of Trichomonas vaginalis, the protozoan responsible for the sexually transmitted infection, trichomoniasis. Explore its classification, geographic distribution, and morphological characteristics to understand this prevalent infection better.