References:

  1. Global Infectious Diseases and Epidemiology Online Network: Infectious Diseases of the Philippines, 2013 eBook Edition, ISBN 978-1-61755-582-4, by Stephen Berger. Accessed here.

AgentPARASITE - Protozoa. Archezoa, Parabasala, Trichomonadea. Flagellate: Trichomonas vaginalis
ReservoirHuman
VectorNone
VehicleSexual contact
Incubation Period4 to 28 days
Diagnostic TestsMicroscopy of vaginal discharge
ELISA, culture, antigen detection tests available
Nucleic acid amplification
Typical Adult TherapyMetronidazole or Tinidazole 2g PO as single dose to both sexual partners
Typical Pediatric TherapyMetronidazole 5 mg/kg PO TID X 7d. OR Tinidazole 50 mg/kg PO X 1 (maximum 2 grams)
Clinical HintsVaginal pruritus, erythema and thin or frothy discharge; mild urethritis may be present in male or female
SynonymsPentatrichomonas, Tetratrichomonas, Trichomonaden, Trichomonas, Trichomonas vaginalis, Tricomoniasis, Tritrichomonas

10% to 50% of infections are asymptomatic.

  • Symptoms often begin or worsen during the menstrual period.
  • Infection is usually characterized by vaginal discharge and vulvovaginal irritation.
  • Dysuria may be present, and dyspareunia is common.
  • As many as two thirds of infected women complain of a disagreeable odor.
  • Abdominal discomfort is present in 5% to 12%.

Examination reveals a copious loose discharge that pools in the posterior vaginal fornix.

  • The discharge is yellow or green in 5% to 40%, and bubbles are observed in the discharge in 10% to 33%.
  • The material has a pH above 4.5 in 66% to 91% of cases.
  • Endocervical disease is not caused by T. vaginalis.
  • Punctate hemorrhages (colpitis macularis or “strawberry cervix”) are seen on colposcopically in 45% of infected women, but in only 2% by visual inspection alone.
  • Parasites can be recovered from the urethra and paraurethral glands in more than 95% of the women, and may explain the association of the infection with urinary frequency and dysuria.

Reported complications of trichomonal vaginitis include vulvar ulceration, and vaginitis emphysematosa—the presence of gas-filled blebs in the vaginal wall.

  • Gestational trichomoniasis may be associated with premature labor and low birth weight, postabortal infection or premature rupture of the membranes.
  • Spread of trichomonads beyond the lower urogenital tract is extremely rare.
  • Sporadic cases of neonatal pneumonia due to Trichomonas vaginalis are reported.

Trichomoniasis has been associated with endometritis, adnexitis, pyosalpinx, infertility, preterm birth, low birth weight, bacterial vaginosis, and increased risk of cervical cancer, HPV, and HIV infection.

  • In men, its complications include urethritis, prostatitis, epididymitis, and infertility through interference with sperm function.

Most men carrying trichomonads are asymptomatic; however, the organism is implicated in 5% to 15% of patients with nongonococcal urethritis.

  • The discharge from trichomonal urethritis is usually milder than that seen with other infections.
  • Epididymitis, superficial penile ulcerations (often beneath the prepuce) and prostatitis are also described.