Toxoplasma gondii

Toxoplasma gondii

 

Toxoplasmosis is caused by the parasite Toxoplasma gondii which infects both birds and mammals.

Epidemiology

  • Hot, arid climates have a low incidence of toxoplasmosis
  • Transmission
    • Usually oral (ingestion of raw or undercooked meat contaminated with infectious oocysts or tissue cysts)
    • May occur via blood transfusion, organ transplant and transplacentally from mother to infant

Organism

  • Obligate intracellular parasite

Risk Factors

  • Predisposition to severe toxoplasmosis infection is common in persons with acquired immunodeficiency syndrome (AIDS) or in persons who are otherwise immunocompromised

Clinical Presentation

  • Usually a mild or asymptomatic disease in adults
  • Constitutional signs and symptoms – prolonged fever, headache, lymph node enlargement, myalgias
  • Gastrointestinal signs and symptoms – hepatomegaly, hepatitis
  • Toxoplasmosis acquired in utero can result in blindness, encephalomyelitis, mental retardation, convulsions and death in infected neonates (TORCH syndrome)

Diagnosis

  • Laboratory testing
    • IgG, lgM antibodies in pregnant women
    • PCR in immunocompromised patients
    • As suggested by the CDC, any equivocal or positive result should be retested using a different assay (IgG Dye test, IgM ELISA, reflex to Avidity and/or other tests) from another reference laboratory specializing in toxoplasmosis testing
    • Recommend paired acute and convalescent antibody testing to confirm the presence of disease

Treatment

  • Toxoplasmosis can be treated
  • Early detection of the disease is crucial for effective therapy
  • Recommend treatment with antibiotics for patient with congenital infection or for a patient who is immunocompromised
  • Complete eradication of the parasite becomes difficult after long-term chronic infection

See Also