Trypanosoma cruzi - Chagas Disease

Chagas disease or American trypanosomiasis is caused by Trypanosoma cruzi, a protozoan transmitted by infected Triatominae insects.

  • Diagnosis
  • Background
  • Lab Tests
  • References
  • Related Topics

Indications for Testing

  • Residency in endemic area
  • Recent travel to endemic area
  • Cardiomyopathy or prototypical gastrointestinal disease without obvious etiology

Laboratory Testing

  • CDC trypanosomiasis diagnosis
  • Acute phase (first 60-90 days)
    • Direct detection of parasites on blood smear (Giemsa stain)
    • IgM may be useful in acute infection
    • Polymerase chain reaction (PCR) is very sensitive when available
  • Nonacute (chronic) phase (>90 days)
    • IgG confirms chronic disease – by IFA, ELISA, IHA
      • World Health Organization (WHO) recommends ≥2 tests to confirm disease
    • Cross-reactivity with Leishmania spp may occur
    • PCR requires further validation

Differential Diagnosis

Epidemiology

  • Prevalence
    • Almost exclusively in immigrants from Central and South America in the U.S.
    • 16-18 million individuals infected worldwide
  • Transmission
    • Triatominae vector species (kissing bug)
    • Maternal transplacental transfer (congenital)
    • Blood transfusion from infected donor
    • Organ transplantation
    • Ingestion of contaminated food/water (rare)

Organism

  • The genus Trypanosoma contains many species of protozoans
    • Only 3 cause human disease – T. cruzi, T. brucei gambiense, and T. brucei rhodesiense
    • Vector-borne from the reduviid Triatoma gerstaeckeri and others
      • Exposure to feces deposited on skin by infected bugs

Clinical Presentation

  • Acute phase
    • Mild symptoms occur for 2 weeks to 3 months
      • Romaña sign – unilateral painless edema of palpebral and periocular tissues
    • Initial signs include malaise, fever, anorexia, rash, and edema
    • Acute myocarditis in small percentage of cases
    • Indurated area of erythema and swelling (chagoma) may indicate parasite entry site
    • Frequently undetected at this stage
  • Chronic phase
    • May manifest decades later
    • Cardiomyopathy with arrhythmia
      • ~20-30% of patients (Bern, 2015)
      • Earliest sign is conduction defects – patient usually asymptomatic
      • Symptoms of biventricular failure – peripheral edema, hepatomegaly
      • ~60% experience sudden cardiac death
    • Digestive system complications
      • Megacolon
      • Ranges from mild achalasia to megaesophagus
  • Congenital disease
    • Highest risk for infection when maternal parasitemia is high during acute phase
    • Prematurity, hepatosplenomegaly, meningitis/encephalitis
  • Immunocompromised hosts
    • Organ transplant recipients – more severe clinical spectrum including acute myocarditis and congestive heart failure
    • Immunocompromised patient with reactivation – most common are meningoencephalitis, brain abscess, and acute myocarditis
Tests generally appear in the order most useful for common clinical situations. Click on number for test-specific information in the ARUP Laboratory Test Directory.

Parasites Smear (Giemsa Stain), Blood 0049025
Method: Stain

Recommended Use 

Screen for and detect spirochetes and blood parasites, including microfilaria, Babesia, Trypanosoma, and Plasmodium species

 Patient's travel history is necessary to aid in test interpretation

Trypanosoma cruzi Antibody, IgM 0051075
Method: Semi-Quantitative Indirect Fluorescent Antibody

Recommended Use 

Aid in the diagnosis of Chagas disease (T. cruzi); may be useful in acute phase of disease

Order in conjunction with blood parasite screen

Trypanosoma cruzi Antibody, IgG 0051076
Method: Semi-Quantitative Enzyme-Linked Immunosorbent Assay

Recommended Use 

Aid in the diagnosis of nonacute (chronic phase) Chagas disease (T. cruzi)

Follow-up 

If test results equivocal, repeat testing in 10-14 days

General References

Bern C, Montgomery SP, Herwaldt BL, Rassi A, Marin-Neto JA, Dantas RO, Maguire JH, Acquatella H, Morillo C, Kirchhoff LV, Gilman RH, Reyes PA, Salvatella R, Moore AC. Evaluation and treatment of chagas disease in the United States: a systematic review. JAMA. 2007; 298(18): 2171-81. PubMed

Bern C. Chagas' Disease. N Engl J Med. 2015; 373(5): 456-66. PubMed

Hemmige V, Tanowitz H, Sethi A. Trypanosoma cruzi infection: a review with emphasis on cutaneous manifestations. Int J Dermatol. 2012; 51(5): 501-8. PubMed

Lescure F, Le Loup G, Freilij H, Develoux M, Paris L, Brutus L, Pialoux G. Chagas disease: changes in knowledge and management. Lancet Infect Dis. 2010; 10(8): 556-70. PubMed

Rassi A, Rassi A, de Rezende JM. American trypanosomiasis (Chagas disease). Infect Dis Clin North Am. 2012; 26(2): 275-91. PubMed

Woodhall D, Jones JL, Cantey PT, Wilkins PP, Montgomery SP. Neglected parasitic infections: what every family physician needs to know. Am Fam Physician. 2014; 89(10): 803-11. PubMed

References from the ARUP Institute for Clinical and Experimental Pathology®

Malan AK, Avelar E, Litwin SE, Hill HR, Litwin CM. Serological diagnosis of Trypanosoma cruzi: evaluation of three enzyme immunoassays and an indirect immunofluorescent assay. J Med Microbiol. 2006; 55(Pt 2): 171-8. PubMed

Medical Reviewers

Couturier, Marc Roger, PhD, D(ABMM), Medical Director, Microbial Immunology, Parasitology and Fecal Testing, and Infectious Disease Rapid Testing at ARUP Laboratories; Assistant Professor of Clinical Pathology, University of Utah

Slev, Patricia R., PhD, Medical Director, Serological Hepatitis/Retrovirus, Immunology Core; Co-Medical Director, Microbial Immunology and Immunogenetics; Chief Medical Director, Immunology Division at ARUP Laboratories; Associate Professor of Clinical Pathology, University of Utah

Last Update: October 2017