For health professionals: Chagas disease (American trypanosomiasis)

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What health professionals need to know about American trypanosomiasis

Trypanosoma cruzi is a flagellated, protozoan parasite, which is endemic to regions of Latin America. It is the causative agent of American trypanosomiasis (also known as Chagas disease).

The infection can be:

  • chronic
  • asymptomatic
  • potentially fatal


Methods of transmission are:

  • via insect vector (reduviid bug or triatomine bug)
  • congenital
  • via organ transplant
  • via blood transfusion
  • consumption of food contaminated with Trypanosoma cruzi through contact with infected triatomine bug feces
  • laboratory accidents
    • for example, through accidental exposure via needle-stick or sharps injury to contaminated blood products

Clinical manifestations

Acute symptoms last for about 2 months after infection. Symptoms include:

  • skin lesions or a purplish swelling of a single eyelid
  • fever
  • headache
  • enlarged lymph glands
  • pallor
  • muscle pain
  • difficulty breathing
  • swelling and abdominal or chest pain

Chronic symptoms include:

  • gastrointestinal disorders (10%), typically esophageal or colon enlargement
  • cardiac disorders (30%)
  • heart failure (later complication)
  • neurological symptoms


During the acute phase:

  • parasites may be detectable in fresh preparations of buffy coat or stained peripheral blood specimens
  • polymerase chain reaction (PCR) testing may also help detect acute infection

After the acute phase, 2 or more serologic tests to detect Trypanosoma cruzi-specific antibodies can be done. These include:

  • enzyme-linked immunosorbent assay (ELISA)
  • immunoblot
  • immunofluorescent antibody test

Collect a blood sample and submit it to Canada's National Microbiology Laboratory.

Special testing devices

The Ortho Trypanosoma cruzi ELISA Test System is for the qualitative detection of antibodies to the parasite in human:

  • serum
  • plasma blood samples

This assay is designed for single donor testing.

This device:

  • has been approved by the U.S. Food and Drug Administration (FDA)
  • is CE-marked in the European Union, which stands for European conformity

Ortho-Clinical Diagnostics is conducting a post-market study to collect and report data on the clinical performance of the assay. There have been no incident reports or recalls reported against this device.


American trypanosomiasis can be treated with benznidazole and nifurtimox. Both medicines are almost 100% effective in curing the disease. But this is only if given soon after infection at the onset of the acute phase.

Treatment is also indicated for:

  • those in whom the infection has been reactivated (for example, due to immunosuppression)
  • infants with congenital infection
  • patients during the early chronic phase

Infected adults should be offered antiparasitic treatment to prevent, curb or halt disease progression. This is especially the case for those who show no symptoms.

The potential benefits of medication in preventing or delaying the development of American trypanosomiasis should be weighed against:

  • the long duration of treatment (up to 2 months)
  • possible adverse reactions (occurring in up to 40% of treated patients)

Benznidazole and nifurtimox should not be taken by pregnant women or by people with kidney or liver failure. Nifurtimox is also contraindicated for people with a background of neurological or psychiatric disorders.

Additionally, specific treatment for cardiac or digestive manifestations may be required.

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