II. Epidemiology

  1. Endemic Regions (tropical Americas)
    1. Mexico
    2. Central America
    3. South America
  2. Prevalence (estimated)
    1. Endemic regions: 8-11 Million infected
    2. United States: 300,000 infected
      1. Most cases are via immigration and travel
      2. However vector-borne transmission has occurred in Southern U.S.
      3. Bern (2011) Clin Microbiol Rev 24(4): 655-81 [PubMed]

III. Pathophysiology

  1. Organism
    1. Parasite: Trypanosoma cruzi
  2. Transmission: Vector borne (primary source)
    1. Triatomine bug (reduviid bug, assassin bug or kissing bug) is an Insect that feeds on blood
      1. Triatomine bugs nest in the crevices of mud and clay houses
      2. Triatomine bugs are nocturnal and feed on humans as they sleep
      3. Acquires T. cruzi via ingested blood containing the Parasite as trypomastigote
      4. Trypomastigotes differentiate inside the Insect midgut into epimastigotes which further multiply
      5. Epimastigotes differentiate into the infective form, metacyclic trypomastigotes
    2. Insect carrying the Parasite defecates into a human wound site or mucous membranes (e.g. Conjunctiva)
      1. Parasite is initially transmitted from Insect to human as metacyclic trypomastigote
      2. Metacyclic trypomastigotes differentiate into amastigotes on human cell penetration
      3. Amastigotes multiply via binary fission releasing trypomastigotes to infect other human cells
  3. Transmission: Other mechanisms
    1. Congenital (vertical transmission)
      1. U.S. congenital infections per year: 300
    2. Blood Transfusion
      1. U.S. Blood supply is screened for Trypanosoma cruzi since 2007
    3. Organ transplant
    4. Contaminated food
    5. Lab exposure

IV. Findings: Acute Phase

  1. Lasts for 4-8 weeks after infection
  2. Localized Edema at the bite site
  3. Often asymptomatic
  4. Rowana's Sign (20-50% of acute cases)
    1. Painless unilateral eye swelling
  5. Non-specific febrile illness (variably present)
    1. Malaise
    2. Headache
    3. Anorexia
    4. Non-pruritic rash
    5. Persistent Sinus Tachycardia

V. Findings: Chronic Phase

  1. Onset weeks to months after infection
  2. Life-long infection until treated
  3. Asymptomatic in 70-80% of cases
  4. Serious chronic manifestations occur in 20-30% of cases
    1. See Complications below

VI. Complications

  1. Cardiac
    1. Conduction abnormalities
    2. Apical aneurysm
    3. Dilated Cardiomyopathy
    4. Congestive Heart Failure
    5. Thromboembolism
    6. Peroicardial effusion
  2. Gastrointestinal
    1. Megaesophagus
    2. Toxic Megacolon
  3. Neurologic
    1. Cerebrovascular Accident risk
  4. Infants with congenital infection (vertical transmission from mother)
    1. Often asymptomatic
    2. IUGR with low birth weight in some cases
    3. Low APGAR Scores at birth
    4. Anemia
    5. Thrombocytopenia
    6. Hepatomegaly
    7. Splenomegaly
    8. Myocarditis (rare)
    9. Meningoencephalitis (rare)

VII. Labs

  1. Acute infection
    1. Peripheral Smear (Light Microscopy)
      1. Peripheral blood (or anticoagulated cord blood) for trypomastigotes
    2. Polymerase chain reaction (PCR)
      1. Highly specific and may be positive before Peripheral Smear demonstrates organisms
  2. Chronic infection
    1. Organism counts too low in chronic disease to be detectable by Peripheral Smear or PCR
    2. Serology tests for T. cruzi
      1. Positive on at least two different Serologic Tests (insufficient efficacy of any individual test)
      2. Enzyme-linked immunosorbent assay (ELISA)
      3. Immunofluorescent Antibody assay
    3. Adjunctive diagnostic modalities
      1. Echocardiogram (for Heart Failure)
      2. Electrocardiogram (for Arrhythmia)
      3. Upper endoscopy (for megaesophagus)

VIII. Diagnostics

  1. Electrocardiogram
    1. Obtain at time of diagnosis and as needed

IX. Management: Antiparasitic

  1. Protocol
    1. Treat immediately if not contraindicated
    2. Course of antiparasitic agent treatment is 60-90 days
    3. Perform physical exam to evaluate for end-organ involvement
    4. Electrocardiogram
  2. Contraindications to antiparasitic therapy
    1. Pregnancy
    2. Severe hepatic insufficiency
    3. Severe Renal Insufficiency
  3. Indications: Acute Chagas Disease
    1. Treat all acute Chagas Disease cases (if not contraindicated)
    2. Treat congenitally acquired Chagas Disease
    3. Treat Immunocompromised patients with reactivated Chagas Disease
  4. Indications: Chronic Chagas Disease
    1. All patients under age 18 years old with chronic Chagas Disease
    2. Patients under age 50 years old with chronic Chagas Disease and no advanced Cardiomyopathy
    3. Patients over age 50 years have had longterm infection that is unlikely to be cured with medication
    4. Consult CDC or infectious disease for management recommendations regarding specific case management
  5. Preparations (available in U.S. through CDC)
    1. Contraindications (see above)
      1. Pregnancy and Lactation
      2. Severe renal dysfunction
      3. Severe liver dysfunction
    2. Only two agents have proven efficacy
      1. Benznidazole
        1. FDA approved for ages 2-12 years old
      2. Nifurtimox (Lampit)
        1. FDA approved from birth to 18 years (weight >5 lb 8 oz or 2.5 kg)
  6. Adverse effects from treatment agents
    1. Weight loss
    2. Anorexia
    3. Polyneuropathy or Peripheral Neuropathy
    4. Rash
    5. Nausea

X. Management: Complications

  1. Congestive Heart Failure
    1. See Congestive Heart Failure Exacerbation Management
    2. Exercise caution with Beta Blockers (higher risk of Bradycardia)
  2. Atrial Arrythmias
    1. Cardiac Pacemaker (Heart Block, Sick Sinus Syndrome)
  3. Ventricular Arrhythmias
    1. Amiodarone
    2. Catheter ablation and placement of IACD
  4. Thromboembolism risk
    1. Consider antithrombotic therapy

XI. Screening

  1. U.S. Immigrants from Mexico, Central America or South America
  2. Children of mothers with Chagas Disease
  3. Blood donors in U.S.

XII. Prevention

  1. Blood donors in the United States are screened for T cruzi (since 2007)
    1. Not allowed to donate blood if positive
  2. Endemic area strategies
    1. Clean rooms
    2. Mosquito nets
    3. Insecticides

XIII. Resources

Images: Related links to external sites (from Bing)

Related Studies

Ontology: Chagas Disease (C0041234)

Definition (MSHCZE) Infekce parazitem TRYPANOSOMA CRUZI, forma trypanozomiázy vyskytující se ve střední a jižní Americe. Pojmenovaná po brazilském lékaři Carlosi Chagasovi, který tento druh objevil. Infekce je rozpoznatelná pouze z pozitivního sérologického výsledku, klinické příznaky se objeví až o několik let později – jsou to: destrukce parasympatických ganglií, kardiomyopatie, nefunkčnost jícnu nebo střev.
Definition (MEDLINEPLUS)

Chagas disease is caused by a parasite. It is common in Latin America but not in the United States. Infected blood-sucking bugs, sometimes called kissing bugs, spread it. When the bug bites you, usually on your face, it leaves behind infected waste. You can get the infection if you rub it in your eyes or nose, the bite wound or a cut. The disease can also spread through contaminated food, a blood transfusion, a donated organ or from mother to baby during pregnancy.

If you notice symptoms, they might include

  • Fever
  • Flu-like symptoms
  • A rash
  • A swollen eyelid

These early symptoms usually go away. However, if you don't treat the infection, it stays in your body. Later, it can cause serious intestinal and heart problems.

A physical exam and blood tests can diagnose it. You may also need tests to see whether the disease has affected your intestines and heart.

Medicines can kill the parasite, especially early on. You can also treat related problems. For example, a pacemaker helps with certain heart complications.

Centers for Disease Control and Prevention

Definition (NCI_CDISC) A parasitic infection caused by Trypanosoma cruzi and transmitted by the reduviid bug. It is characterized by an acute and chronic phase; in the acute phase patients may have fever, malaise, and swelling at the site of the insect bite. In the chronic phase patients develop hepatosplenomegaly, lymphadenopathy, cardiomyopathy and arrhythmias.
Definition (NCI) A parasitic infection caused by Trypanosoma cruzi. It is transmitted by insect bites. It is characterized by an acute and chronic phase; in the acute phase patients may have fever, malaise, and swelling at the site of the insect bite. In the chronic phase patients develop hepatosplenomegaly, lymphadenopathy, cardiomyopathy and arrhythmias.
Definition (MSH) Infection with the protozoan parasite TRYPANOSOMA CRUZI, a form of TRYPANOSOMIASIS endemic in Central and South America. It is named after the Brazilian physician Carlos Chagas, who discovered the parasite. Infection by the parasite (positive serologic result only) is distinguished from the clinical manifestations that develop years later, such as destruction of PARASYMPATHETIC GANGLIA; CHAGAS CARDIOMYOPATHY; and dysfunction of the ESOPHAGUS or COLON.
Concepts Disease or Syndrome (T047)
MSH D014355
ICD10 B57 , B57.2
SnomedCT 77506005
English Chagas' Disease, Disease, Chagas, Trypanosomiasis, South American, Disease, Chagas', Chagas Disease, CHAGAS DIS, Chagas disease, Chagas disease (diagnosis), Trypanosoma cruzi infection, T.cruzi, American trypanosomiasis NOS, Chagas Disease [Disease/Finding], chagas' disease, infection by trypanosoma cruzi, disease chagas, south American trypanosomiasis, chaga disease, t.cruzi, cruzi infection trypanosoma, t cruzi, chaga diseases, chagas disease, chagas diseases, South American Trypanosomiasis, Chagas' disease, American trypanosomiasis, Infection by Trypanosoma cruzi, South American trypanosomiasis, Chagas-Mazza disease, Infection by Trypanosoma cruzi (disorder), American; trypanosomiasis, Trypanosoma cruzi; infection, infection; Trypanosoma cruzi, Chagas, trypanosomiasis; American, trypanosomiasis; Trypanosoma cruzi, Trypanosomiasis, American, American Trypanosomiasis
Dutch ziekte van Chagas, T. cruzi, Trypanosoma cruzi-infectie, Amerikaans; trypanosomiasis, Trypanosoma cruzi; infectie, infectie; Trypanosoma cruzi, trypanosomiasis; Amerikaans, trypanosomiasis; Trypanosoma cruzi, Amerikaanse trypanosomiasis, Ziekte van Chagas, Chagasziekte, Trypanosomiasis, Zuid-Amerikaanse, Ziekte, Chagas-
French T.cruzi, Infection à Trypanosoma cruzi, Trypanosomose américaine, Fièvre barbeiro, Trypanosomose sud-américaine, Maladie de Chagas, Trypanosomiase sud-américaine, Thyroïdite parasitaire, Trypanosomiase américaine
German T. cruzi, Infektion mit Trypanosoma cruzi, amerikanische Trypanosomiasis, Chagas-Krankheit, Südamerikanische Trypanosomiasis, Trypanosomiasis, südamerikanische
Italian Trypanosoma cruzi, Infezione da tripanosoma cruzi, Tripanosomiasi americana, Tripanosomiasi del Sud America, Malattia di Chagas
Portuguese Infecção por Tripanosoma cruzi, T. cruzi, Mal de Chagas, Tripanossomíase americana, Doença de Chagas, Tripanossomose Sul-Americana
Spanish T. Cruzi, Infección por Trypanosoma cruzi, enfermedad de Chagas, infección por Trypanosoma cruzi (trastorno), infección por Trypanosoma cruzi, tripanosomiasis americana, tripanosomiasis sudamericana, Tripanosomiasis americana, Enfermedad de Chagas, Tripanosomiasis Sudamericana
Japanese クルーズ・トリパノソーマ感染, クルーズ・トリパノソーマ, アメリカ・トリパノソーマ症, シャーガスビョウ, クルーズトリパノソーマカンセン, クルーズトリパノソーマ, アメリカトリパノソーマショウ, Chagas病, ブラジル・トリパノソーマ症, シャーガス・クルーズ病, アメリカトリパノソーマ症, シャガス病, シャーガス病, ブラジルトリパノソーマ症, 南アメリカトリパノソーマ症, 南米トリパノソーマ症, トリパノソーマ症-南アメリカ, トリパノソーマ症-南米
Swedish Chagas sjukdom
Czech trypanozomiáza jihoamerická, Chagasova nemoc, Infekce způsobená Trypanosoma cruzi, Americká trypanosomóza, T. cruzi
Finnish Chagasin tauti
Korean 샤가스병
Polish Choroba Chagasa, Trypanosomatoza południowoamerykańska
Hungarian Trypanosoma cruzi fertőzés, Chagas-kór, T. cruzi, amerikai trypanosomiasis
Norwegian Not Translated[Chagas Disease]