Trypanosomes: American Trypanosomiasis - Chagas disease

Question 1

Explain the life cycle of American Trypanosomiasis - Chagas disease?

Answer 1

Vector: kissing bug - Reduviid bugs (lives in substandard housing) bite and defecate simultaneously, depositing parasite

• scratches and inoculates themselves
• bloodstream invasion
• spreads to tissue: heart, GI, muscle
• Has also been transmitted via blood transfusion, organ transplant

Question 2

What are the clinical manifestations of Chagas disease (American Trypanosomiasis)

Answer 2

Asymptomatic/resolution phase - nothing
Acute Phase:
- children: fever, local swelling, periorbital edema (Romana sign), myocarditis, adenopathy
Chronic Phase:
- months to years later and only in 10-30% develop symptomatic chronic problems:
- cardiomyopathy with CHF, irregular HR
- Megaesophagus/megacolon- flaccid, dilated, won’t contract normally

-Immunosuppression may reactivate

Question 3

How do you diagnose American Trypanosomiasis (Chagas disease)?

Answer 3

• Consider first history of exposure–screen from risk areas due to difficulty in treating once chronic
  Acute: - ID trypanozomes in blood
  Chronic: serologic tests for IgG Ab
  Xenodiagnosis - infect a bug

Question 4

How do you treat American Trypanosomiasis - Chagas disease?

Answer 4

Acute - consult

- heart transplant possible in chronic

Question 5

How do you prevent American Trypanosomiasis - Chagas disease?

Answer 5

• Vaccine being investigated
• Chemoprophylaxis not feasible
• Try to control vector/housing situation