Chagas Testing Icky things that can drop on you from your thatched roof! Abc 7-04 Chagas Disease

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Chagas Testing

  • Icky things that can drop on you from your thatched roof!
  • ABC 7-04

Chagas Disease

Chagas Symptoms

  • Acute: Uncommon- Chagoma(primary inflammatory skin swelling), lymphadenopathy, facial, eye swelling, encephalitis
  • Chronic- (often asymptomatic for >20 years)
    • Cardiac: Rhythm defects (RBBB), CHF
    • GI: Esophageal and Colonic dysmotility- megaesophagus and megacolon

Chagas Heart disease In US

  • Hager: NEJM (1991) 325:763
    • Prentation: Symptomatic AV block, CHF, anginal chest pain, sudden death, sustained ventricular tachycardia
    • EKG frequently suggested coronary artery disease. Majority had some EKG abnormality.
    • LV aneurysm 14/25, segmental akinesia 5/25 and diffuse hypkinesia 3/25.
    • Angiography required to rule out coronary disease

Chagas screening strategies

  • Limited geographic or ethnic origin screening proposed….but
    • 2/7 transfusion transmissions occurred in Western Canada..donors were Mennonite Missionaries who had spent time in S. America
    • Most recent transfusion transmission occurred in Rhode Island, following implementation of a diversity effort to increase donations among Hispanics.

Donor Demographics

  • Fastest growing minorities in Minnesota, US are Hispanics (Note: in much of Florida and California, they aren’t the minority!)
  • Many blood centers implementing collection programs targeting Hispanic donations (translating/preparing Spanish language materials & donor history)

Chagas Screening in Central and South America

Challenges to new testing

  • Sensitivity and specificity of new testing
    • Issues of cross-reactivity with Malaria and Leishmaniasis
    • Abbott test had 0.1% false positive repeat reactive tests.
    • No licensed confirmatory, hence no way to reinstate donors deferred due to false positive tests, either in clinical trials or if/when instituted

Chagas confirmatory testing

  • Various unlicensed assays available for confirmation including line immunoassay (LIA), Immunofluorescence, and radioactive immunoprecipitation assay (RIPA).
  • RIPA currently considered “gold standard” but only available @ ARC-Holland lab- D. Leiby and Dr. Kirchoff- University of Iowa

Chagas and the press

  • ARC very active in promoting need for Chagas testing.
  • Many recent lay press articles on potential for Chagas testing.
  • Several US Manufacturer’s currently working on EIA assay development and clinical trials planned. (Keep tuned….)

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