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Chagas Testing

Chagas Testing. Icky things that can drop on you from your thatched roof! ABC 7-04. Chagas Disease. Trypanosoma cruzi Endemic: Central & So. America (related to, but distinct from, sleeping sickness trypanosome in Africa)

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Chagas Testing

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  1. Chagas Testing Icky things that can drop on you from your thatched roof! ABC 7-04

  2. Chagas Disease • Trypanosoma cruzi Endemic: Central & So. America (related to, but distinct from, sleeping sickness trypanosome in Africa) • Infected reduviid (kissing) bug falls from thatched roof, defecates and inoculates skin • Clearly under-recognized cause of heart failure • Only 7 cases Tx transmission documented in US/Canada • Screened for in Brazil and other LA countries

  3. 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

  4. 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

  5. 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.

  6. 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)

  7. Chagas Screening in Central and South America • In many endemic areas dual EIA strategy used to screen for Chagas • Chagas is the leading cause of cardiac failure in many endemic areas • May be spread by direct innoculation, transfusion or even congenitally.

  8. 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

  9. 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

  10. 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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