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)  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

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  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.

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 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….)