Observations on Experimental Chagas' Disease in Dogs

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Abstract
Summary 1. Experimental Chagas' disease has been produced in adult dogs by inoculation with culture forms of “A” and “B” strains of Trypanosoma cruzi and with blood forms of “W” strain. 2. Occasional spontaneous recoveries occurred in adult dogs but untreated infections in puppies were uniformly fatal. 3. The prepatent periods for “W”, and “A”, and “B” strains were: 5 to 10 days, 9 to 13 days, and 10 to 42 days, respectively. 4. The prepatent period was a little shorter in animals infected subcutaneously than in those infected intraperitoneally. 5. The prepatent periods and the survival times did not differ between the sexes but the parasitemias in males were higher than in females. 6. In unmedicated puppies death from acute myocarditis ordinarily ensued between 8 and 39 days following the appearance of trypanosomes in the blood. 7. The median survival time in untreated infections in puppies was 34 days from the time of inoculation; the shortest was 27, the longest 49 days. 8. Paraplegia was occasionally observed in adult dogs infected with “B” and “W” and occurred once in a puppy which survived the acute myocarditic stage as a result of medication with Bayer 7602. 9. Agglutination tests, using live culture as antigen, did not give consistent results during any of the periods of the disease. 10. The intravenous administration of Bayer 7602 did not usually alter the course of Chagas' disease in puppies; isopentaquine was usually not curative in tolerated doses. 11. Pentaquine, given orally, produced cures in puppies as evidenced by suppression of symptoms, eradication of parasites from the blood, survival, and absence of leishmania forms in the tissues at autopsy. 12. Although isopentaquine is more toxic than pentaquine in animals, the opposite is apparently the case in man; either compound might prove to be useful in clinical Chagas' disease.