Infection with different Trypanosoma cruzi populations in rats: Myocarditis, cardiac sympathetic denervation, and involvement of digestive organs

We tested four isolates of Trypanosoma cruzi to assess parasite virulence a nd ability to cause myocarditis, cardiac sympathetic denervation, and histo pathologic alterations in organs of the digestive system. The susceptibilit y of rats depends on the population of T. cruzi, with the ABC strain and th e CL-Brener clone killing all animals, regardless of the parasitemic patter n. All tested T. cruzi populations caused acute myocarditis, but failed to induce histologic alterations in the intestine. The Cl-Brener and ABC isola tes caused esophageal myositis. The myocarditis caused by the ABC, CL-Brene r, and Y isolates was severe, but resolution started at the end of the acut e phase. In contrast, the Col 1.7G2 clone induced mild and sustained myocar ditis. Our results also showed that T. cruzi populations able to induce sev ere acute myocarditis caused marked sympathetic denervation, but recovery o f normal cardiac histology and innervation occurred. The sustained myocardi tis induced by Col 1.7 G2 clone failed to cause sustained denervation.