NEGATIVE TISSUE PARASITISM IN MICE INJECTED WITH A NONINFECTIVE CLONEOF TRYPANOSOMA-CRUZI

Trypanosoma cruzi is a heterogeneous population of parasites as shown by differences between strains and cloned stock from the same strain. Herein we present evidence of the noninfectivity of CL-14, a clone der ived from the CL strain of T. cruzi. In a previous paper we reported t he absence of parasitemia and mortality in mice injected with metacycl ic trypomastigotes of this clone. To investigate further this lack of infectivity we did and extensive histopathological analysis in mice at different intervals after i.p. (5 and 15 days as well as 1, 4, and 12 months) or i.v. (5 and 30 days) injection of trypomastigotes. In spit e of a systematic search in all tissues and organs of the animals, no parasite or significant pathological change was detected in any of the tissue sections. These data suggest the inability of this clone to me diate infection and/or cause pathological alterations in vivo.