Evidence of experimental biological interactions between different isolates of trypanosoma cruzi from the Chaco region

RAGONE PG; PEREZ BRANDAN C; TOMASINI N; MONJE RUMI MM; LAUTHIER JJ; CIMINO RO; BASOMBRIO MA; DIOSQUE P

Mar del Plata

Congreso; X Congreso de Protozoología y Enfermedades Parasitarias; 2014

Sociedad Argentina de Protozoología

Many infectious diseases arise from co-infections or re-infections with more than one genotype of the same pathogen. These mixed infections could alter host fitness, the severity of symptoms, success in the pathogen transmission and the epidemiology of the disease. Trypanosoma cruzi, the etiological agent of Chagas disease, exhibits a high biological variability often correlated with the genetic diversity. Here, we developed an experimental approach in order to evaluate biological interaction between three T. cruzi isolates belonging to different Discrete Typing Units (DTUs TcIII, TcV and TcVI). These isolates were obtained from a restricted geographical area in the Chaco Region; suggesting that they could be naturally co-infecting the same host. Different mixed infections involving combinations of two isolates (TcIII + TcV, TcIII + TcVI and TcV + TcVI) were evaluated in a mouse model. The parameters evaluated were number of parasites circulating in peripheral blood, histopathology and genetic characterization of each DTU in different tissues by DNA hybridization probes. The results suggest biological interactions between the analyzed isolates. We found a predominance of TcVI isolate in blood and tissues respect to TcIII and TcV; and a decrease of the inflammatory response in heart when the damage of mice infected with TcVI and TcIII + TcVI mixture were compared. In addition, simultaneous presence of two isolates in the same tissue was not detected, hence, that presence of one isolate could display a negative effect on isolates belonging to a different DTU. Overall, our results show that biological interactions between isolates with different biological behaviors lead to changes in their biological properties. The occurrence of interactions among different genotypes of T. cruzi observed in our mouse model suggests that these phenomena could also occur in the natural cycles in Chaco Region.