Curing by Infecting: Two strains competition during acute phase of Chagas ’ infection.

SHIRLENE VEGA; GUSTAVO J. SIBONA; C. A. CONDAT

La Falda, Córdoba

Simposio; IV Simposio Regional de Mecánica Estadística, Teoría de la Información y Biofísica; 2011

Metibi

We have extended the analysis of our model for the acute phase of Chagas ’disease studying the competition between two parasite strains and one antibody species. Simultaneous occurrence of infections with two different T. cruzi linages in the same individual has been reported in the literature. The main result obtained from the model is the nonexistence of equilibrium among the immune system and both strains at the same time, indicating an indirect competition between the parasite populations to survive the antibodies attack. The model yields six possible outcomes that can be grouped into three main cases: healing, chronic disease and host death. The second case is subdivided in two, considering which strain survives; and the third case is subdivided in four, considering the different ways for the populations to grow without control. Our results agree with the reported clinical observations: it has been not found in any hemocultural test the coexistence of two strains of the Trypanosoma Cruzi in infected organisms, even in those places were different strains circulates. The experimental data and our model show how a first infection can provide inmunity to sucessive infections. Moreover this indicates that a similar, but not so infective strain can be use for vaccination.