GENETIC VARABILITY OF A Tripanosoma cruzi POPULATION STRUCTURE FOUND IN SYLVAN CYCLES AT PARANÁ STATE, BRAZIL: EVIDENCE BY MULTILOCUS ENZYME ELECTROPHORESIS - SOCCOL, V. THOMAZ; BARNABE, C.; CASTRO, E.; MEMBRIVE, N.; LUZ, E.; TIBAYRENC, M. (Archives of Veterinary Science, 1999)