Direct molecular typing of T. cruzi lineages involved in congenital Chagas disease

BURGOS JM; BISIO M; DUFFY T; ALTCHEH J; FREILIJ H; FREILIJ H; LEVIN MJ; SCHIJMAN AG

Iguazú - Misiones - Argentina

Congreso; XL Reunión Anual de la Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular; 2004

Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular (SAIB)

Congenital Chagas disease (CgCD) affects 1 to 7% newborns of infected mothers. A factor in CgCD transmission may be the parasite strain. Trypanosoma cruzi has a multiclonal structure classifiedinto 6 major phylogenetic lineages: I and IIa-e, based on culture depending biochemical and DNA techniques. This study aimed to set up and apply PCR methods based on polymorphic sequences (mini-exon, 18S, 24S rDNA) to type T. cruzi lineages directly from peripheral blood of mothers and their newborns, as well as from CgCD suspected infants (n=33). Their parasite entities were also profiled by RFLP-PCR and LSSP-PCR from minicircle DNA amplicons (kDNA). RESULTS: T. cruzi IId was found in all mothers and their offspring. The kDNA profiles were almost identical within each mother-newborn pair, but different among the tested pairs. Eight of 10 CgCD suspected cases were infected by T. cruzi IId and two by T. cruzi I.The last ones were brother and sister of 2 T. cruzi IId infected children; they also depicted differential kDNA profiles associated to each lineage, suggesting a different source of transmission in this family. The RFLP-PCR patterns of the patients´parasite populations showed lower kDNA diversity than the observed in culture stocks of the same lineages. A higher degree of genetic diversity was also detected in bloodstream parasites of immunosupressed chagasic patients, suggesting that the immunological system of the host somehow regulates the diversity of T. cruzi populations.