Congenital Chagas disease: detection and molecular typing of natural populations of T.cruzi involved in vertical transmission

BURGOS JM; BISIO M; SEIDENSTEIN ME; ALTCHEH J; TALARICO N; PONTORIERO R; MARCELLAC M; MATZKIN R; FREILIJ H; MACCHI L; LEVIN MJ; SCHIJMAN AG

Rosario - Santa Fe - Argentina

Congreso; Reunión de la Sociedad Argentina de Protozoología; 2004

Sociedad Argentina de Protozoología

We report a prospective study of 60 chagasic pregnant women and a retrospective study of 6 mothers of newborns with congenital Chagas disease. METHODS: We studied the evolution of the parasitemia in peripheral blood samples, collected in a trimestral basis from 17 women, by means of kDNA-targeted PCR. Seven of them have completed the follow-up (5 samples: 3 maternal blood specimens, placenta and newborn´s blood); other eight are currently under follow-up, while less than five specimens could be collected from the other patients. We characterized the parasite lineage directly from blood samples using miniexon-PCR and 24S rDNA-PCR. The parasite populations found in mothers and their newborns were also profiled by kDNA-PCR followed by double digestion with HinfIAfaI and by LSSP-PCR from the same amplicons. RESULTS: During pregnancy, the parasitemia was positive in 17.6%, 23.5% and 47% of the 17 women studied at the 1st, 2nd and 3rd trimestral periods, respectively. Five out of 32 (15.6%) collected placentas were PCR positive, only one of them belonged to a PCR positive blood sampled woman. Regarding transmission, 5 of 23 (21.7%) newborns were PCR positive; three of them born from PCR positive blood sampled mothers. These results show a higher parasitemia at the 3rd trimester of pregnancy but no relation in parasite detection between blood, placenta and newborns. Furthermore, we determined the lineage of parasite populations directly from 3 infected newborns and one mother. All of them were T. cruzi II. Moreover, in 6 retrospective cases (mother and newborn PCR positives) the kDNA profiles within each mother-newborn pair were almost identical, but different among the tested pairs. This study was supported by WHO ID 20285.