Maternal fetal transmission of Trypanosoma cruzi: a problem of public health little studied in Mexico.

The first case of neonatal Chagas was reported in Mexico in 1998, but there have been no studies since then. Therefore, we investigated the rates of congenital infection of Trypanosoma cruzi by examining the seroprevalence among 1448 pregnant women in Oaxaca, Jalisco and Mexico City. We performed ELISAs to screen for recombinant and total antigens in mothers, and examined the frequency of congenital T. cruzi transmission by PCR with cord blood and antibody testing in children when they reached two years old. Our results showed that the prevalence of infection in pregnant women was 7.32% (106/1448) overall, and 4.4% (35/794) in Oaxaca, 12.02% (67/557) in Jalisco and 4.12% (4/97) in the Mexico City. In Oaxaca, T. cruzi infection was detected by PCR in 20% (7/35) of infants born to seroreactive mothers and 11.9% (8/67) in Jalisco. No infections were identified in infants from the Mexico City. From these only eleven serological follow up their children are agree to take blood. Therefore, the maternal-fetal overall transmission rate was 4.08% (4/98) in Oaxaca and 9.1% (3/33) in Jalisco 1.5% (1/65) children with positive serology were given specific treatment Chagas. In conclusion, these are the first reports of the rates of congenital Chagas disease in Mexico. The seroprevalence was higher in mothers from Jalisco, and could be related to that there is not the periodic fumigation of the transmitting vector performed in that state. The high rates of maternal-fetal transmission found in Oaxaca could be related to the differences of pathogenicity of trypanosome. No association between both the rate of congenital transmission and the gynecologic anthropometric data was observed.

Distancia filogenética de aislados de Giardia intestinalis de niños sintomáticos y asintomáticos / Phylogenetic distance between Giardia intestinalis isolates from symptomatic and asymptomatic children

The purpose of the present investigation, was to analyze the sequences of 16S ribosomal genes partially amplified from 17 isolated Giardia intestinalis obtained from faces of 13 children with intestinal pathology and four symptoms-free children with intestinal pathology. Analysis was made also with Giardia Portland-I and four Giardias isolated from dogs. Children ages in both groups ranged from six to twelve years. Genomic DNA was isolated using the phenol-chloroform-isoamyl alcohol technique, and partial amplification of 16S rRNA ribosomal gene was carried out by the Polymerase Chain Reaction. Sequences of rDNA were compared with Portland-I by using CLUSTAL-W (1.81) and PHYLIP (3.6) software in order to determine phylogenic associations. Our results showed that only one isolate from symptoms-free children and three from the symptomatic children were associated with Portland I. The other isolated Giardias were associated between them and with two samples obtained from dogs that are phylogenetically distant from Portland-I. Two isolates from dog constituted a different group. These results suggest a zoonotic infection and presence of symptoms in children from the present investigation; probably it was associated with host or special characteristics of Giardia strains. The last two situations have a special epidemiological and public health interest.