Congenital Chagas disease: estimating the potential risk in the United States.

1 Several factors such as parasitemia in the mother, parasite strain, techniques used for diagnosis (microhematocrit, polymerase chain reaction (PCR), histopathology, and/or serology) as well as methodologic aspects (target population (underweight newborns) or the time after delivery in which the sample for testing is obtained), may contribute to these variations on rates of congenital T. cruzi transmission. For instance in Paraguay, detection of parasites by microhematocrit concen- tration detected 2 (3%) newborns with congenital Chagas disease among 65 newborns delivered by T. cruzi -infected mothers, but another infected infant was detected by PCR in this group. In another location, only PCR detected 3 (10%) congenital cases at birth among 30 newborns from infected mothers. Overall, six babies from both locations were posi- tive by PCR, and two were also positive by direct micros- copy. None of the newborns were found to have IgM-specific antibodies against T. cruzi at birth. 19 Also in Paraguay, 20 (1.44%) of 1,381 babies were found to be infected by the microhematocrit technique, but this technique missed 77 cases that were later detected by other techniques. PCR were positive in 60 (7.4%) of 815 babies, and conventional serology by an EIA was positive in 89 (7%) of 1,248 babies 6 months after delivery. At the end, PCR and serology failed to diagnose seven and two cases, respectively, of the 104 infected babies. 20 Abstract. Economic hardship and/or political turmoil stimulated migration of Trypanosoma cruzi -infected popula- tion from Latin American countries to the United States and Europe; originating cases of Chagas disease were trans- mitted through blood, organ donation, and vertical transmission. Hispanic immigrant women of reproductive age in the United States coming from Chagas disease-endemic countries accounted for 2,384,644, and 5,841,538 in 1990 and 2000, respectively. Considering the prevalence rates for T. cruzi infection in their country of origin and the risk of newborns from infected mothers to acquire congenital infection as 1.33% and 5%, we estimated that the number of T. cruzi -infected newborns was 85-318 in 1990 and 166-638 in 2000. Diagnosis of infection in the mother and newborns at risk is needed. A high rate of cure is achieved, almost 100%, when the offspring is treated early. Health authorities, professional associa- tions, physicians, and Hispanic groups should pay more attention to the subject.