Overview of the epidemiology of Chagas' disease in Chile]

Chile is a long and narrow country located in the south western coast of South America. Chagas' disease exists in the seven first (18 degrees 30'-34 degrees 36' South lat.) of the total of thirteen administrative regions of the country. In the 1982-1990 period a series of studies considering different epidemiological aspects of this parasitic zoonosis has been carried out with the following results: 5,601 rural of periurban dwellings were surveyed for the presence of Triatoma infestans (the most important and almost exclusive vector of Trypanosoma cruzi in Chile). 37.4% of the dwellings were infested according to the inhabitants and 29.4% were found infested according to the presence of tracks or insects captured. In 659 (17.2%) out of 3,822 T. infestans captured and examined T. cruzi was found in their abdominal contents. The most common sources of T. infestans feeding were mammals (89.0%), including man, and birds (9.5%). An indirect hemagglutination test (IHAT) for Chagas' disease, a very sensitive and specific reaction, was performed to 5,050 domestic mammals, resulting positive 7.9% of cats, 7.0% of dogs, 7.0% of goats, 4.9% of sheep and 4.1% of rabbits. 2,579 (16.9%) out of 15,418 persons were positive for the IAHT for Chagas' disease. The rates of infection were rather similar in males (17.5%) and females (16.2%) with an increase in infection rates in accordance with increase of age of individuals. The overall frequency of ECG abnormalities in positive IHAT persons was 18.7% against 8.8% in those with negative IHAT, whereas ECG abnormalities considered as suggestive of a chagasic etiology were 6.8% and 2.2% respectively. The esophageal motility in 311 persons with a positive IHAT and in 150 with a negative IHAT was found altered in 42.8% and 18.7% respectively. In the corresponding urban sectors of the 7 regions mentioned 2.7% of blood donors, 2.3% of delivering mothers, 2.6% of newborns and 0.6% of school children had positive IHAT. 646 chagasic women and 709 non-chagasic women in their reproductive span of life, and the products of the pregnancies that they had in a 6-year period were followed-up. No significant differences were found neither in the number nor in the evolution of pregnancies in both groups of mothers. Xenodiagnosis of children from chagasic mothers resulted positive in 6.3-8.9%, showing the transmission of T. cruzi by the placental route. Recently, 3 cases of congenital Chagas' disease of second generation have been demonstrated.(ABSTRACT TRUNCATED AT 400 WORDS)     

Maternal vitamin D intake and mineral metabolism in mothers and their newborn infants.

Pregnant women receiving daily supplements of 400 IU (10 microgram) of vitamin D2 from the 12th week of pregnancy had plasma calcium concentrations higher at 24 weeks but similar at delivery to those in control pregnant women who did not receive the supplements. Infants of the women receiving the supplements had higher calcium, lower phosphorus, and similar magnesium concentrations on the sixth day of life and a lower incidence of hypocalcaemia than infants of the control women. Plasma concentrations of 25-hydroxycholecalciferol, which showed a seasonal variation, were higher in mothers and infants in the treated group. Cord-blood calcium, magnesium, phosphorus, and 25-hydroxycholecalciferol concentrations correlated with maternal values at delivery. Breast-fed infants had higher calcium and magnesium and lower phosphorus and 25-hydroxycholecalciferol concentrations than artificially fed infants. A defect of dental enamel was found in a high proportion of infants (many of whom had suffered from hypocalcaemia) born to the control women. These results suggest that vitamin D supplementation during pregnancy would be beneficial for mothers, whose intake from diet and skin synthesis is appreciably less than 500 IU of vitamin D daily.     

Leptin concentrations in cord blood in normal newborn infants and offspring of diabetic mothers.

Leptin has been implicated in the regulation of body weight and energy balance; Leptin is produced by adipocytes and placental tissue. Chronic fetal hyperinsulinemia and accelerated fetal growth with increased amounts of body fat are frequent findings in the offspring of diabetic mothers. In this study, we examined whether leptin levels in cord blood of infants of type 1 diabetic mothers (n = 29), gestational diabetic mothers (n = 6 and controls (n = 96) correlated with level of maternal glucose control, maternal leptin level at delivery, gender, fetal and placental size, and C-peptide in cord blood at birth. Leptin was significantly elevated in infants of type 1 diabetic (24.7 ng/ml) and gestational diabetic mothers (29.3 ng/ml) as compared to controls (7.9 ng/ml). C-peptide was also significantly higher in infants of type 1 diabetic (0.91 nmol/l) and gestational diabetic mothers (0.99 nmol/l) vs controls (0.34 nmol/l). Infants of type 1 diabetic mothers with a leptin level in cord blood above the upper normal range, i.e. > 30 ng/ml (n = 13), had an average maternal HbA1c level of 5.4% (normal < 5.5%) that was not different from 5.2% in infants with a leptin level < 30 ng/ml (n = 15). In both neonatal groups of diabetic mothers, leptin in cord blood did not correlate with maternal leptin concentrations, placental weight, birthweight, gender and cord blood C-peptide. In controls, leptin in cord blood was higher in girls than in boys (p = 0.044) and correlated significantly with birthweight (p = 0.41, p < 0.001) and cord blood C-peptide (p = 0.44, p < 0.001) but not with maternal leptin level or placental weight. The 3-4 times higher leptin levels in the offspring of diabetic mothers than normal could reflect increased adipose tissue mass and/or increased contribution from other sources such as placental tissue.