Comparison of Tropical and Temperate Zone Diarrheal Problems

Abstract

In the past. we thought there were differences hetween tropica! and temperate zones in the etiology of intestinal diseases. Recent observations indicate that such differences do not exist. Infectious agents are ubiquitous. In general. diarrhea shows a much greater prevalence in the tropics, due to environmental conditions. With the exception of species requiring special habitats for maturation or completion of life cycles. practically all parasitic. bacterial. and viral agents associated with diarrheal disease are found worldwide. The rates of ameba and Shigella infection may he high in the arctic. The main determinants of the exceedingly high incidence of intestinal infection in the tropics are poverty. deficient education. and poor environmental sanitation. These promote intestinal infection from [he moment of birth. North America and Europe had similar problems at the turn of the 20th century. Labor and delivery in [he Indian population living in the Central and South American highlands occur at home without special preparauon. Fecal conraminauon is a common occurence and is conducive to infection of the newborn with pathogenic agents harbored by the mother. I Perinatal infection with parasites. enterobacteriaceae , and enteroviruses may occur in as high as 10% of such deliveries." Women delivering in clinics harbor fewer pathogens than their village counterparts. 3 If the infant receives colostrum and is adequately breast-fed. intestinal infections are rare and often asymptomatic. Breast-fed neonates shed Shigella organisms for a few days without clinical manifestations. The change to a mixed diet or to cow's milk results in a typical bout of dysentery. Pediatricians in the National Children's Hospital in Costa Rica successfully treat bacterial diarrhea wi[h maternal milk. A similar phenomenon occurs with Giardia.