Mucosal infection and malnutrition

The mucosal infections that result in acute diarrheal diseases (ADD) and acute respiratory infections (ARI) account for more than one half of all the morbidity of infants and young children throughout the less developed countries. The importance of ADD and ARI stems from their capacity to impair nutrition and growth and cause premature death. The ADD are considered the main determinants of malnutrition, the main factors precipitating its severe forms, and one of the leading causes of death among children throughout the tropics and subtropics.8 The ARI, although not as prominent in the genesis of malnutrition as ADD, are very prevalent in children in the tropics often resulting in death, especially in children with deteriorated nutritional states.° Man has traditionally foreseen the development of practical solutions against ADD that would eventually control them, but a similar hope has not been nurtured with regards to the ARI. This contrasting reaction L.... reflects a better known epidemiology of ADD than of ARI. Measures to combat diarrhea have, therefore, been more readily implemented than possible control measures against respiratory diseases. The emphasis given in many countries to health education, water supplies, environmental sanitation, and more recently, oral rehydration therapy (ORT) has resulted in a remarkable decline in the diarrhea morbidity and in diarrhea deaths.2° A drastic reduction in deaths due to diarrhea in several tropical countries appears to induce a sharp decline in infant mortality. Not much was expected from orthodox measures to control ARI, due -to theirpreilominantly complex viral etiology, their entrenchment in the gemnitinity, and their poorly known ways of transmission. A significant decline in mortality due to ARI has, nevertheless, also been noted, especially in transitional countries like Costa Rica." As diarrheal diseases undergo rapid control, more interest has been placed on the study and understanding of ARI. 19 An improved knowledge of the etiology, epidemiology, and management of ARI, especially in less developed countries, will likely result in• the development of control and preventive, measures, as was the case with the ADD.