Selective primary health care: strategies for control of disease in the developing world. XXI. Acute respiratory infections.

Acute respiratory infections represent an important cause of mortality in developing countries, especially among malnourished infants. The microbial etiologies are numerous and complex. Since vaccines effective against the likely major pathogens in the youngest children are not available, the acute respiratory infection control programs designed by the World Health Organization are based on simple schemes to classify illness according to severity and to treat bacterial infections early, thus preventing severe complications. These programs require careful planning to anticipate and circumvent local problems, and their efficacy should be monitored with care. In addition, research is needed in many areas: definition of the spectrum of organisms involved and the pathogenesis of severe infection; delineation of markers that will accurately identify patients needing antibiotics or hospitalization; performance of controlled trials of intervention strategies that will unequivocally identify effective methods; design and production of new, simple, and inexpensive diagnostic tools; and development of vaccines that will be effective in the target populations.