Chronic Disease: Several chronic diseases once attributed to lifestyle or environmental factors (such as some forms of cancer, diabetes, heart disease, and ulcers) are actually caused by or intensified by an infectious agent. For example, the majority of peptic ulcers - long thought to be due to stress and diet - are now known to be caused by the bacterium Helicobacter pylori. Recent data indicate that Chlamydia pneumoniae infection may contribute to coronary artery disease. Findings such as these raise the possibility that some chronic diseases may one day be treated with antimicrobial drugs or prevented by vaccines.

Vaccine Development and Use: Childhood diseases such as diptheria, tetanus, polio, measles, mumps, rubella, and Haemophilus influenzae type b mennigitis have been virtually eliminated in the United States through universal vaccination. Smallpox has been eradicated worldwide, and polio may be globally eradicated by 2000. Several new vaccines are undergoing clinical evaluation (against Lyme disease, rotavirus, and invasive pneumoccocal disease). No effective vaccine exists for many new or re-emerging diseases such as HIV/AIDS, dengue, hepatitis C, and malaria. Increasing vaccination rates for adults and children is a high priority in the US.

USDHHS (1998), Preventing Emerging Infectious Diseases: A Strategy for the 21st Century, Atlanta: Centers for Disease Control and Prevention.