Communicable diseases: achievements and challenges for public health.

The past two centuries have seen enormous achievements in control of infectious diseases, previously the leading cause of death, in large measure due to sanitation and food safety, vaccines, antibiotics and improved nutrition. This has led people to put their faith in the notion that medical science would succeed in overcoming the remaining obstacles. Vaccination has eradicated smallpox, nearly eradicated poliomyelitis and greatly reduced many other highly dangerous infections such as diphtheria, tetanus and measles. New diseases such as HIV and new forms of influenza have taken both professional and popular opinion by surprise and have renewed the challenges before the world public health community. Emergence of antibiotic-resistant strains of common organisms due to overuse of antibiotics and lack of vaccines for many dangerous microorganisms poses problems to humanity. This stresses the need for new vaccines, effective antibiotics and strengthened environmental control measures. New knowledge of the microbiological origins of cancers such as that of the cervix, stomach and liver have strengthened primary prevention and brought hope that new cures will be found for other chronic diseases of infectious origin. Tragically long delays in adopting “new” and cost effective vaccines cause hundreds of thousands of preventable deaths each year in developing and mid-level developed countries. Gains are being made in control of many tropical diseases, but malaria, tuberculosis and other infectious diseases remain enormous global problems. Research and acquisition of new knowledge, risk communication, application of currently available means and fair distribution will be great challenges to public health in the coming decades.