Newly Recognized Diseases

Still other diseases are newcomers, only recently identified. WHO stated recently: “During the past 20 years, at least 30 new diseases have emerged to threaten the health of hundreds of millions of people. For many of these diseases there is no treatment, cure or vaccine and the possibility of preventing or controlling them is limited.”

Consider, for example, HIV and AIDS. Unknown only 15 years or so ago, they now afflict people on every continent. Presently, about 20 million adults are infected with HIV, and more than 4.5 million have developed AIDS. According to the Human Development Report 1996, AIDS is now the leading cause of death for adults under 45 in Europe and North America. Worldwide, some 6,000 people are infected each day—one every 15 seconds. Projections suggest that the number of AIDS cases will continue to rise steeply. By the year 2010, life expectancy in African and Asian nations hit hardest by AIDS is expected to drop to 25 years, according to one U.S. agency.

Is AIDS a unique, one-of-a-kind, disease, or could epidemics of other diseases emerge to create similar or even worse havoc? WHO answers: “Without doubt, diseases as yet unknown but with the potential to be the AIDS of tomorrow lurk in the shadows.”

Some New Infectious Diseases Since 1976

Where Cases

Year First Appeared

Identified Name of Disease or Were Identified

1976 Legionnaires’ disease United States

1976 Cryptosporidiosis United States

1976 Ebola hemorrhagic fever Zaire

1977 Hantaan virus Korea

1980 Hepatitis D (Delta) Italy

1980 Human T-cell lymphotropic virus 1 Japan

1981 AIDS United States

1982 E. coli O157:H7 United States

1986 Bovine spongiform encephalopathy* United Kingdom

1988 Salmonella enteritidis PT4 United Kingdom

1989 Hepatitis C United States

1991 Venezuelan hemorrhagic fever Venezuela

1992 Vibrio cholerae O139 India

1994 Brazilian hemorrhagic fever Brazil

1994 Human and equine morbillivirus Australia

*Animal cases only