EMBL/EMBO Joint Conference 2002
Michel Glauser, Faculty of Medicine, University of Lausanne, Switzerland
Michel P. Glauser studied medicine in Lausanne, Hamburg and Berlin. At the University Medical Center in Lausanne, he got his MD thesis in immunology, followed by an internship and residency in internal medicine. He then trained in infectious diseases both at Yale University School of Medicine, and the University of California San Diego Medical Center. In 1978, he was appointed chief of the Division of Infectious Diseases at the University Medical Center in Lausanne, and associate professor (1985) and full professor (1990). Since 2000 he has been Dean of the Faculty of Medicine. Dr M.P. Glauser is a fellow of the Royal College of Physicians (London), and of the American Academy of Microbiology. He has been president of the International Immunocompromised Host Society, of the European Society of Clinical Microbiology and Infectious Diseases, founder and president of the Swiss Society for Infectious Diseases. For 12 years (1989-2001) he has been a member of the Research Council of the Swiss National Foundation for Research, and president of its Division of Biology and Medicine for four years. He has been president since 1992 of the Swiss National Program for research on AIDS. His research interests include experimental infections (pyelonephritis, endocarditis, septic shock), the molecular basis of severe infections related to innate immunity, infections in immunocompromised hosts including neutropenic cancer patients, and AIDS.
Big killers: Past, present and future
Socio-economic events and epidemics
Humans have evolved only very recently in the history of life, and have been exposed to microbes during their entire evolution. Bacilli like tuberculosis, viruses like poliomyelitis, parasites like malaria, and even prions like scrapie have thus apparently not impacted significantly on their development.
Indeed, for an epidemic to develop and endanger survival of large populations, there are two basic prerequisites:
- A great enough number of individuals at risk: no doubt that when humanoids were a few thousands individuals living in small herds in savannas, large epidemics were unlikely. In contrast, with the prospect of 10 billion humans in a few decades, the danger has never been so great.
- Optimal conditions for transmission of microbes, and optimal susceptibility of recipients.
There is a delicate balance between population numbers and optimal conditions for transmission. There are several modes of transmission of microbes to humans, that include air, water and food, sex, parasites, not to mention blood (which appeared only very recently). All these modes are closely linked to socioeconomic and cultural changes.
Examples of such close association can be taken among the three "Big Killers" discussed during this Conference. One is tuberculosis. While tuberculosis hasbeen present in humans for very long (there are prehistoric skeletons presenting with healed tuberculous scars), the probably most dreadful epidemic of tuberculosis occurred during the XVIIIth and early XIXth centuries, at the time of the opening-up to trade and travel. This led to the development of large industrial metropolitan centers, where poverty, crowding, inhumane working conditions, and poor nutrition led to an epidemic of tuberculosis of such a magnitude that historians believe it might have endangered the western civilization. This epidemic abated spontaneously though, due to improving living conditions, long before the discovery of the Koch bacillus and of the antituberculous drugs. Today, the epidemic of HIV may engender renewed conditions for the spread of tuberculosis. Indeed, the extreme contagiousness of the tuberculosis patients presenting with depressed immunity, the poor living conditions in countries with the highest prevalence of HIV seropositivity, the exploding resistance of the tuberculous bacilli are all of major concern for the future.
HIV is another frightening example of socio-economic events paving the way to exploding epidemics. While it is unclear when the virus evolved from its original simian host to humans, little doubts exist that the profound socio-economic changes that occurred in Africa at the end of World War II and subsequently were instrumental for the spread of the epidemic. These changes included the migration of rural populations to large, overcrowded metropolitan agglomerations, poverty, undereducation, and sexual promiscuity. Worldwide, the "sexual liberation" of the 60's, that included homosexual liberation and the development of "sexual tourism", as well as the epidemic of parenteral drug abuse, were all social and behavioral changes that offered the virus unprecedented chances for spreading. Had none of these changes occurred, would have HIV found its way?
Example like these two are numerous. Most epidemics developed while favored by subtle modifications in the human to microbe relations. There are lessons to be learned from the past and from the present in order to elaborate global strategies for the future. Thus, economic prosperity, social wealth and education are among the best ways to combat infections and epidemics. Epidemics are a social, an economic, as well as a scientific challenge that needs to be addressed by all sections of our society.