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4 | 2008-2009
The Letter
Academic year 2008-2009
Selected papers
Inaugural lectures

Chair of Microbiology and Infectious Diseases

Philippe Sansonetti
p. 23
Cet article est une traduction de :
Chaire de microbiologie et maladies infectieuses

Notes de la rédaction

Philippe Sansonetti gave his inaugural lecture on 20 november 2008. His course entitled “From microbes and men: War and Peace at mucosal surfaces” began on 27 november 2008.

Texte intégral

Extracts from the inaugural lecture:

1“As soon as living organisms became multicellular, they were faced with the need to socialize with microbes, the first to occupy the planet, and to establish with them a symbiotic relationship. Model multicellular organisms such as the worm Caenorhabditis, the fly Drosophila do host a resident microbiota and are sensitive to selected pathogens. The systems that govern the gestion of this interface, inherited from some of the most basic mechanisms of development, have remarkably been conserved throuthout evolution, from insects to higher primates. (…) The co-evolution between man and microbes cannot be summarized to the recognition and eradication of pathogens, it has also led to the tolerance of the commensal microbiota (…). As a matter of fact, man is a primate-microbes hybrid. We host ten times more bacteria on our surfaces compared to the number of somatic and germinal cells that altogether constitute our body. The intestinal tract alone hosts most of this microbiota . In this microbial environment, pathogens represent a minority, although their impact is immense: each year, infectious and parasitic diseases kill about 15 million individuals, among which 12 million children, some of them also causing devastating sequellae to the survivors. A disaster with major social and economic consequences in the developing countries that bear most of the burden with about 90% of infections occurring in these areas (…).

2The conditions for future emergence of new infectious diseases persist primarily due to socio-economical, environmental and ecological factors. The most impoverished regions of the planet – 2 billion individual live nowadays with less than one dollar per day – will pay the highest toll to emerging infectious diseases in the future. Among the strongest risk factors is the steady growth of the world population (…), the increasing concentration of these populations at the periphery of expanding megapoles, in precarious conditions of hygiene and absence of education, the increasing invasion of forests in search of new resources that increases the chances of encounter of new vectors and wild animals that are reservoirs of innumerable new infectious agents. The steady increase of travels and international exchanges (2.1 billion passengers on airlines in 2006) has turned the planet into a global village where infectious agents travel as freely as individuals. It took little time for the SARS virus to disseminate from a remote region of China to Hong Kong, then Toronto.

3The control of infectious diseases is an achievable goal only if we succeed in creating, at the level of the planet, the conditions of a true “sanitary transition” that will need to fulfill requirements as diverse as: the discovery of new infectious agents, the development and use of vaccines against the major endemic and emerging infections, the improvement of sanitary conditions in suburban ghettos, the strengthening of surveillance networks and implementation of quick reaction strategies, particularly in the “South”. Internet likely saved us from SARS. The time ahs also come for a true anticipating surveillance, particularly in areas of the planet that are at high risk of transmission of infectious agents from wild animals. One should also consolidate a model of sustainable economy that takes the issue of infectious diseases into account. Private-public partnerships have been implemented over the last years with the aim to achieve very focused programs such as eradication of a disease in a country or zone. Some have met great success, however it is the role of the State leaders to take responsibility for disease eradication on the long term, particularly through major efforts in education and prevention. The necessary funds seem enormous, they are actually negligible with regards to the cost of a pandemics, once it has gone out of control. Research is the best investment that can be proposed (…).

4To conclude, I would like to cite Charles Nicolle to whom this lesson is modestly dedicated “la connaissance des maladies infectieuses enseigne aux hommes qu’ils sont frères et solidaires. Nous sommes frères parce que le même danger nous menace, solidaires parce que la contagion nous vient le plus souvent de nos semblables”. “Understanding infectious diseases teaches to man brotherhood and solidarity. We are brothers because the same danger threatens us, united because contagion often comes to us from our fellow men”. n

5The inaugural lecture is available from Editions Fayard. The video is available on the College de France website.

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Pour citer cet article

Référence papier

The Letter of the Collège de France, Collège de France, Paris, juin 2009, p. 23. ISSN 1958-1408

Référence électronique

Philippe Sansonetti, « Chair of Microbiology and Infectious Diseases », La lettre du Collège de France [En ligne], 4 | 2008-2009, mis en ligne le 15 novembre 2010, consulté le 25 mars 2017. URL :

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Philippe Sansonetti

Member of Académie des sciences. Director of the unité de Pathogénie microbienne moléculaire and unité INSERM 786, Institut Pasteur, since 2006.

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