[Health service organization during the age of pestilence. 2]. / Excursus sull'organizzazione dell'assistenza in tempi di pestilenza. Seconda parte.

The author presents the history of the places where patients with epidemic pathologies were isolated. Since the study of medicine began, such places have been known as asclepiei, xenodochi, hospices, lazarettos, sanitary cordons, and quarantine stations and they contributed to controlling epidemics in Europe. Important not only in the context in which they were created, these structures expressed the medical culture and point of view of that age. Although very far from discovering the cause of the pathology due to their lack of scientific knowledge, the medical class sometimes knew how to effectively organize the isolation of patients. The history of such structures interweaves with the long history of Christianity and with the emerging nations of Europe and the city-states of the Italian Renaissance. Previously, in classical Greece and Imperial Rome there had also been "homes for the sick" to isolate patients. Today the world is periodically hit by epidemics. In such moments the medical profession uses its research ability and organizational capabilities but also historical memory to reduce epidemic contagion.

[Ecological interactions among Yersinia in their common reservoir, the rodent]. / Interactions écologiques des Yersinia au sein de l'hôte réservoir commun, le rongeur.

Plague, due to Yersinia pestis, is still active in various foci in the Americas, in Africa and Asia, whereas it has been absent from Europe since the end of the 18th century, after having killed the two-thirds of the continent's inhabitants within four centuries. Various hypothesis have been proposed to attempt to explain the spontaneous "eradication" of plague from Europe, including the improvement of hygiene and habitat, changes in the rat population and cross-immunity induced by other infections, such as salmonellosis, leprosy and other yersiniosis. The only Yersinia currently isolated in Europe are the species genetically related to Y. pestis, Y. pseudotuberculosis and Y. enterocolitica, which are less virulent and mostly enteropathogenic. Y. pestis and Y. pseudotuberculosis have a DNA relatedness of 90%, whereas it is of only 60% with Y. enterocolitica. Y. pseudotuberculosis has been used as efficient vaccine against plague. Present world epidemiological data show that Y. enterocolitica is progressively replacing Y. pseudotuberculosis. Experimental infection by Y. enterocolitica, inducing a transitory and spontaneously cured infection in the immunocompetent host, only inducing opportunistic infections in the immunodeficient host, promotes efficient immunity against plague. Thus, it seems likely that the emergence of some variants of Yersinia, less virulent than Y. pestis, but able to induce a long-lasting protective immunity against plague, have contributed to its eradication by a silent enzootic infection among the wild reservoirs of rodents.