Trends in leptospirosis epidemiology in France. Sixty-six years of passive serological surveillance from 1920 to 2003.
OBJECTIVE
The incidence of leptospirosis, a worldwide zoonosis, has significantly decreased in Western Europe during the last decades. Our aim was to analyse all reliable data collected at the Institut Pasteur from 1920 to 2003 to evaluate more precisely the evolution of the incidence of leptospirosis in France.


METHODS
The passive surveillance system used as early as 1920 allows the evaluation of leptospirosis incidence. Serological results inferred from the microagglutination procedure were used to evaluate variation in the incidence of the disease and the evolution of the Leptospira serogroups involved in the human disease.


RESULTS
No significant variation either in the number of leptospirosis cases or in the incidence of the disease was observed. However, the period of the 1970s was characterized by a rather low incidence. The weather plays a major role by modifying fresh water abundance, rodent populations and human behaviour. However the weather's influence is not the sole factor involved in the incidence rate. No cyclic variation was evident.


CONCLUSIONS
Although France has the highest incidence of leptospirosis in Europe, the analysis of serological data collected over 66 years has allowed us to conclude that in France, the incidence is slowly decreasing.
Baranton
Guy
G
Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France.
Postic
Danièle
D
D000372:Agglutination Tests; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D005602:France / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007919:Leptospira / Q000145:classification* / Q000276:immunology; D007922:Leptospirosis / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology; D011159:Population Surveillance; D012621:Seasons; D012703:Serotyping
D000907:Antibodies, Bacterial