Spatio-temporal dynamics of bacillary dysentery epidemics in France

Between 1999 and 2013, surveillance of bacillary dysentery through bloody diarrhoea was marked by an average attack rate of 620 per 100,000 inhabitants. Biological confirmation concerned less than 1% of cases. A dozen outbreaks of bloody diarrhoea were confirmed as shigellosis. This work will make it possible to specifically improve surveillance of these outbreaks. The descriptive method of epidemiological and biological data was used in addition to a literature review. The reconstructed history dates back to the first epidemics of dysentery in the Mayombe region in the early 1920s. Spatial dynamics show that the east of the country has the highest attack rates. The time series of bloody diarrhoea in the country shows a decrease from 2005, with no seasonal pattern. Epidemics of shigellosis are becoming rare and of low amplitude. These results suggest that the causes and determinants of the high incidence of bloody diarrhoea should be investigated. The rarity of dysentery epidemics calls for a search for explanatory factors.