In 1997 and 2000, four clusters of salmonellosis cases involving different serotypes that occurred in Paris—and were linked to an unusually high number of Salmonella isolates at a single laboratory (Laboratory X) in Paris’s 15th arrondissement—were reported to the French Institute for Public Health Surveillance (InVS) by the National Reference Center for Salmonella and Shigella (CNRSS). In response to these outbreaks, the InVS initiated and conducted epidemiological investigations. (Excerpt)