Abstract
Background Listeriosis is a foodborne infection with a low incidence but a high case fatality rate. Unlike common foodborne diseases, the incubation period can be long. The first incubation periods were documented during a large listeriosis outbreak published in 1987 by Linnan and al. in the New England Journal of Medicine [range: 3 days to 70 days]. Data on the incubation period of listeriosis are scarce. Our study aim was to estimate precisely the incubation period of listeriosis using available data since 1987.
Methods We estimated the incubation period of listeriosis using available published data and data from outbreak investigations carried out by the French National Institute for Public Health Surveillance. We selected cases with an incubation period calculated when a patient had a single exposure to a confirmed food source contaminated by Listeria monocytogenes.
Results We identified 37 cases of invasive listeriosis [10 cases with central nervous system involvement [CNS cases], 15 bacteraemia cases and 12 pregnancy-associated cases] and 9 outbreaks with gastroenteritis. The overall median incubation period of invasive listeriosis was 8 days [range: 167 days] and differed significantly by clinical form of the disease [p