In September 2016, a cluster of seven kayakers with clinical symptoms of leptospirosis with onset since July 2016 was reported to French health authorities. Human and animal investigations were undertaken to describe the outbreak, identify the likely place and source of infection and implement necessary control measures. We identified 103 patients with clinical symptoms of leptospirosis between 1 June and 31 October 2016 who lived in the Ille-et-Vilaine district in Brittany. Of these, 14 (including the original seven) reported contacts with the river Vilaine during the incubation period and were defined as outbreak cases: eight were confirmed by serology tests or PCR and six were probable without a laboratory confirmation for leptospirosis. All 14 cases were kayakers. Three distinct contamination sites were identified on a 30 km stretch of the river Vilaine. Nine cases reported having skin wounds while kayaking. None were vaccinated against leptospirosis. The outbreak was attributed to Leptospira kirschneri serogroup Grippotyphosa. Animal investigations did not allow identifying the possible reservoir. Leptospirosis outbreaks associated with freshwater sports are rare in temperate climates. The prevention of such outbreaks requires control of potential animal reservoirs in zones such as the Vilaine valley and that kayakers adopt the recommended individual prevention measures.

Leptospirosis is an under-reported and emerging zoonotic disease which is potentially fatal in humans. Rodents are the main reservoirs for pathogenic Leptospira spp., but diagnosis in these animals is difficult, and their infection, which does not induce symptoms, usually goes unoticed. Although the exposures of most human cases of leptospirosis are poorly documented, we were able to identify six human cases of leptospirosis which were associated with direct contact with pet rodents (mice or rats) in Belgium and France between 2009 and 2016. All cases had severe disease and for all, the presence of Leptospira spp. DNA in the kidneys of their pet animals was confirmed, strongly suggesting that excretion of leptospires in urine was the way of transmission. Half of the cases shared the serogroup Icterohaemorrhagiae, which is usually associated with severe disease, with the pet rats which they were in contact with. With the popularity of rats and mice as pets, this study should contribute to raising awareness on asymptomatic pet rodents as a source of Leptospira infections.

Leptospirosis is a zoonotic disease that is caused by spirochete bacteria of the genus Leptospira. Around the world, one million people each year are infected, leading to 60,000 deaths. Infection occurs through contact with environmental pathogens excreted by mammals (notably rodents). Data on Leptospira and leptospirosis in Africa are rather scarce, especially in urban habitats though these appear to be favourable environments for the pathogen circulation and human contamination. Using qPCR, DNA sequencing as well as MST/VNTR approaches, we examined Leptospira occurrence and genetic diversity in 779 commensal small mammals that were sampled over 2 years in the city centre of Cotonou, Benin, from three neighbourhoods with contrasting socio‐environmental conditions. Overall prevalence reached 9.1%. However, very marked variations in both space and time were observed, with local peaks of high prevalence but no clear seasonal pattern. In most sites that could be regularly sampled, Leptospira‐positive rodents were found at least once, thus confirming the widespread circulation of the pathogen within small mammal communities of Cotonou. Interestingly, an unusual diversity of small mammal‐borne Leptospira species and genotypes was retrieved, with up to four species and three different genovars within the same neighbourhood, and even instances of two species and two genovars identified simultaneously within the same household. To our knowledge, such a high genetic diversity has never been described at such a fine scale, a fortiori in Africa and, more generally, within an urban environment. Altogether, our results underline that much remains unknown about leptospirosis as well as the associated infectious risk in African cities where the disease may be massively over‐looked.

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