Abstract:Acute leptospirosis is an infrequent disease in sheep that can cause jaundice, haemolysis, haemoglobinuria, hepatitis and nephritis. In most reports the diagnoses have been made by clinical, pathological or serological evidence without isolation or direct identi?cation of the agent. Here, we report one con?rmed and one presumptive outbreak of acute leptospirosis in suckling lambs from two unrelated sheep farms in Uruguay with mortalities of 9/60 (15%) and 9/163 (5.5%) lambs. Both outbreaks occurred in Sep?Oct 2017 after heavy rainfall and ?ooding events. The main gross and histologic pathological ?ndings in two autopsied lambs, one from each farm, included severe di?use jaundice, haemoglobinuria, acute necrotizing hepatitis with cholestasis and interstitial nephritis. Leptospira interrogans serogroup Pomona serovar Kennewicki was isolated from sheep in both ?ocks and the same genotype was identi?ed directly in clinical samples from infected animals, including one of the deceased lambs subjected to autopsy, by ampli?cation and partial sequencing of rrs and secY genes. This serovar has recently been identi?ed in infected cattle and humans in Uruguay . The impact of Leptospira spp. infection in ovine health, and the epidemiologic role of sheep as reservoirs of leptospirosis for humans and animals need further investigation. © 2019 Blackwell Verlag GmbH