Leptospirosis is a zoonotic disease of global occurrence and may result in life threatening illness in animals and humans. Leptospira may also reside in the kidney of many animal species including dogs without causing disease. Factors predisposing to clinical disease, carrier stage, or protection needs to be clarified. Dog are susceptible to fatal illness and at the same time may serve as asymptomatic reservoirs. Protection from vaccines is short-lived and suboptimal. Information available on immune response in naturally infected dogs is sparse. The investigators hope to unravel the host and pathogen factors in Leptospira infection that leads to fatal disease, chronic asymptomatic infection, or bacterial clearance. Innate immune cells are the first line of defense against Leptospira infection, initial experiments will determine the response of innate immune cells of dogs. The knowledge acquired from this study will be beneficial for the development of control and treatment strategies for this problematic and life-threatening disease. As leptospirosis is a zoonotic disease where animal, human and environmental interface is essential for transmission, the findings from this study will have a “One Health” impact.