Leptospirosis is a contagious bacterial infection of animals, including cattle, sheep, rats and dogs. Humans are also at risk and so control is important to prevent human infection. After infection, the bacteria localise in the reproductive tract and kidneys causing spread of the bacteria in urine, which in turn can enter water sources. Clinical signs are milk drop and infertility/abortions. Chronic carriers may show no clinical signs but will continue to shed bacteria.
Control of leptospirosis is primarily through good biosecurity. Herds can become accredited by blood testing and culling any positive animals. A vaccination is also available although this is not compatible with accreditation.