Infectious disease transmitted by the urine of rodents that carry the germ leptospira. This infection is regularly characterized by an absence of clinical signs when the horses are HIV positive. However, in acute crisis, hyperthermia is observed, anorexia, coloring orange mucous membranes, gastrointestinal symptoms (diarrhea and constipation). In the chronic form, there repeated episodes of fever, weight loss, tired, oedema of the limbs and especially with eye signs of uveitis. Screening is done by blood tests with serology.