Bacteria from the Leptospira genus are the cause of the infectious disease called leptospirosis, which occurs almost everywhere in the world. It is often associated with jaundice and renal failure. The main source of infection are livestock and rodents. Bacteria enter the environment with milk, semen and urine. The infection occurs through damaged skin and mucous membranes. The incubation period is approximately 5-15 days. Symptoms of jaundice include: fever, lack of appetite, weakness, conjunctivitis, yellowing of the mucous membranes and then skin. Uricular manifestations include fever, increased thirst, pain in the lumbar region, mucositis on the mucous membranes, vomiting, diarrhea, polyuria turning later into the oliguria and progressing uremia.