Lepto is a serious bacterial disease of mammals including dogs and humans. While many organisms may be attacked by the leptospira bacteria, the liver and/or kidney are the most frequently affected. Symptoms of the disease may include fever, vomiting, lethargy, abdominal pain, coughing and increased urination. If left untreated, death may occur. Diagnosis of lepto can be difficult. Leptospira bacteria are harbored in the bodies of wildlife, rodents and livestock, and are expressed in the urine of infected animals. Any surface water contaminated by this urine represents a source of infection to your pet. Increased rainfall may elevate your pet’s risk of contracting leptospirosis.