Leptospirosis is a severe and often fatal disease which dogs can contract through ingestion of infected material or when their irritated skin comes in contact with contaminated water or urine. The organisms, shed by raccoons and other wild and domestic animals can survive in the earth for months and can infected bodies of water including puddles. Vaccinating your dog yearly against the disease may prevent the illness all together or significantly reduce the severity of symptoms. Humans are susceptible to contracting the disease from all infected animals.