Every summer, hundreds of thousands of Americans wade through floodwaters after heavy rains, swim in rivers and creeks, compete in adventure races through mud and streams, kayak through wilderness waterways, and allow their dogs to drink from puddles along hiking trails. Most do not know that any of these activities carry a risk for leptospirosis — a bacterial disease spread through the urine of infected animals that can cause kidney failure, liver failure, meningitis, and death.
Leptospirosis is caused by bacteria in the genus Leptospira, shed in the urine of infected animals — rats, mice, cows, pigs, dogs, horses, and many wildlife species. The bacteria can survive in contaminated soil and water for weeks to months, particularly in warm, humid conditions that peak in summer. Humans are infected when Leptospira enters the body through cuts, abrasions, or mucous membranes after contact with contaminated water or soil. Swimming in or wading through potentially contaminated water — particularly floodwater, which can concentrate animal waste from flooded fields and urban drainage systems — is one of the highest-risk activities.
