Hidden Dangers in the Great Outdoors

March 2021 by Dr. Dominique Sims

Let’s go on a journey through the forest, you’re on a hike with your dog and you stop to take a sip of water. Your hiking buddy needs a drink break too. But not from a water canister, from a small stream and you immediately begin to wonder…what’s in the water!? Giardia, the brain-eating amoeba (Naegleria fowleri), or perhaps a large, spirochete bacteria, Leptospira?

Leptospirosis is an infectious disease that causes serious illness in dogs, other animals, and people. Leptospires are long, thin, and flexible, spiralshaped bacteria that move by twisting and flexing. According to the Centers for Disease Control and Prevention (CDC) people and pets who enjoy outdoor activities where freshwater or wet soil are encountered may be at risk for leptospirosis.1 Outdoor activities can include swimming, kayaking, camping, and as mentioned hiking.1 If urine from an infected animal is deposited or drains into a body of freshwater or soil, the bacteria can survive there for quite some time.

The American College of Veterinary Internal Medicine (ACVIM) consensus statement on Leptospirosis reminds us that Leptospires may remain viable for weeks to months in urine contaminated soil and slow-moving or stagnant water.2 Leptospirosis is especially prevalent in areas with higher annual rainfall and warm climates.

Disease in dogs is caused primarily by Leptospira interrogans and Leptospira kirchneri and serovars are adapted to different wild or domestic animal reservoir hosts.2 Initial signs of leptospirosis include fever, lethargy, and lack of appetite. If left untreated, it can develop into a more severe, life-threatening illness that can affect the kidneys, liver, brain, lungs, and heart. Leptospirosis can be difficult to recognize initially, and diagnosing can be challenging.

Leptospirosis can certainly affect us in the great outdoors, but we also must remember that reservoirs can live closer to home. Small breed dogs and city and suburban dogs with minimal contact with water sources may be exposed after contact with urbanized wild animal populations.2 In addition, dogs that are exposed to urine from other infected animals such as in shelters or other pet care facilities, city parks, and even fenced yards are also at risk of developing leptospirosis. If you’re curious about our feline friends, the ACVIM consensus statement states that although serologic evidence of cats to leptospires indeed exists clinical disease in cats is rarely reported.2

So, if your dog takes a drink from a questionable water source, thankfully we can take precautionary measures to protect our canine companions. We can vaccinate dogs with vaccines containing the four most common serovars (Icterohaemorrhagiae, Canicola, Grippotyphosa, and Pomona.) The Nobivac® Lepto4 is the only 4-way leptospirosis vaccine proven to be effective against disease, mortality, and leptospiruria.3 Nobivac® Lepto4 is also available in 1 ml and 0.5 ml (Nobivac EDGE® Lepto4) formulations as well as in combination with the canine core antigens (Nobivac Canine 1-DAPPv+L4, Nobivac EDGE® DAPPv +L4).3

Enjoy the great outdoors and all it has to offer, except for Leptospirosis.


1 CDC: Leptospirosis Risk in Outdoor Activities (https://www.cdc.gov/leptospirosis/features/outdoor-activities.html), Accessed January 6, 2021

2 Sykes, et. al. 2010 ACVIM Small Animal Consensus Statement on Leptospirosis: Diagnosis, Epidemiology, Treatment, and Prevention J Vet Intern Med 2011;25:1–13

3 Nobivac: Stop Lepto (https://www.merck-animal-health-usa.com/nobivac/stop-lepto), Accessed January 6, 2021

About the author

Dominique Sims

Sr. Professional Services Veterinarian Pacific Northwest Region (AK, OR, WA)