🐾 Leptospirosis in Dogs: What UK Pet Parents Need to Know

Leptospirosis in Dogs: What UK Pet Parents Need to Know

Let’s talk about a disease that might not be on every dog owner’s radar, but probably should be: Leptospirosis. While it’s not the most common illness we hear about in dogs, it’s one of the more serious—and it’s out there, especially in certain areas of the UK.

In this post, we’ll explore what leptospirosis is, how dogs catch it, signs to look out for, how to protect your pup, and yes—what it might mean for us humans, too.

What is Leptospirosis?

Leptospirosis is a bacterial infection caused by a group of bacteria called Leptospira. These bacteria are most commonly carried and shed in the urine of infected animals—especially rats, but also other wildlife, farm animals, and even dogs themselves.

The bacteria thrive in wet environments, so places like puddles, still water, ditches, and muddy fields are hotspots—especially after heavy rain or flooding. Dogs usually get infected by:

• Drinking or walking through contaminated water

• Licking contaminated surfaces

• Bacteria entering through cuts, eyes, nose, or mouth

How Infectious Is It?

Leptospirosis is considered highly infectious among animals and can survive in the environment for weeks. It can spread through direct contact with infected urine or through contaminated environments. Even dogs who don’t seem sick can shed the bacteria for weeks, putting other dogs—and people—at risk.

The disease isn’t incredibly common, but it’s far from rare either. Southern parts of England tend to see more cases, with some reports suggesting a rise in recent years linked to climate changes and urban rodent populations.

Symptoms to Watch For

Leptospirosis affects different dogs in different ways. Some dogs may show only mild signs, but others can become critically ill. Common symptoms include:

• Lethargy and weakness

• Vomiting and diarrhea

• Fever and shivering

• Increased thirst or urination

• Jaundice (yellowing of gums or skin)

• Bleeding or bruising

• Breathing difficulties

It primarily affects the kidneys and liver, and in serious cases, it can lead to organ failure or death. Early treatment with antibiotics can be life-saving, so if your dog shows unusual symptoms—especially after wet weather or being around water—call your vet right away.

The Vaccine: What You Need to Know

Vaccination is the best protection we have against leptospirosis. In the UK, the leptospirosis vaccine is considered a core vaccine, which means it’s recommended for all dogs due to the potential severity of the disease.

Vaccine Schedule:

• Puppies: Two initial injections (2–4 weeks apart), starting at 8 weeks old.

• Annual booster: Needed to maintain protection.

• Overdue? You may need to restart the primary course.

L2 vs. L4:

There are two main types of leptospirosis vaccine used in the UK:

• L2 (Bivalent): Protects against two serovars (strains) of the bacteria—suitable for dogs in lower-risk areas or those with sensitivities.

• L4 (Tetravalent): Covers four serovars, including those more commonly seen in UK outbreaks. This broader coverage makes L4 more commonly recommended, especially in urban or high-risk regions.

While both vaccines are generally safe, some dogs may have mild side effects like soreness at the injection site or slight lethargy for a day or two. Severe reactions are rare, and the benefits of protection far outweigh the risks.

Is It Dangerous to Humans?

Yes—leptospirosis is zoonotic, which means it can spread from animals to humans. People can become infected through direct contact with contaminated water, soil, or urine—especially if you have cuts or abrasions on your hands. Dogs can act as a source of infection for their owners, especially if they’re shedding the bacteria without obvious symptoms. In people, it can cause flu-like symptoms, and in more serious cases, lead to:

• Liver or kidney damage

• Meningitis

• Lung complications

While infections in humans in the UK are uncommon, they do happen—especially among vets, farmers, sewage workers, and people exposed to flood water or untreated environments. That’s why keeping your dog vaccinated is also a way of protecting yourself and your family.

Tips to Keep Your Dog (and Yourself) Safe

• Keep up with annual vaccinations—your vet can guide you on L2 vs. L4.

• Avoid letting your dog drink from puddles, ditches, or still water, especially in summer and autumn.

• Clean and disinfect areas where rodents may have urinated, especially in outbuildings or sheds.

• Wash your hands after handling your dog, especially if they’re muddy or wet after walks.

• If your dog becomes ill, let your vet know if they’ve been around standing water or rats.

Final Thoughts

Leptospirosis might not be the most well-known dog disease, but it's one that can sneak up quickly and hit hard. The good news? It's largely preventable. A simple vaccination schedule, a bit of awareness about the risks, and prompt action if your dog shows symptoms can make all the difference.

Whether your dog’s a puddle-jumper, a garden explorer, or just loves sniffing out adventure, staying informed is one of the best things you can do to protect them—and yourself.

Stay dry, stay safe, and give your four-legged friend an extra cuddle from us!