What are the symptoms of canine distemper in puppies?

Puppies under six months old are most vulnerable to canine distemper, a viral disease that attacks multiple systems. Early signs often start with a mild fever, around 103-105°F, which might be mistaken for a common cold. You might notice your puppy eating less or turning away from their favorite treats, a subtle clue that something’s wrong.

As the virus progresses, respiratory symptoms become more obvious. Puppies may develop a runny nose, with discharge that starts clear and turns thick or yellowish. A dry, hacking cough is common too—you might hear it when they’re resting or after playtime. Some also get watery eyes, which can crust over and lead to squinting if left unchecked.

Gastrointestinal issues often follow or overlap with respiratory signs. Vomiting, sometimes with bile, and diarrhea (which may be watery or contain mucus) can quickly lead to dehydration. Watch for signs like sunken eyes or lethargy—puppies that usually bounce around but now lie still for hours need immediate attention. These symptoms can worsen fast, especially in unvaccinated pups.

Neurological symptoms are the most serious and may appear later, even if other signs seem to improve. You might see tremors in the legs, head tilting, or seizures—small convulsions that make the puppy’s body twitch. Some puppies walk in circles or have trouble standing, showing a loss of coordination. These signs mean the virus has attacked the brain, and treatment becomes much more challenging.

It’s critical to act fast because canine distemper is highly contagious and often fatal in puppies. In many places, local laws require core vaccinations, including for distemper, to protect public health and other pets. Skipping vaccines not only puts your puppy at risk but could also lead to legal consequences if they spread the virus. Always follow your vet’s vaccination schedule—most start at 6-8 weeks old, with boosters to build full immunity.

If you spot any of these symptoms, contact your vet right away. Early diagnosis with blood tests or physical exams can improve survival chances. Remember, prevention is key: keeping up with vaccinations and avoiding contact with unvaccinated dogs (like at public parks before your puppy’s fully vaccinated) follows both health best practices and local pet ownership laws. Protecting your puppy from distemper isn’t just about their health—it’s part of being a responsible pet owner.