What are signs of parvo in dogs?

Parvo hits fast, often catching owners off guard even with careful care. A puppy that was playful at breakfast might refuse kibble by lunch, and that loss of appetite is one of the first red flags. You might also notice lethargy—your usually energetic pup just lies on the floor, not reacting to their favorite toy or walk offer. These early signs can be easy to mix up with a mild stomach bug, but parvo progresses much quicker.

As the virus takes hold, severe gastrointestinal symptoms kick in. Vomiting becomes frequent, often bringing up yellow or clear fluid that may turn frothy. Diarrhea follows, typically watery and dark red or black—vets call this "hemorrhagic diarrhea" because it contains blood. This stage is dangerous because it leads to rapid dehydration; you might see your dog’s eyes sink slightly or their gums feel dry when you press them gently.

Fever is another key sign, though it can be tricky to spot without a thermometer. A dog’s normal temperature ranges from 100.5 to 102.5°F, so anything above that could signal trouble. Some dogs also show signs of abdominal pain—they might hunch their back, whimper when you touch their belly, or avoid moving around. Young puppies under six months are most at risk, but unvaccinated adult dogs can get parvo too.

If you notice these signs, acting fast is critical—and not just for your dog’s health. In many places, local animal welfare laws require reporting contagious diseases like parvo to prevent outbreaks. Skipping this step could lead to fines, and more importantly, put other dogs in your neighborhood at risk. Even a quick call to your vet or local animal control helps stop the virus from spreading further.

Preventing parvo starts with following vaccination schedules, which are often tied to local pet regulations. Most areas mandate core vaccines for puppies, including parvo, and booster shots for adults. Keeping unvaccinated puppies away from high-risk areas—like dog parks, pet stores, or sidewalks where other dogs frequent—also cuts down on exposure. Remember, parvo can live in soil or on surfaces for months, so even a quick sniff of contaminated grass could be dangerous.

Catching parvo early gives your dog the best chance of recovery, but prevention is always better than treatment. Stay alert to the signs, stick to vaccination rules, and don’t hesitate to reach out to your vet if something feels off. Your pup can’t tell you when they’re sick, so it’s up to you to spot the warning signs and keep them safe—while staying on the right side of local pet laws, too.