A sharp rise in parvovirus infections is putting pressure on animal hospitals as veterinarians report an unusual wave of cases hitting dogs and cats. The illness moves fast. It can be fatal without urgent care. And this season, clinics say they are seeing numbers that far exceed the norm.
At CareVet of Middletown in Ohio, Dr. Christopher Mapes described an escalation unlike anything in his recent memory. “It’s spreading so much more than we’ve ever seen it,” he told WHIO. His clinic typically handles only a handful of cases each year. As of fall 2025, they have treated nearly 20.
Parvovirus cases are rising at an unusually fast rate.
A Rapidly Moving Threat
Parvovirus attacks the gastrointestinal system, causing vomiting, bloody diarrhea and dangerous dehydration. Without treatment, the virus can overwhelm a young or unvaccinated animal in a matter of days.
The surge is not limited to dogs. Mapes said MedVet in Moraine is now “testing every animal that comes into the facility” because of a spike in feline cases as well, urging owners to limit contact with unfamiliar animals and wash hands frequently.
The rise comes as human parvovirus B19, a different virus that infects people only, is also experiencing an uptick. Health alerts from the CDC note rising activity across Europe and the United States, tracked through increased test positivity and antibody detection, Contagion reports.
But veterinary experts emphasize that B19 does **not** infect pets, a distinction the CDC makes clear in its public guidance.
Clinics that normally see a few cases a year are now seeing dozens.
Why the Spike Is Happening Now
Veterinarians say shifting social habits may play a role. During the height of the COVID-19 pandemic, people gathered less. Animals, like their owners, had fewer close contacts. As life returned to normal, pathogens found more hosts.
Human infectious-disease experts say a similar pattern is driving the rise in B19. Precautions reduced circulation, lowering immunity. “The recent surge… has been higher than in pre-COVID-19 years,” Dr. David Diemert told Contagion, after lowered exposure left more people susceptible.
Veterinarians suspect the same effect may apply in animal populations.
Both dogs and cats are being affected in this surge.
The Most Important Defense: Vaccination
Pet parvovirus spreads through contact with infected animals or contaminated surfaces. The virus survives in the environment for months, making vaccination essential.
Mapes stresses the importance of boosters. Pet owners should confirm past shots, then ensure vaccines are “up to date,” he told WHIO. Most parvo vaccines are given in a series, followed by a three-year booster schedule.
The CDC notes that while human B19 has no vaccine, prevention relies on good hygiene. For animals, similar precautions help: washing hands, sanitizing surfaces and avoiding high-risk exposure when outbreaks spike.
What Animal Rescuers Should Watch For
For shelters and rescue groups, vigilance matters. Sudden vomiting, lethargy or bloody stool should prompt immediate veterinary testing. Early fluids, antiviral support and isolation can save lives.
With cases climbing, every hour counts.