The British Veterinary Association, which represents thousands of practitioners in the United Kingdom, felt compelled to hop onto Twitter last week to issue a notable statement: "There's currently no reliable scientific evidence to indicate autism in dogs (or its link to vaccines)."
The tweet came in response to a widely condemned call-out from the television show "Good Morning Britain" for pet owners who believe their dogs developed "canine autism" as a result of vaccines or who refuse routine shots over worries about side effects.
But the association also suggested its response had roots across the Atlantic: "We are aware of an increase in anti-vaccination pet owners in the U.S.," it said, "who have voiced concerns that vaccinations may lead to their dogs developing autism-like behavior."
So has the anti-vaxx movement, which has fueled measles outbreaks in recent years, spread to American pets?
Not exactly, say major U.S. veterinary groups.
The American Veterinary Medical Association firmly agrees with its British counterpart: There's no evidence for autism in dogs or any link to vaccines - a theory that has been thoroughly discredited in humans, says John de Jong, a Boston-area veterinarian and incoming president of the association. But he also said he never has been asked by a client about this notion, nor does he know of other veterinarians who have.
"I have never had a client voice that concern," echoed Heather Loenser, a senior veterinary officer with the American Animal Hospital Association, who said she's only "seen it pop up on social media from time to time."
No one tracks pet vaccination rates. That said, Loenser and de Jong said they've seen small increases in clients who question the shots' necessity or frequency De Jong said some are influenced by breeders who tell buyers to wait on shots until after a dog has produced litters, while others express a vaguer skepticism about possible side effects.
More generally, he said, the doubts reflect a pet "humanization" trend that has driven a surge in organic and grain-free pet food sales, expensive and invasive end-of-life care, and doggy fitness centers.
"It's fair to say that a lot of what we see in veterinary medicine seems to follow the curve of what's popular in human medicine," de Jong said. "The human-animal bond is at an all-time high, and people consider their pets as extended members of the family."
The rabies vaccine is required by law for dogs and cats in most states. Other "core" vaccines, including those for distemper and parvovirus in dogs, are strongly recommended. They have been highly effective, veterinarians note. Rabies has been eradicated in domestic canines, and distemper is extremely rare. De Jong said he treated dogs with parvovirus as a veterinary student in the early 1980s but now seldom sees it.
"If you take a look at the general health and longevity of both animals and people in society today, we have longer and healthier lives due to preventive medications, preventive health care, good diets and vaccines," he said.