Demand for pet dogs is far outstripping supply, and the imbalance is expected to worsen as young adults consider dog ownership a normal life stage (before kids), dog breeders face increasing regulation and the U.S. cracks down on illegal dog imports.

Why it matters: Rabies and other diseases that can jump from dogs to humans are cropping up in places where they were all but eradicated, a result of unscrupulous imports from countries with looser hygiene laws and health oversight.

Driving the news: On June 14, the CDC issued a temporary suspension of theimportation of dogs from more than 100 countries deemed at high risk for rabies, including Egypt, India, China, Russia and Ukraine.

• At the same time, the Healthy Dog Importation Act — a bipartisan bill recently introduced in the House and the Senate — would require that every dog coming to the U.S. have a health certificate with proof of vaccinations issued by a properly licensed veterinarian.

By the numbers: While the U.S. imports more than 1 million dogs a year, the annual demand for dogs — imported or not— is 8 million.

• The American Pet Products Association released its biennial pet owners' survey in June, showing that "pet ownership has increased from an estimated 67% of U.S. households that own a pet to an estimated 70%" over the prior survey.
• Millennials were the largest cohort of pet owners, at 32%, followed by Boomers at 27% and Gen X at 24%.

What they're saying: "People are shocked when they hear the number of dogs that have been imported to the U.S.," Sheila Goffe, vice president of government relations for the American Kennel Club, tells Axios.

• "Some are going to pet stores, some are going to shelters, a lot are being sold online."
• Goffe says the USDA and U.S. Border Patrol are ill-equipped to police batches of dogs that arrive in the U.S. in groups as big as 40 or 50, with fake health certificates that have been photocopied.

Context: The number of dogs going to shelters and being euthanized has plummeted over the last 50 years, thanks to the success of spay-and-neuter programs and the rise of "responsible dog ownership," in which people commit to keeping a dog for life.

• "There just are not enough dogs entering shelters" to meet demand, says Patti Strand, president and founder of the National Animal Interest Alliance, who has bred Dalmatians for 52 years.
• While shady "puppy mills" do exist, most domestic breeders are highly ethical but are being squeezed by state and local laws that limit conditions for breeding dogs, according to Goffe and Strand.
• The "canine freedom trail" is one of many programs through which people transport dogs from states where shelters are full or crowded (like Texas and Alabama) to states where there aren't enough adoptable dogs (like New Jersey and Minnesota).

Goffe and Strand say notions that shelters are overcrowded or that it's wrong to get a dog from a breeder are outdated.

• Today, it is primarily sick or dangerous dogs that are euthanized — and when you "rescue" a dog from a shelter, the animal may simply be a foreign import that was brought to the U.S. to slake demand.

What's next: The dearth of available dogs will worsen — as will shortages of veterinarians and veterinary technicians, predicts Mark Cushing, head of the consultancyAnimal Policy Group and author of the 2020 book "Pet Nation."

• Cushing says the mental health benefits of pet ownership are inestimable, as so many people have discovered during the pandemic. "Pets aren’t a fad, so we’re still in the beginning phase — and that will stun some people — of this surge of continuing demand for pets," he tells Axios.
• "People with one dog will get a second dog. People with one cat will get a second, or they’ll get a different species.”