Just last month the Centers for Disease Control and Prevention declared victory over canine rabies in the United States -- a fatal virus that kills 55,000 people a year globally.
That declaration may have been premature.
A growing demand for overseas dogs -- many from countries where the disease is endemic and the animals are too young to be vaccinated -- has put rabies back on the government's radar and caused the CDC to go to work on stricter rules aimed at imported dogs.
As many as 300,000 puppies a year are being imported, based on early estimates, according to G. Gale Galland, veternarian in the CDC's Division of Global Migration and Quarentine.
Driving the import trend is the demand for puppies, rather than older dogs that have behavioral or health issues.
The Border Puppy Task Force in California estimates that 10,000 puppies entered San Diego County from Mexico in just one year. Some only a few weeks old are sold for $1,000 each in shopping center parking lots on the street.
"Most people don't think about this deadly disease," said Dr. Nina Marano, director of the regulatory unit at the CDC. "People take for granted that their dogs are not at risk."
Just this spring, a puppy from India got a clean bill of health from officials at Seattle Tacoma International Airport. Days later, at its destination in Alaska, the dog was diagnosed with rabies, according to Washington's Veterinary Board of Governors, which is investigating the case.
In 2004, Los Angeles saw its first case of rabies in 30 years with a puppy imported from Mexico. In Massachusetts, a dog imported from Puerto Rico -- a U.S. territory where stray dogs are rampant -- was diagnosed with the disease.
In response to this trend, the CDC has pledged to strengthen regulations that were written long before the burgeoning pet resale market.
So far, no humans have been infected from rabid dogs, but health authorities say that without preventive action, it's only a matter of time.
According to the World Health Organization, rabies is still common in much of Latin America, Eastern Europe, India and other parts of Asia -- regions where puppies are raised for commercial resale in the United States.
Under current regulations, puppies under 12 weeks of age are allowed to enter the country as long as they are kept in isolation for 30 days and later vaccinated.
Rabies is typically transmitted to humans through the bite of an infected animal. In the United States, rabies in domestic animals has declined dramatically since the 1950s, though it still exists among raccoons, foxes and bats.
Rabies is easily preventable by a vaccine, but the virus is virtually impossible to treat once symptoms begin.
The only known survivor of the disease was a Wisconsin girl who was bitten by a bat and was put into an induced coma in 2004. All other recent attempts to treat three other victims in the United States and one in Canada failed, and all four died.
Since the 1950s, travel rules have relied on the responsibility of individual dog owners, not international traders, said the CDC's Marano. Enforcement has been lax and inconsistent from state to state.
"We've been considering changing the regulations for quite some time when we realized there had been a change in the way people bring their animals into the U.S.," she said.