A public health investigation is underway in Pennsylvania, Illinois, Indiana, New Jersey, and New York after an imported rescue dog was found to have rabies.

At least 12 people were exposed to the dog, which was among 33 dogs and one cat that arrived from Azerbaijan at O'Hare International Airport in Chicago on June 10, the Associated Press reported. The animals were not in the main cabin of the plane or main terminal of the airport. Travelers who were at the airport are not considered to be at risk, but health officials are checking to see if other animals in the shipment are infected and are still tracking down the pets' new owners.

Rabies no longer regularly spreads among dogs in the United States, but imported animals are considered a risk for new outbreaks. The infected dog was taken home by a family in Chester County, Pennsylvania, but it was euthanized after it began acting strangely. It later tested positive for rabies.

This is the fourth incident of rabies in a dog imported into the United States since 2015, the APreported. Starting July 14, there will be a year-long ban on the importation of dogs from more than 100 countries where rabies is still a problem, the U.S. Centers for Disease Control and Prevention recently announced. The ban is being imposed because of a spike in the number of puppies denied entry because they were not old enough to be fully vaccinated, the AP said.