Bats are the main cause of human rabies in the United States and have been for several years, responsible for infecting seven of every 10 people who develop the disease, the Centers for Disease Control and Prevention reported on Wednesday.

Even though the actual number of rabies cases is very small, the C.D.C. made its announcement to raise awareness that bats carry rabies, said Dr. Emily Pieracci, a veterinarian with the agency.

The United States has one to three reported human cases of rabies a year. There were two deaths in 2018, and none so far in 2019.

Worldwide, rabies kills about 59,000 people yearly, almost all of those from dog bites. Rabies is 100 percent preventable if a series of shots is received before symptoms start. The United States has been free of the canine rabies virus since 2004 because of extensive vaccination of dogs, but other variants are present in wildlife, particularly bats, foxes, skunks and raccoons.