Courtesy of CDC/Getty Images

The Centers for Disease Control in Atlanta is monitoring more than 200 people in 27 states who may have been exposed to a man infected with monkeypox.

The CDC is working to evaluate individuals who came into contact with the man who returned to Atlanta from Lagos, Nigeria. The man then departed Atlanta on a flight to Dallas, Texas, where he tested positive for the monkeypox virus.

"While rare, this case is not a reason for alarm and we do not expect any threat to the general public," said Dallas County Judge Clay Jenkins in a press release.

Monkeypox was first discovered in 1958 at a research facility where monkeys were housed for research.

The CDC first detected cluster cases of monkeypox virus in the United States in 2003. Approximately 20 cases of monkeypox were reported in Wisconsin, Illinois, and Indiana in 2003.

The viral disease was thought to be spread to humans by domestic prairie dogs being kept as household pets.

Mike Roemer/Getty Images

Tammy Kauter, of Dorchester, Wisconsin, contracted the monkeypox virus from one of her 2 pet prairie dogs. She is pictured with her family and pet, Chuckles, on June 9, 2003.

The sick prairie dog died but Tammy kept Chuckles because it was thought she was immune after recovering from the virus and couldn't contract the disease again.