ATLANTA (CBS Atlanta) – Researchers say the whooping cough is making its way around the country, and that it may be caused by a vaccine-resistant germ.

The illness, known also as pertussis, is both dangerous and potentially fatal – the Center for Disease Control and Prevention in Atlanta reported that there were almost 42,000 confirmed cases last year, which include 18 deaths.

“It’s quite intriguing. It’s the first time we’ve seen this here,” Dr. Tom Clark of the CDC told Counsel and Heal.

The whooping cough is a highly contagious bacterial disease caused by Bordetella pertussis. It can affect anyone, but is especially dangerous in infants and children.

“There are several theories as to why we’re seeing more pertussis,” Dr. Kenneth Bromberg, chairman of pediatrics and director of the Vaccine Research Center at the Brooklyn Hospital Center in New York City, told Counsel and Heal.

“The thought is that the bacteria have gotten smart and are eliminating the pertactin in themselves,” Broomberg added.

Broomberg was not directly involved in the study