Whooping cough is caused by Bordetella pertussis bacteria, which produce a toxin that paralyzes parts of the respiratory cells and leads to inflammation of the respiratory tract.

The incubation period for pertussis is anywhere from a week to a month. Once the disease takes hold, symptoms can last from a few weeks to a few months.

The initial symptoms of pertussis include cold symptoms such as runny nose and a mild fever and cough. Eventually, the other symptoms resolve and the patient is left with a persistent cough.

In children, the cough has a characteristic whooping sound — thus the name “whooping cough.”

In adults, the cough may not have that characteristic sound. In between fits of coughing, the patient usually feels normal.

In the early 1900s, pertussis infected approximately 200,000 Americans. That number declined to just a few thousand in the 1980s.

However, over the last five years pertussis has made a resurgence, with as many as 48,000 Americans affected.