A highly contagious respiratory tract infection, also known as whooping cough, that is caused by germs called bacteria.

The germs that cause pertussis spread when an infected person coughs or sneezes. This sprays tiny germ-filled droplets into the air. The droplets are breathed into the lungs of anyone who happens to be nearby. A vaccine can help prevent serious illness. Often, the pertussis vaccine is given with vaccines for diseases called diphtheria and tetanus.

Pertussis symptoms often start about 7 to 10 days after infection. Early symptoms can include a runny or stuffy nose, fever, cough, and red, watery eyes. After a week or two, an ongoing cough may start. Serious coughing fits can cause vomiting, a change in face color and extreme tiredness. The cough may end with a high-pitched "whoop" sound.

Pertussis treatment often involves taking medicines called antibiotics that get rid of germs. Babies with pertussis usually need hospital care. Older children and adults often can be treated at home.