Which bacterium causes whooping cough?

The bacterium that causes whooping cough is Bordetella pertussis. It is a small, aerobic, Gram-negative coccobacillus that attaches to the ciliated cells lining the respiratory tract. Its toxins and other virulence factors interfere with the normal clearance of mucus, producing the characteristic severe coughing fits.

Whooping cough, also called pertussis, often begins like an ordinary cold with a runny nose and mild cough. After roughly one to two weeks, repeated coughing attacks may develop, sometimes followed by a high-pitched intake of breath called a “whoop.” Infants may not whoop at all and can instead develop pauses in breathing, making the disease particularly dangerous for them.

Bordetella pertussis is not the same organism as Bordetella parapertussis, which can cause a similar but often milder illness. The best prevention is vaccination, usually with a pertussis-containing combination vaccine such as DTaP or Tdap. Immunity can fade, so booster doses are important.