Bordetella pertussis is a Gram-negative, aerobic coccobacillus of the genus Bordetella. It is the causative agent of pertussis or whooping cough and it is non-motile. There is no zoonotic reservoir thus humans are the only hosts.
Bacterium is spread by coughing and by nasal dripping after an incubation period of 7 to 14 days. Pertussis is an infection of the respiratory system and characterized by a “whooping” sound when the person breathes in. Before the vaccine was developed there were 5,000 to 10,000 people killed in the US every year by Pertussis.
It infects the host by colonizing lung epithelial cells. The surface protein of the bacterium, filamentous hemagglutinin, binds to sulfatides that are found on cilia of epithelial cells. Once attached it stops the cilia from beating thus preventing it from clearing debris from the lungs. This brings on coughing which expels some of the bacteria into the air where it can infect others. Along with coughing Bordetella pertussis can inhibit the function of the immune system.
Children under one are infected most often when they aren’t immunized. Symptoms are similar to a common cold, runny nose, sneezing, mild cough, and low-grade fever. Although it does cause coughing if a patient is currently not in a coughing fit there is no trouble breathing. This is due to the immune response being inhibited thus little mucus being produced.
It also produces a lymphocytosis-promoting factor that causes a decrease in the entry of lymphocytes into lymph nodes.