noun, Psychology. 1. Also called operant conditioning, instrumental conditioning. a process of changing behavior by rewarding or punishing a subject each time an action is performed until the subject associates the action with pleasure or distress.
Pertussis is caused by the bacterium Bordetella pertussis. It is an airborne disease which spreads easily through the coughs and sneezes of an infected person. People are infectious to others from the start of symptoms until about three weeks into the coughing fits.
Pertussis is a very contagious disease only found in humans. It is spread from person to person. People with pertussis usually spread the disease to another person by coughing or sneezing or when spending a lot of time near one another where you share breathing space.