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, or whooping cough, is a highly contagious disease involving the respiratory tract. It is caused by a bacterium, Bordetella pertussis, which is found in the mouth, nose and throat of an infected person.ertussis starts as a mild, upper respiratory infection (a cold) - including sneezing, runny nose, fever and occasional cough. Within 10-14 days, the cough becomes more severe. Thick sputum may be present. These symptoms may persist for one to two months, occurring frequently at night.