Whooping Cough

Diagnosis based just on symptomatology is not particularly accurate, as the catarrhal stage may appear to be a heavy cold, a case of the flu, or bronchitis. Other viruses and tuberculosis infections cause symptoms similar to those found during the paroxysmal stage. The presence of a pertussis-like cough along with an increase of certain specific white blood cells (lymphocytes) is suggestive of B. pertussis infection, although it could occur with other pertussis-like viruses. The most accurate method of diagnosis is to culture (grow on a laboratory plate) the organisms obtained from swabbing mucus out of the nasopharynx (the breathing tube continuous with the nose). B. pertussis can then be identified during microscopic examination of the culture.