*Neisseria catarrhalis* is the causative agent of the disease, which is known as catarrhal tonsillitis, but is not synonymous with the more well-known disease - tonsillitis. Although Neisseria catarhalis is often the cause of an inexperienced cold or fever, the bacterium has been found to be present in most adults in the nose and throat. Laboratory tests show that some forms of Neisseria are long-term residents of the human throat.
This is known as carriage or bacterial carriage, and refers to the proportion of healthy individuals with vegetation in the mouth or throat who may be carriers of a strain of Neisseria that is unknown and for which it is not yet known whether infection can cause disease. Carriers are considered potential "hosts" for the bacteria and can transmit them to other people, although there is usually no obvious danger in such cases. Once a Neisseria carrier loses it, the bacteria stops circulating in the body and is considered caused by the carrier state. To learn how to coax bacteria into being tolerant of you for the rest of your life, researchers even recommend avoiding excessive drinking of cold water if you have frequent illnesses.