Koch phenomenon

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Koch phe·nom·e·non

1. infection immunity; living tubercle bacilli, Mycobacterium tuberculosis, do not cause reinfection when inoculated into tuberculous guinea pigs. The animals are immune to reinfection even though their original infection continues to develop and eventually cause their deaths.
2. rise of temperature and increase of the local lesion in a tuberculous subject following an injection of tuberculin.

Koch phe·nom·e·non

(kōk fĕ-nom'ĕ-non)
1. The phenomenon of infection immunity; living tubercle bacilli (Mycobacterium tuberculosis) do not cause reinfection when inoculated into tuberculous guinea pigs (i.e., the animals are "immune" to reinfection) even though the original infections continue to develop and eventually kill the animals.
2. Rise of temperature and increase of the local lesion, in a tuberculous subject, following an injection of tuberculin.


Robert, German bacteriologist and Nobel laureate, 1843-1910.
Koch bacillus - (1) a species that causes tuberculosis. Synonym(s): Mycobacterium tuberculosis; - (2) a species that causes cholera. Synonym(s): Vibrio cholerae
Koch blue bodies - schizonts of Theileria parva, the causative agent of East Coast fever.
Koch law - Synonym(s): Koch postulates
Koch old tuberculin
Koch original tuberculin
Koch phenomenon - infection immunity.
Koch postulates - to establish the specificity of a pathogenic microorganism, it must be present in all cases of the disease; inoculations of its pure cultures must produce disease in animals, and from these it must be again obtained and be propagated in pure cultures. Synonym(s): Koch law
Koch-Weeks bacillus - a species found in the respiratory tract; causes acute respiratory infections. Synonym(s): Haemophilus influenzae; Weeks bacillus


named after Robert Koch, a German bacteriologist.

Koch blue spot, Koch blue body
Koch OT
Koch's old tuberculin, used in the tuberculin test.
Koch phenomenon
the role of delayed type hypersensitivity in the pathogenesis of tuberculosis.
K's postulates
a statement of the kind of experimental evidence required to establish the causative relation of a given microorganism to a given disease. The conditions are: (1) the microorganism must be present in every case of the disease; (2) it must be isolated and cultivated in pure culture; (3) inoculation of such culture must produce the disease in susceptible animals; (4) it must be observed in, and recovered from, the experimentally diseased animal.