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Tuberculosis (TB), also known colloquially as the "white death", or historically as consumption, [7] is a contagious disease usually caused by Mycobacterium tuberculosis (MTB) bacteria. [1] Tuberculosis generally affects the lungs , but it can also affect other parts of the body. [ 1 ]
Mycobacterium tuberculosis (M. tb), also known as Koch's bacillus, is a species of pathogenic bacteria in the family Mycobacteriaceae and the causative agent of tuberculosis. [ 1 ] [ 2 ] First discovered in 1882 by Robert Koch , M. tuberculosis has an unusual, waxy coating on its cell surface primarily due to the presence of mycolic acid .
Mycobacterium is a genus of over 190 species in the phylum Actinomycetota, assigned its own family, Mycobacteriaceae.This genus includes pathogens known to cause serious diseases in mammals, including tuberculosis (M. tuberculosis) and leprosy in humans.
Normally CD4+ helper T-cells secrete the cytokine IFN-γ which recruits macrophages and stimulates them to destroy tuberculosis bacteria and surround them, forming a granuloma to prevent spread of infection. [2] Granulomas wall off the TB bacteria and may arrest disease in a latent phase.
Even though it sounds bad, most people at this stage are actually asymptomatic or maybe have a mild flu-like illness. About 3 weeks after initial infection, cell-mediated immunity kicks in, and immune cells surround the site of TB infection, creating a granuloma, essentially an attempt to wall off the bacteria and prevent it from spreading.
For example, viruses are dependent on entering and hijacking host cells to use their resources for growth and reproduction, incapable of growing alone. [ 8 ] The third postulate specifies "should", rather than "must", because Koch's experiments with tuberculosis and cholera showed that not all organisms exposed to an infectious agent will ...
The Mycobacterium tuberculosis complex (MTC or MTBC) is a genetically related group of Mycobacterium species that can cause tuberculosis in humans or other animals. It includes: Mycobacterium tuberculosis; Mycobacterium africanum; Mycobacterium orygis [1] Mycobacterium bovis and the Bacillus Calmette–Guérin strain; Mycobacterium microti ...
Tissue tropism is the range of cells and tissues of a host that support growth of a particular pathogen, such as a virus, bacterium or parasite. [1] [2] Some bacteria and viruses have a broad tissue tropism and can infect many types of cells and tissues. [1] Other viruses may infect primarily a single tissue. [1]