<s>[INST] What is tuberculosis (TB)? [/INST] Tuberculosis is a bacterial disease caused by Mycobacterium tuberculosis. TB disease
usually attacks the lungs, however it can also affect almost any part of the body.
One third of the world’s population is infected with Mycobacterium tuberculosis but very
few of these people actually develop tuberculosis disease. Tuberculous infection occurs
when a person breathes in the tubercle bacilli and it lives dormantly in the lung. People
with tuberculous infection do not usually feel ill as a result of their infection—and such
cases are known as silent or latent infections. When TB infection becomes active,
usually as a result of something that weakens the body’s immune system, such as
malnutrition, HIV or excessive alcohol consumption, the symptoms can be a cough that
lasts for more than two or three weeks, weight loss, loss of appetite, fever, night sweats
and coughing up blood. Mycobacterium tuberculosis is also known as tubercle bacilli
(because they cause lesions called tubercles).  Source: UNAIDS. Link: https://data.unaids.org/pub/factsheet/2006/tb_hiv_qa.pdf. Field: Lung Disease. Disease: Tuberculosis </s>