3.3.5　Tuberculosis

The incidence of tuberculosis（TB）has increased in recent years along with the increase of AIDSand the appearance of antibiotic resistance in the organism that causes the disease，Mycobacterium tuberculosis（MTB）（Fig.3-8）.The name tuberculosis comes from the small lesions（tubercles）that appear with the infection.The lungs and other organs are affected.The symptoms of TB include fever，weight loss，weakness，cough and，as a result of damage to blood vessels in the lungs，hemoptysis，the coughing up of sputum containing blood.TB spreads by droplets of respiratory secretions（droplet nuclei）from an infected individual when he/she coughs，laughs，or sneezes.The first time the TB organism enters the body（primary tuberculosis），the disease develops slowly.It eventually produces typical inflammatory nodules（granulomas）called tubercles.These granulomas usually remain dormant for years，during which time the patient is asymptomatic.When the immune system becomes impaired（immunocompromised）or when the patient is reexposed to the bacterium，a full-blown disease may develop.Although primarily a lung disease，TB can infect the bones，genital tract，meninges，and peritoneum.

Fig.3-8　Tuberculosis

Sputum analysis is used to isolate，stain，and identify infectious organisms.Accumulation of exudate in the alveoli may result in consolidation of lung tissue.The tuberculin test is used to test for tuberculosis infection.The test material that is used，tuberculin，is made from the byproducts of the tuberculosis organism.PPD（purified protein derivative）is the form of tuberculin commonly used.

TB is a treatable and curable disease.Active，drug-susceptible TB disease is treated with a standard 6-month course of antimicrobial drugs.(https://www.daowen.com)

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Task 7　Write a word with each of the following meanings.

Continued