一篇200字左右的关于肺结核tuberculosis的英语作文

Tuberculosis is a common and often deadly infectious disease caused by mycobacteria.Tuberculosis usually attacks the lungs but can also affect the central nervous system, the lymphatic system, the circulatory system, the genitourinary system, the gastrointestinal system, bones, joints, and even the skin.

The classic symptoms of tuberculosis are a chronic cough with blood-tinged sputum, fever, night sweats, and weight loss. Infection of other organs causes a wide range of symptoms. The diagnosis relies on radiology ,a tuberculin skin test, blood tests, as well as microscopic examination and microbiological culture of bodily fluids. Tuberculosis treatment is difficult and requires long courses of multiple antibiotics. Contacts are also screened and treated if necessary. Antibiotic resistance is a growing problem in multi-drug-resistant tuberculosis. Prevention relies on screening programs and vaccination, usually with Bacillus Calmette-Guérin (BCG vaccine).

Tuberculosis is spread through the air, when people who have the disease cough, sneeze, or spit. One third of the world's current population have been infected with M. tuberculosis, and new infections occur at a rate of one per second.However, most of these cases will not develop the full-blown disease; asymptomatic, latent infection is most common. About one in ten of these latent infections will eventually progress to active disease, which, if left untreated, kills more than half of its victims.In addition, a rising number of people in the developed world are contracting tuberculosis because their immune systems are compromised by substance abuse or AIDS.

参考文献：wikipedia