Plague
什么是Plague？
Plague is a disease caused by the Yersinia pestis bacterium. There are three major types: bubonic plague (lymph node infection), septicemic plague (blood infection), and pneumonic plague (lung infection).
Plague continues to be a threat because of vast areas of persistent wild rodent infection.
如何获得Plague？
Plague is transmitted through bites from infected rodent fleas. Other transmission methods are less common. Plague can be transmitted by inhaling respiratory droplets from infected cats, dogs, or patients with pulmonary (pneumonic) plague when they cough or sneeze droplets into the air.
易感性和抗性
Immunity after recovering from plague is variable and depends to some extent on the amount of plague bacteria to which the person is exposed again. If large numbers of bacteria enter the body, prior infection may not always protect against re-infection.
症状是什么？
Initial symptoms include non-specific signs such as fever, chills, general fatigue, muscle fatigue, nausea, sore throat and headache. In the case of bubonic plague, the lymph nodes that drain the site of the flea bite will swell, become painful and enlarge sometimes to the size of a grapes or small limes. They often rupture through the skin and discharge pus. Untreated bubonic plague has a case-fatality rate of about 50-60 percent.
Pneumonic plague is characterized by pneumonia in the lungs and possible inflammation in the chest or excess fluid accumulating in the chest cavity.
All forms of plague may progress to septicemic plague where the infection spreads through the bloodstream to other parts of the body, including the meninges (the protective linings of the brain). Abnormal blood clotting and severe shock may occur.
Untreated pneumonic and septicemic plague are invariably fatal.
预防措施
没有可用于瘟疫的疫苗。最好的预防措施是避免与跳蚤，潜在感染的啮齿动物和其他野生动植物接触。如果在疾病暴发过程中暴露于跳蚤叮咬，则对生病之前已暴露的人给予抗生素。
处理
Plague is often misdiagnosed, especially in travellers who develop the illness after returning from an endemic area. Several classes of antibiotics are effective in treating plague. If diagnosed with plague, the patient must be isolated. The patient and their belongings must be completely rid of fleas using an insecticide effective against local fleas and safe for humans. For patients with pneumonic plague, strict isolation is necessary to prevent airborne spread until appropriate antibiotic therapy is completed and for at least 48 hours after.
药物
它常见于哪里？
野生鼠疫存在于美国西半部，南美大片地区（巴西，秘鲁，厄瓜多尔和玻利维亚），中北部，东部和南部非洲，里海附近的东南欧以及中亚和东南亚（中国，老挝，蒙古，缅甸，印度和越南）。
