<P> Bubonic plague is one of three types of plague caused by bacterium Yersinia pestis . One to seven days after exposure to the bacteria, flu like symptoms develop . These include fever, headaches, and vomiting . Swollen and painful lymph nodes occur in the area closest to where the bacteria entered the skin . Occasionally the swollen lymph nodes may break open . </P> <P> The three types of plague are the result of the route of infection: bubonic plague, septicemic plague, and pneumonic plague . Bubonic plague is mainly spread by infected fleas from small animals . It may also result from exposure to the body fluids from a dead plague - infected animal . In the bubonic form of plague, the bacteria enter through the skin through a flea bite and travel via the lymphatic vessels to a lymph node, causing it to swell . Diagnosis is made by finding the bacteria in the blood, sputum, or fluid from lymph nodes . </P> <P> Prevention is through public health measures such as not handling dead animals in areas where plague is common . Vaccines have not been found to be very useful for plague prevention . Several antibiotics are effective for treatment, including streptomycin, gentamicin, and doxycycline . Without treatment, plague results in the death of 30% to 90% of those infected . Death, if it occurs, is typically within ten days . With treatment the risk of death is around 10% . Globally there are about 650 documented cases a year, which result in ~ 120 deaths . In the 21st century, the disease is most common in Africa . </P> <P> The plague is believed to be the cause of the Black Death that swept through Asia, Europe, and Africa in the 14th century and killed an estimated 50 million people . This was about 25% to 60% of the European population . Because the plague killed so many of the working population, wages rose due to the demand for labor . Some historians see this as a turning point in European economic development . The term bubonic is derived from the Greek word βουβών, meaning "groin". The term "buboes" is also used to refer to the swollen lymph nodes . </P>

When was the cure for the bubonic plague found
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