Bubonic Plague
Bubonic plague is the disease that is believed to be the
cause of the Black Death 1347-1351. The Black Death covered Eurasia
and killed more than 237 million people. Bubonic Plague is caused my the
Bacteria Yersinia pestis. Y. pestis thrives in rats. It is transmitted to
humans through a vector, fleas.
Rat fleas, Xenopsylla cheopis. who feed on rats infected with Y. pestis take
the bacteria into their stomachs. The bacteria while in the flea’s multiply and
form a plug to block the stomach of the flea and make it very hungry. The flea
being very hungry tries to find many hosts. When it finds a host, a human or
another rat or other mammal, it bites the host and tried to suck blood. But the
bacteria have blocked its stomach so the flea feels an urge to vomit. The flea
vomits and Y. pestis is transmitted to the blood stream of the host. The flea
cannot satisfy its hunger and finds more hosts until it dies of starvation.
Once infected, the bacteria infect the Lymph nodes and cause
inflammation. This is why it is called bubonic plague because the lymph nodes
cause “bubo” or bumps to be formed. The lymph nodes become necrotic, hemmorage
and the infection spreads. Bubonic plague commonly results in Acral necrosis
which causes bleeding beneath the skin because of hemmoraging. Red blood cells
are lying outside of their caplillaries the effected regions turn black and
damage tissues. many people believe
that this is what the black death is named for. But it is actually named for
the figurative sense of black meaning bleak, dreadful and lugubrious for which
were the condition experienced by people during the plague.
Bubonic plague shows signs of symptoms 3-7 days after
infection. First Symptoms are chills, fever diarrhea headaches and swelling of
lymph nodes. If untreated the mortality rate is 30-75%.
