plague - any contagious, malignant, epidemic disease, in particular the bubonic plague and the black plague (or Black Death), both forms of the same infection. These acute febrile diseases are caused by Pasteurella pestis (Yersinia pestis), discovered independently by Shibasaburo Kitasato and Alexandre Yersin in 1894, a bacterium that is transmitted to people by fleas from rats, in which epidemic waves of infection always precede great epidemics in human populations. Sylvatic plague, still another form, is carried by other rodents, e.g., squirrels, rabbits, chipmunks, in rural or wooded areas where they are prevalent.

Bubonic plague, the most common form, is characterized by very high fever, chills, prostration, delirium, hemorrhaging of the small capillaries under the skin, and enlarged, painful lymph nodes (buboes), which suppurate and may discharge. Invasion of the lungs by the organism (pneumonic plague) may occur as a complication of the bubonic form or as a primary infection. Pneumonic plague is rapidly fatal and is the only type that can be spread from person to person (by droplet spray) without intermediary transmission by flea. In the black form of plague, hemorrhages turn black, giving the term "Black Death to the disease. An overwhelming infection of the blood may cause death in three or four days, even before other symptoms appear.

In untreated cases of bubonic plague the mortality rate is approximately 60%; pneumonic plague is usually fatal if not treated within 24 hours. Such antibiotics as streptomycin and tetracycline greatly reduce the mortality rate. Vaccine is available for preventive purposes. Rodent control is important in areas of known infection.

The earliest known visitation of the plague to Europe occurred in Athens in 430 B.C. A disastrous epidemic occurred in the Mediterranean during the time of the Roman emperor Justinian; an estimated 25% to 50% of the population is reported to have succumbed. The most widespread epidemic began in Constantinople in 1334, spread throughout Europe (returning Crusaders were a factor), and in less than 20 years is estimated to have killed three quarters of the population of Europe and Asia. The great plague of London in 1665 is recorded in many works of literature. Quarantine measures helped contain the disease, but serious epidemics continued to occur even in the 19th cent. The disease is still prevalent in parts of Asia. In Surat, India, in 1994, 5,000 cases of pneumonic plague were reported in an outbreak; an estimated 100 people died, and over 400,000 people fled the city. Because the number of cases of plague has been increasing annually, it is categorized as a re-emerging infectious disease by the World Health Organization.

Characteristics:
1. also known as bubonic plague, black plague, plague
2. most deadly disease during the 1300s
3. source of infection is Yersinia pestis
4. spread via fleas, rats, humans, other organisms that carry Yersinia pestis
5. example of transmission of Yersinia pestis: It usually begins with the rat who carries the Yersinia pestis. If a flea begins feeding on the
infected rat's blood, the Yersinia pestis will multiply inside the flea's body. The Yersinia pestis clogs the flea's insides. The flea can prey on another organism [such as man] and bite them. The flea essentially regurgitates its contaminated blood onto its victim, where the Yersinia pestis will enter the new host's body through an opening, such as through the mouth or an exposed wound. If an infected person acquires pneumonia, he/she can transmit the plague to another person by coughing or sneezing.
6. factors that contributed to spread of disease: rising population, strained resources, environmental change
7. no clear accounts on exactly how many died [much conflicting data]
8. estimated that one half of Europe, North Africa, and parts of Asia's populations were lost, class, race, or age does not matter
9. disease affected all its victims equally
10. in previous centuries, physicians and assistants were baffled by the plague and at loss to find a cure or way to halt spread of plague
11. no sooner had they begun working and aiding victims were they also infected with the disease
12. worst death toll in Europe's history occurred between 1347 and 1352 - approximately one fourth of Europe's population or 25 million people had died from black death in only those five years
13. scapegoats included earthquakes, comets, lepers, Jews

Symptoms include, but not limited to:
main symptom caused by the lymph gland [buboes] - where term Bubonic is so called, appeared all over the body [especially in the groin, neck, and armpits], would swell to the size of baseballs, red spots would form on skin, when spots turned black or purple, death was inevitable, muscular pains, chills, headaches, seizures, fevers

Detection:
lab tests including blood culture, lymph node culture

Complications:
skin or physical damage, blood poisoning [septicemia]

T reatments:
1. previous treatments included subjecting victim to purging, bleeding, fumigating, bathing in urine, quarantine
2. modern treatments involve antibiotics, intravenous fluids, respiratory support
3. mortality rate is high, half of those infected will die if not treated

Protection:
1. thought to have eventually disappeared in the 1700s
2. pandemic in 1894 started in China, and infected Africa, the Pacific Islands, Australia, and the Americas through sea trades routes such as the Suez Canal
3. still occurs in Africa, South America, Australia, and Asia [not absolute]
4. has rarely attacked the United States since due to stricter checks and sanitation standards
5. vaccinations available, but not recommended because immunity is not guaranteed
6. overall, spread of black death has lessened due to the preventive measures of sanitation, rat killings, monitored transport of rats via ships