Plague pandemics

Despite the remarkable natural defence mechaifisms that have evolved, they have not always been successful and infections have, on occasions, produced catastrophic effects on the human population (Box 17.6). Two examples are the plague pandemic of the mid-1300s (Box 17.7), and the influenza pandemic of the early 1900s. This is due, in part, to the ability of the pathogen to avoid detection or killing by the immune system. 

The third, or modern, plague pandemic arose in 1894 in China and spread throughout the world via modern transportation.1216 It was also in 1894 that... 

Influenza has plagued humankind since the dawn of history and continues to affect a significant proportion of the population irrespective of age or previous infection history. These periodic epidemics that reinfect otherwise healthy people have devastated communities world wide. Some pandemics like the 1917-1919 Spanish flu were responsible for the death of tens of millions of people throughout the world. The origins, spread, and severity of influenza epidemics have been a puzzle that has only in the last two decades been adequately addressed. In early times it was thought that the disease was the evil influence (sic) of the stars, and other extraterrestial objects. At present it is generally accepted that the disease is of viral origin, spread by aerosols produced by infected animals, and the continual production of new strains of the virus results in reinfection of the disease (reviewed in Reference 1). 

Plague is possibly the most feared infectious disease in the history of humankind. More than 200 million people have died from plague. In its most notorious manifestation, the so-called Black Death of the Middle Ages, plague was responsible for a pandemic that affected Europe between the 8th and 14th centuries, decimating nearly 40% of the population (McGovern Friedlander, 1997). 

It is probably a relatively recent recognition that one of the great factors in shaping human history has been infectious disease. Almost whole populations may have disappeared from the map. Bubonic plague killed one-third of Europe s population in the fourteenth century. The first documented pandemic was in the early sixth century. It began in northeast Africa (Egypt and Ethiopia) and spread through Europe. It lasted 60 years and is estimated to have killed 100 million people. Smaller epidemics continued up to the end of the nineteenth century. 

Plague has been one of the worst human pandemics throughout history. Its use as a biological warfare agent, however, is not known. The disease is attributed to the bacteria Yersinia pestis, and caused mostly from bites of rat flea. The animals that transmit this disease are mostly black rats and the rock and ground squirrels. When the flea bites an infected animal the bacteria enter into the body of the flea and multiply inside. When the infected flea attempts to bite again it vomits clotted blood and bacteria into the bloodstream of the victim, either human or a small mammal, usually rat. Thus the disease is mostly transmitted from rodents from the bites of infected fleas. 

Alexandre J. E. Yersin discovered that Yersinia pestis satisfied Koch s postulates for bubonic plague.17 The reservoir of plague bacilli in the fleas of the Siberian marmot was likely responsible for the Manchurian pneumonic plague epidemic of 1910-1911, which caused 50,000 deaths.2 The modern pandemic arrived in Bombay in 1898, and during the next 50 years, more than 13 million Indians died of plague.2,18... 

During the modern pandemic, W. G. Liston, a member of the Indian Plague Commission (1898— 1914), made the association of plague with rats and incriminated the rat flea as a vector.2 Subsequently, more than 200 species of animals and 80 species of fleas have been implicated in maintaining Y pestis endemic foci throughout the world.21... 

Plague is a zoonotic infection caused by the Gram-negative bacillus Yersinia pestis. Three great human pandemics have been responsible for more deaths than any other infectious agent in history. Plague is maintained in nature, predominantly in urban and sylvatic rodents, by a flea vector. Humans are not necessary for persistence of the or-... 

It wasn t the bubonic plague, typhoid, smallpox, or AIDS. It was the flu pandemic of 1918. 

The Spanish flu pandemic of 1917 to 1919 has been called by some in the pre-HIV age as "the last great plague." The middle estimate of the worldwide death toll was approximately twenty million lives lost to the illness in that era. Perhaps as many as 500 million people had the illness commonly known as "grippe." Although other plagues had higher death rates, in terms of sheer numbers, the Spanish flu pandemic is credited as one of the worst, if not the worst In the United Stales, one person in eveiy four [approximately twenty million cases] became ill with the flu. 

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