Bubonic plague natural history: Difference between revisions

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Plague has a remarkable place in history. For centuries, plague represented disaster for those living in Asia, Africa and Europe, where, it has been    said, populations were so affected that sometimes there were not enough people left alive to bury the dead. Because the cause of plague was unknown, plague outbreaks contributed to massive panic in cities and countries where it appeared.
#Redirect [[Yersinia pestis infection natural history, complications and prognosis]]
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===Perspective and history===
Plague has a remarkable place in history. For centuries, plague represented        disaster for those living in Asia, Africa and Europe, where, it has been        said, populations were so affected that sometimes there were not enough        people left alive to bury the dead (Gross, 1995). Because the cause of        plague was unknown, plague outbreaks contributed to massive panic in cities        and countries where it appeared. The [[disease]] was believed to be delivered        upon the people by the displeasure of the gods, by other supernatural        powers or, by heavenly disturbance. Innocent groups of people were blamed        for spreading plague and were persecuted by the panicked masses. Numerous        references in art, literature and monuments attest to the horrors and        devastation of past plague [[epidemics]]. So imprinted in our minds is the        fear of plague that, even now, entering into the 21st century, a suspected        plague outbreak can incite mass panic and bring much of the world's economy        to a temporary standstill. The number of human plague infections is low        when compared to diseases caused by other agents, yet plague invokes an        intense, irrational fear, disproportionate to its [[transmission]] potential        in the post-[[antibiotic]]/[[vaccination]] era.
 
===Fundamental works===
 
The fundamental but separate works by Yersin and Kitasato in        1894 on the discovery of the etiologic agent of plague in Hong Kong opened        the way for investigating the [[disease]] and how it is spread. Kitasato and        Yersin described, within days of each other’s findings, the presence        of [[bipolar]] staining [[organisms]] in the [[swollen]] [[lymph node]] ([[bubo]]), [[blood]],        [[lungs]], [[liver]] and [[spleen]] of [[dead]] patients (Bibel et al., 1976). Cultures        isolated from patient specimens were [[inoculated]] into a variety of laboratory        animals, including mice. These animals died within days after [[injection]],        and the same bacilli as those found in patient specimens were present        in the animal [[organs]]. Though both investigators reported their findings,        there were a series of confusing and contradictory statements by Kitasato        that eventually led to the acceptance of Yersin as the primary discoverer        of the organism now named after him, Yersinia         pestis (Bibel et al., 1976). Yersin had recorded that rats were        affected by plague not only during plague epidemics but also often preceding        such epidemics in humans. In fact, plague was designated, in local languages,        as a disease of the rats: villagers in China, India and Formosa (Taiwan)        described that when hundreds and thousands of rats lie dead in and out        of houses, plague outbreaks in people soon followed (Gross, 1995). The        transmission of plague was described by Simond in 1898. He noted that        persons who became ill did not have to be in close contact with each other        to acquire the [[disease]]. In Yunnan, China, inhabitants would run away from        their homes as soon as they saw dead rats. On the island of Formosa, residents        considered handling dead rats a risk for developing plague. These observations        led Simond to suspect that the flea might be an intermediary factor in        the transmission of plague since people acquired plague only if they were        in contact with recently dead rats and were not affected if they touched        rats that were dead for more than 24 hours. Simond demonstrated that the        rat flea (Xenopsylla cheopis) transmitted the disease in a now        classic experiment in which a healthy rat, separated from direct contact        with a recently plague-killed rat, died of plague after the infected fleas        jumped from the first rat to the second.
 
===Ancient disease===
 
Plague is an ancient [[disease]] that is not likely to disappear;        its continued outbreaks throughout the world attest to its tenacious presence.        Since the first descriptions, many studies have examined the [[transmission]],        [[bubonic plague epidemiology and demographics|epidemiology]] and [[pathogenesis]] of the disease (Gage, 1998). Plague is a        [[bacterial infection]] of small mammals transmitted from animal to animal        by the [[bite]] of infected fleas. Plague cycles naturally in its [[enzootic        foci]], circulating between small mammals and fleas without human involvement.        The quiescent periods, during which few or no human cases are detected,        may last for years, leading to mistaken declarations of plague eradication.        However long the silent periods last, plague may suddenly reappear. The        combination of false assurance of its eradication, and the failure of        public health vigilance, sets the stage for the panic that may ensue when        enzootic plague spills over from its natural cycle into the peridomestic        and commensal rodent populations (and their fleas), bringing plague into        closer human contact. Poor [[sanitation]], overcrowding and high numbers of        rodents are conditions that enhance urban plague transmission. Thus, a        plague outbreak has come to represent an indictment of social, environmental        and political changes in the modern world.
 
==References==
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Latest revision as of 02:29, 26 July 2014