Plague
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What is plague?
Plague is an infectious disease caused by bacteria called Yersinia pestis. These bacteria are found mainly in rodents, particularly rats, and in the fleas that feed on them. Other animals and humans usually contract the bacteria from rodent or flea bites.
Historically, plague destroyed entire civilizations. In the 1300s, the 'Black Death,' as it was called, killed approximately one-third (20 to 30 million) of Europe's population. In the mid-1800s, it killed 12 million people in China. Today, thanks to better living conditions, antibiotics, and improved sanitation, current World Health Organization statistics show there were 2,118 cases in 2003 worldwide.
How is the plague transmitted?
Yersinia pestis is found in animals throughout the world, most commonly in rats but occasionally in other wild animals, such as prairie dogs. Most cases of human plague are caused by bites of infected animals or the infected fleas that feed on them. In almost all cases, only the pneumonic form of plague (see below) can be passed from person to person.
What forms of plague are there?
Y. pestis can affect people in three different ways: bubonic, septicemic, or pneumonic plague.
What is bubonic plague?
In bubonic plague, the most common form, bacteria infect the lymph system and become inflamed. (The lymph or lymphatic system is a major component of your body's immune system. The organs within the lymphatic system are the tonsils, adenoids, spleen, and thymus.)
How is bubonic plague contracted?
Usually, bubonic plague is contracted by being bitten by an infected flea or rodent. In rare cases, Y. pestis bacteria, from a piece of contaminated clothing or other material used by a person with plague, enter through an opening in your skin.
What are the symptoms of bubonic plague?
Bubonic plague affects the lymph nodes (another part of the lymph system). Within three to seven days of exposure to the bacteria, flu-like symptoms will develop such as fever, headache, chills, weakness, and swollen, tender lymph glands (called buboes-hence the name bubonic).
Is bubonic plague contagious?
Bubonic plague is rarely spread from person to person.
What is septicemic plague?
This form of plague occurs when the bacteria multiply in the blood.
How is septicemic plague contracted?
Septicemic plague is contracted the same way as bubonic plague-usually through a flea or rodent bite. Septicemic plague also can appear as a complication of untreated bubonic or pneumonic plague.
What are the symptoms of septicemic plague?
Symptoms include fever, chills, weakness, abdominal pain, shock, and bleeding underneath the skin or other organs. Buboes, however, do not develop.
Is septicemic plague contagious?
Septicemic plague is rarely spread from person to person.
What is pneumonic plague?
This is the most serious form of plague and occurs when Y. pestis bacteria infect the lungs and cause pneumonia.
How is pneumonic plague contracted?
Pneumonic plague can be contracted in one of two ways.
* Primary pneumonic plague is contracted when plague is inhaled. This type of plague can be spread to someone else.
* Secondary pneumonic plague develops when bubonic or septicemic plague goes untreated after the disease has spread to the lungs. At this point, the disease can be transmitted to someone else.
What are the symptoms of pneumonic plague?
Within 1 to 3 days of exposure to airborne droplets of pneumonic plague, fever, headache, weakness, rapid onset of pneumonia with shortness of breath, chest pain, cough, and sometimes bloody or watery sputum develop.
Is pneumonic plague contagious?
Pneumonic plague is contagious. If someone has pneumonic plague and coughs, Y. pestis bacteria suspended in respiratory droplets is released into the air. An uninfected person can then develop pneumonic plague by breathing in those droplets.
How is plague diagnosed?
A health care provider can diagnosis plague by doing laboratory tests on blood or sputum or on fluid from a lymph node.
What are the treatment options for plague?
When the disease is suspected and diagnosed early, a health care provider can prescribe specific antibiotics, generally streptomycin or gentamycin as treatment options. Certain other antibiotics are also effective. Left untreated, bubonic plague bacteria can quickly multiply in the bloodstream, causing septicemic plague, or even progress to the lungs, causing pneumonic plague.
What are the prevention strategies for plague?
Antibiotics
Health experts recommend antibiotics if you have been exposed to wild rodent fleas during a plague outbreak in animals, or to a possible plague-infected animal. Because there are so few cases of plague in the United States, experts do not recommend taking antibiotics unless its certain there has been exposure to plague-infected fleas or animals.
Are there plague vaccines?
Currently, there is no commercially available vaccine against plague.
How Common Is Plague?
Approximately 10 to 20 people in the United States develop plague each year from flea or rodent bites-primarily from infected prairie dogs-in rural areas of the southwestern United States. About one in seven of those infected die from the disease. There has not been a case of person-to-person infection in the United States since 1924.
Worldwide, there have been small plague outbreaks in Asia, Africa, and South America.
Plague and Bioterror
Bioterrorism is a real threat to the United States and around the world. Although the United States does not currently expect a plague attack, it is possible that pneumonic plague could occur via an aerosol distribution. The Y. pestis bacterium is widely available in microbiology banks around the world, and thousands of scientists have worked with plague, making a biological attack a serious concern.
Source: National Institutes of Health
New data from University of Padua illuminate research in population research
2009 JUL 14 - (NewsRx.com) -- According to recent research published in the journal Population and Development Review, "Studies of settlements in Italy indicate that during the Early Middle Ages (6th-9th centuries) the Italian population was stagnant, whereas a slow but persistent growth followed during the High Middle Ages (10th-13th). However, the components of the dynamics of the Italian population in the long period between the Justinian Plague (around 565 in Italy) and the Black Death (1348) are largely unknown." "In this article, data from anthropometric analysis of the skeletons in 154 Italian cemeteries that date between the 1st century BCE and the 13th century are used to gain new insights on mortality of adults and nutrition. Adult mortality was higher during the Early Middle Ages than during the Roman Empire and the High Middle Ages, suggesting that the stagnation of population was determined by higher mortality. During the Early Middle Ages, however, nutritional levels were higher, as suggested by taller statures, more widespread meat consumption, and longer periods of breastfeeding," wrote I. Barbiera and colleagues, University of Padua. The researchers concluded: "We discuss some possible research lines to resolve this apparent contradiction." Barbiera and colleagues published their study in Population and Development Review (Population Dynamics in Italy in the Middle Ages: New Insights from Archaeological Findings. Population and Development Review, 2009;35(2):367+). For additional information, contact I. Barbiera, University of Padua, Dept. of Hist, I-35100 Padua, Italy. The publisher's contact information for the journal Population and Development Review is: Wiley-Blackwell Publishing, Inc., Commerce Place, 350 Main St., Malden 02148, MA, USA. Keywords: Italy, Padua, Life Sciences, Population Research, University of Padua. This article was prepared by Science Letter editors from staff and other reports. Copyright 2009, Science Letter via NewsRx.com.
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