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Theories Of The Black Death
Theories of the Black Death are a variety of explanations that have been advanced to explain the nature and transmission of the Black Death (1347–51). A number of epidemiologists from the 1980s to the 2000s challenged the traditional view that the Black Death was caused by plague based on the type and spread of the disease. The confirmation in 2010 and 2011 that ''Yersinia pestis'' DNA was associated with a large number of plague sites has led researchers to conclude that "Finally, plague is plague." Plague Several possible causes have been advanced for the Black Death; the most prevalent is the bubonic plague theory. Efficient transmission of ''Yersinia pestis'' is generally thought to occur only through the bites of fleas whose mid guts become obstructed by replicating ''Y. pestis'' several days after feeding on an infected host. This blockage results in starvation and aggressive feeding behaviour by fleas that repeatedly attempt to clear their blockage by regurgitation, r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Death
The Black Death (also known as the Pestilence, the Great Mortality or the Plague) was a bubonic plague pandemic occurring in Western Eurasia and North Africa from 1346 to 1353. It is the most fatal pandemic recorded in human history, causing the deaths of people, peaking in Europe from 1347 to 1351. Bubonic plague is caused by the bacterium '' Yersinia pestis'' spread by fleas, but it can also take a secondary form where it is spread by person-to-person contact via aerosols causing septicaemic or pneumonic plagues. The Black Death was the beginning of the second plague pandemic. The plague created religious, social and economic upheavals, with profound effects on the course of European history. The origin of the Black Death is disputed. The pandemic originated either in Central Asia or East Asia before spreading to Crimea with the Golden Horde army of Jani Beg as he was besieging the Genoese trading port of Kaffa in Crimea (1347). From Crimea, it was most likely carri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celsius
The degree Celsius is the unit of temperature on the Celsius scale (originally known as the centigrade scale outside Sweden), one of two temperature scales used in the International System of Units (SI), the other being the Kelvin scale. The degree Celsius (symbol: °C) can refer to a specific temperature on the Celsius scale or a unit to indicate a difference or range between two temperatures. It is named after the Swedish astronomer Anders Celsius (1701–1744), who developed a similar temperature scale in 1742. Before being renamed in 1948 to honour Anders Celsius, the unit was called ''centigrade'', from the Latin ''centum'', which means 100, and ''gradus'', which means steps. Most major countries use this scale; the other major scale, Fahrenheit, is still used in the United States, some island territories, and Liberia. The Kelvin scale is of use in the sciences, with representing absolute zero. Since 1743 the Celsius scale has been based on 0 °C for the freezing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indigenous Peoples Of The Americas
The Indigenous peoples of the Americas are the inhabitants of the Americas before the arrival of the European settlers in the 15th century, and the ethnic groups who now identify themselves with those peoples. Many Indigenous peoples of the Americas were traditionally hunter-gatherers and many, especially in the Amazon basin, still are, but many groups practiced aquaculture and agriculture. While some societies depended heavily on agriculture, others practiced a mix of farming, hunting, and gathering. In some regions, the Indigenous peoples created monumental architecture, large-scale organized cities, city-states, chiefdoms, states, Realm, kingdoms, republics, Confederation, confederacies, and empires. Some had varying degrees of knowledge of engineering, architecture, mathematics, astronomy, writing, physics, medicine, planting and irrigation, geology, mining, metallurgy, sculpture, and gold smithing. Many parts of the Americas are still populated by Indigenous peoples; ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuberculosis
Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in which case it is known as latent tuberculosis. Around 10% of latent infections progress to active disease which, if left untreated, kill about half of those affected. Typical symptoms of active TB are chronic cough with blood-containing mucus, fever, night sweats, and weight loss. It was historically referred to as consumption due to the weight loss associated with the disease. Infection of other organs can cause a wide range of symptoms. Tuberculosis is spread from one person to the next through the air when people who have active TB in their lungs cough, spit, speak, or sneeze. People with Latent TB do not spread the disease. Active infection occurs more often in people with HIV/AIDS and in those who smoke. Diagnosis of active ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smallpox
Smallpox was an infectious disease caused by variola virus (often called smallpox virus) which belongs to the genus Orthopoxvirus. The last naturally occurring case was diagnosed in October 1977, and the World Health Organization (WHO) certified the global eradication of the disease in 1980, making it the only human disease to be eradicated. The initial symptoms of the disease included fever and vomiting. This was followed by formation of ulcers in the mouth and a skin rash. Over a number of days, the skin rash turned into the characteristic fluid-filled blisters with a dent in the center. The bumps then scabbed over and fell off, leaving scars. The disease was spread between people or via contaminated objects. Prevention was achieved mainly through the smallpox vaccine. Once the disease had developed, certain antiviral medication may have helped. The risk of death was about 30%, with higher rates among babies. Often, those who survived had extensive scarring of their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Respiratory Droplet
A respiratory droplet is a small aqueous droplet produced by exhalation, consisting of saliva or mucus and other matter derived from respiratory tract surfaces. Respiratory droplets are produced naturally as a result of breathing, speaking, sneezing, coughing, or vomiting, so they are always present in our breath, but speaking and coughing increase their number. Droplet sizes range from < 1 µm to 1000 µm, and in typical breath there are around 100 droplets per litre of breath. So for a breathing rate of 10 litres per minute this means roughly 1000 droplets per minute, the vast majority of which are a few micrometres across or smaller. As these droplets are suspended in air, they are all by definition s. However, large droplets (larger than about 100 µm, but depending on conditions) rapidly fal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lymph
Lymph (from Latin, , meaning "water") is the fluid that flows through the lymphatic system, a system composed of lymph vessels (channels) and intervening lymph nodes whose function, like the venous system, is to return fluid from the tissues to be recirculated. At the origin of the fluid-return process, interstitial fluid—the fluid between the cells in all body tissues—enters the lymph capillaries. This lymphatic fluid is then transported via progressively larger lymphatic vessels through lymph nodes, where substances are removed by tissue lymphocytes and circulating lymphocytes are added to the fluid, before emptying ultimately into the right or the left subclavian vein, where it mixes with central venous blood. Because it is derived from interstitial fluid, with which blood and surrounding cells continually exchange substances, lymph undergoes continual change in composition. It is generally similar to blood plasma, which is the fluid component of blood. Lymph return ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disseminated Intravascular Coagulation
Disseminated intravascular coagulation (DIC) is a condition in which blood clots form throughout the body, blocking small blood vessels. Symptoms may include chest pain, shortness of breath, leg pain, problems speaking, or problems moving parts of the body. As clotting factors and platelets are used up, bleeding may occur. This may include blood in the urine, blood in the stool, or bleeding into the skin. Complications may include organ failure. Relatively common causes include sepsis, surgery, major trauma, cancer, and complications of pregnancy. Less common causes include snake bites, frostbite, and burns. There are two main types: acute (rapid onset) and chronic (slow onset). Diagnosis is typically based on blood tests. Findings may include low platelets, low fibrinogen, high INR, or high D-dimer. Treatment is mainly directed towards the underlying condition. Other measures may include giving platelets, cryoprecipitate, or fresh frozen plasma. Evidence to supp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Purpura
Purpura () is a condition of red or purple discolored spots on the skin that do not blanch on applying pressure. The spots are caused by bleeding underneath the skin secondary to platelet disorders, vascular disorders, coagulation disorders, or other causes. They measure 3–10 mm, whereas petechiae measure less than 3 mm, and ecchymoses greater than 1 cm. Purpura is common with typhus and can be present with meningitis caused by meningococci or septicaemia. In particular, meningococcus (''Neisseria meningitidis''), a Gram-negative diplococcus organism, releases endotoxin when it lyses. Endotoxin activates the Hageman factor (clotting factor XII), which causes disseminated intravascular coagulation (DIC). The DIC is what appears as a rash on the affected individual. Classification Purpura are a common and nonspecific medical sign; however, the underlying mechanism commonly involves one of: * Platelet disorders ( thrombocytopenic purpura) ** Primary thrombocy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sputum
Sputum is mucus that is coughed up from the lower airways (the trachea and bronchi). In medicine, sputum samples are usually used for a naked eye examination, microbiological investigation of respiratory infections and cytological investigations of respiratory systems. It is crucial that the specimen does not include any mucoid material from the nose or oral cavity. A naked eye exam of the sputum can be done at home by a patient in order to note the various colors (see below). Any hint of yellow or green color ( pus) suggests an airway infection (but does not indicate the type of organism causing it). Such color hints are best detected when the sputum is viewed on a very white background such as white paper, a white pot or a white sink surface. The more intense the yellow color, the more likely it is a caused by an infection ( bronchitis, bronchopneumonia or pneumonia). Having green, yellow, or thickened phlegm (sputum) does not always indicate the presence of an infection. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malaise
As a medical term, malaise is a feeling of general discomfort, uneasiness or lack of wellbeing and often the first sign of an infection or other disease. The word has existed in French since at least the 12th century. The term is often used figuratively in other contexts, in addition to its meaning as a general state of angst or melancholy. Cause Malaise is a non-specific symptom and can be present in the slightest ailment, such as an emotion (causing fainting, a vasovagal response) or hunger (light hypoglycemia), to the most serious conditions (cancer, stroke, heart attack, internal bleeding, etc.). Malaise expresses a patient's uneasiness that "something is not right" that may need a medical examination to determine the significance. Malaise is thought to be caused by the activation of an immune response, and the associated pro-inflammatory cytokines. Figurative use " Economic malaise" refers to an economy that is stagnant or in recession (compare depression). T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vomiting
Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting can be the result of ailments like food poisoning, gastroenteritis, pregnancy, motion sickness, or hangover; or it can be an after effect of diseases such as brain tumors, elevated intracranial pressure, or overexposure to ionizing radiation. The feeling that one is about to vomit is called nausea; it often precedes, but does not always lead to vomiting. Impairment due to alcohol or anesthesia can cause inhalation of vomit, leading to suffocation. In severe cases, where dehydration develops, intravenous fluid may be required. Antiemetics are sometimes necessary to suppress nausea and vomiting. Self-induced vomiting can be a component of an eating disorder such as bulimia, and is itself now classified as an eating disorder on its own, purging disorder. Complications Aspiration Vomiting is dangerou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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