World's 10 worst disease outbreaks ever

New Delhi: Diseases have been unwanted escorts throughout the march of human history. Still throughout history mankind has suffered the crippling and mortal effects of a ravaging disease brought on by any number of target factors ranging from animals to one single human host.At times their onslaught has been so severe or concentrated that an alarming percentage of a city, country or region's population suddenly has perished. In recent years, there has been plenty of handwringing and worrying over bird flu, swine flu, and other diseases. However, the fame of swine flu may be due more to the need to fill the 24-hour news cycle than anything else.Nevertheless, there have been some serious disease outbreaks in world history.We give here a list of ten major disease outbreaks:10. The Black Death or Black PlagueThe Black Death, or The Black Plague, was one of the most deadly pandemics in human history. It probably began in Central Asia and spread to Europe by the late 1340s. The total number of deaths worldwide from the pandemic is estimated at 75 million people; there were an estimated 20 to 30 million deaths in Europe alone. The Black Death is estimated to have killed between one-third and two-thirds of Europe's population. 9. Polio Poliomyelitis, often called polio or infantile paralysis, is an acute viral infectious disease spread from person to person, primarily via the fecal-oral route. The term derives from the Greek polio , meaning “grey”, myelon , “spinal cord”, and -itis, which denotes inflammation. Although roughly 90% of polio infections are asymptomatic, affected individuals can exhibit a range of symptoms if the virus enters the blood stream. In less than 1% of polio cases the virus enters the central nervous system, preferentially infecting and destroying motor neurons, leading to muscle weakness and acute flaccid paralysis. 8. Smallpox Smallpox (also known by the Latin names Variola or Variola vera) is a contagious disease unique to humans. Smallpox is caused by either of two virus variants named Variola major and Variola minor. The deadlier form, V. major, has a mortality rate of 30–35%, while V. minor causes a milder form of disease called alastrim and kills ~1% of its victims. Long-term side-effects for survivors include the characteristic skin scars. Occasional side effects include blindness due to corneal ulcerations and infertility in male survivors. Smallpox killed an estimated 60 million Europeans, including five reigning European monarchs, in the 18th century alone. 7. Cholera Cholera (or Asiatic cholera or epidemic cholera) is an extreme diarrheal disease caused by the bacterium Vibrio cholerae. Transmission to humans is by ingesting contaminated water or food. The major reservoir for cholera was long assumed to be humans, but some evidence suggests that it is the aquatic environment. In its most severe forms, cholera is one of the most rapidly fatal illnesses known—a healthy person may become hypotensive within an hour of the onset of symptoms and may die within 2-3 hours if no treatment is provided. More commonly, the disease progresses from the first liquid stool to shock in 4-12 hours, with death following in 18 hours to several days without rehydration treatment. 6. Ebola The Ebola virus first emerged in 1976 in simultaneous outbreaks in Sudan and Zaire. It is known to be a zoonotic virus as it is currently devastating the populations of lowland gorillas in Central Africa. Despite considerable effort by the World Health Organization, no animal reservoir capable of sustaining the virus between outbreaks has been identified. However, it has been hypothesized that the most likely candidate is the fruit bat. Ebola hemorrhagic fever is potentially lethal and encompasses a range of symptoms including fever, vomiting, diarrhea, generalized pain or malaise, and sometimes internal and external bleeding. 5. Malaria Malaria is a vector-borne infectious disease caused by protozoan parasites. It is widespread in tropical and subtropical regions, including parts of the Americas, Asia, and Africa. Each year, it causes disease in approximately 515 million people and kills between one and three million, most of them young children in Sub-Saharan Africa. Malaria is commonly associated with poverty, but is also a cause of poverty and a major hindrance to economic development. Malaria is one of the most common infectious diseases and an enormous public-health problem. The disease is caused by protozoan parasites of the genus Plasmodium. 4. Bubonic Plague Bubonic plague is mainly a disease in rodents and fleas (Xenopsylla cheopsis). Infection in a human occurs when a person is bitten by a flea that has been infected by biting a rodent that itself has been infected by the bite of a flea carrying the disease. The bacteria multiply inside the flea, sticking together to form a plug that blocks its stomach and causes it to begin to starve. The flea then voraciously bites a host and continues to feed, even though it can not quell its hunger, and consequently the flea vomits blood tainted with the bacteria back into the bite wound. The bubonic plague bacterium then infects a new victim, and the flea eventually dies from starvation. Any serious outbreak of plague is usually started by other disease outbreaks in rodents, or a rise in the rodent population. 3. Cotard DelusionThis disease was described by Jules Cotard in 1880 in Paris. It is also called the Walking Corpse Syndrome. People who suffer from this rare illness think that they are dead. They often deny that they live or that the part of their body exists. There is a treatment of this mental disorder.2. Influenza Influenza, commonly known as flu, is an infectious disease of birds and mammals caused by RNA viruses of the family Orthomyxoviridae (the influenza viruses). In humans, common symptoms of influenza infection are fever, sore throat, muscle pains, severe headache, coughing, weakness and general discomfort. In more serious cases, influenza causes pneumonia, which can be fatal, particularly in young children and the elderly. Sometimes confused with the common cold, influenza is a much more severe disease and is caused by a different type of virus. Although nausea and vomiting can be produced, especially in children, these symptoms are more characteristic of the unrelated gastroenteritis, which is sometimes called “stomach flu” or “24-hour flu.” 1. AIDS Acquired immune deficiency syndrome or acquired immunodeficiency syndrome (AIDS or Aids) is a collection of symptoms and infections resulting from the specific damage to the immune system caused by the human immunodeficiency virus (HIV) in humans, and similar viruses in other species (SIV, FIV, etc.). The late stage of the condition leaves individuals susceptible to opportunistic infections and tumors. Although treatments for AIDS and HIV exist to decelerate the virus' progression, there is currently no known cure.