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Astigmatism is the most common vision problem. It may accompany nearsightedness or farsightedness. It is usually caused by an irregularly shaped cornea, but sometimes it is the result of an irregularly shaped lens. Either type can be corrected by eyeglasses, contact lenses, or refractive surgery.
Methicillin-resistant Staphylococcus aureus or MRSA was discovered in 1961 in the United Kingdom. It if often referred to as a superbug. MRSA infections cause more deaths in the United States every year than AIDS.
Bacteria have flourished on the earth for over three billion years. They were the first life forms on the planet.
The human body produces and destroys 15 million blood cells every second.
In 1835 it was discovered that a disease of silkworms known as muscardine could be transferred from one silkworm to another, and was caused by a fungus.