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Giardia is one of the most common intestinal parasites worldwide, and infects up to 20% of the world population, mostly in poorer countries with inadequate sanitation. Infections are most common in children, though chronic Giardia is more common in adults.
In 1844, Charles Goodyear obtained the first patent for a rubber condom.
Cucumber slices relieve headaches by tightening blood vessels, reducing blood flow to the area, and relieving pressure.
More than 2,500 barbiturates have been synthesized. At the height of their popularity, about 50 were marketed for human use.
A cataract is a clouding of the eyes' natural lens. As we age, some clouding of the lens may occur. The first sign of a cataract is usually blurry vision. Although glasses and other visual aids may at first help a person with cataracts, surgery may become inevitable. Cataract surgery is very successful in restoring vision, and it is the most frequently performed surgery in the United States.