This means that Hairy cell leukemia, or a subtype of Hairy cell leukemia, affects less than 200,000 people in the US population. Ophanet, a consortium of European partners, currently defines a condition rare when it affects 1 person per 2,000. They list Hairy cell leukemia as a rare disease.
In fact, some of the oldest alphabetic symbols have been found in Central America (2,500 years ago), China (more than 3,000 years ago), and the Middle East (more than 5,000 years ago). One of the earliest forms of the alphabet was hieroglyphics. Hieroglyphics were single symbols that stood for entire words.
As a mathematical device, the infinity sign was first discovered in 1655 by John Wallis, but its significance as a religious symbol is much older. The infinity sign has its origins in the Arabic numerals that actually came from India in the first place.