|
|
Cancer has been around as long as humankind, but only in the second half of the twentieth century did the number of cancer cases explode.
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.
The Centers for Disease Control and Prevention (CDC) was originally known as the Communicable Disease Center, which was formed to fight malaria. It was originally headquartered in Atlanta, Georgia, since the Southern states faced the worst threat from malaria.
Long-term mental and physical effects from substance abuse include: paranoia, psychosis, immune deficiencies, and organ damage.
Most childhood vaccines are 90–99% effective in preventing disease. Side effects are rarely serious.