|
|
Fungal nail infections account for up to 30% of all skin infections. They affect 5% of the general population—mostly people over the age of 70.
About 3.2 billion people, nearly half the world population, are at risk for malaria. In 2015, there are about 214 million malaria cases and an estimated 438,000 malaria deaths.
For about 100 years, scientists thought that peptic ulcers were caused by stress, spicy food, and alcohol. Later, researchers added stomach acid to the list of causes and began treating ulcers with antacids. Now it is known that peptic ulcers are predominantly caused by Helicobacter pylori, a spiral-shaped bacterium that normally exist in the stomach.
The horizontal fraction bar was introduced by the Arabs.
There are over 65,000 known species of protozoa. About 10,000 species are parasitic.