12 Deadly Diseaes Cured in the 20th Century, 4-5

The death rate for malaria and the measles, once universally life-threatening illnesses, has dropped dramatically as a result of cures created in the last 100 years.

4. Malaria

This disease is a parasitic infection of the liver and red blood cells. In its mildest forms it can produce flu-like symptoms and nausea, and in its severest forms it can cause seizures, coma, fluid buildup in the lungs, kidney failure, and death. The disease is transmitted by female mosquitoes of the genus Anopheles. When the mosquito bites, the parasites enter a person's body, invading red blood cells and causing the cells to rupture. As the cells burst, they release chemicals that cause malaria's symptoms.

About 350 million to 500 million cases of malaria occur worldwide every year. About one million are fatal, with children in sub-Saharan Africa accounting for most of the deaths. Other high-risk areas include Central and South America, India, and the Middle East. Malaria is treated with a variety of drugs, some of which kill the parasites once they're in the blood and others that prevent infection in the first place. Of course, if you can avoid the parasite-carrying mosquitoes, you can avoid malaria, so the disease is often controlled using mosquito repellent and bed netting, especially in poor countries that cannot afford medications.

5. Measles

Measles is a highly contagious viral illness of the respiratory system that spreads through airborne droplets when an infected person coughs or sneezes. Although the first symptoms of measles mimic a simple cold, with a cough, runny nose, and red watery eyes, this disease is more serious. As measles progresses, the infected person develops a fever and a red or brownish-red skin rash. Complications can include diarrhea, pneumonia, brain infection, and even death, although these are seen more commonly in malnourished or immunodeficient people. Measles has historically been a devastating disease, but WHO reported in 2006 that measles mortality rates dropped from 871,000 to 454,000 between 1999 and 2004, thanks to a global immunization drive.

Until 1963, when the first measles vaccine was used in the United States, almost everyone got the measles by age 20. There has been a 99 percent reduction in measles since then, but outbreaks have occurred when the disease is brought over from other countries or when children don't get the vaccine or all the required doses. Most children today receive the measles vaccine as part of the MMR vaccination, which protects against measles, mumps, and rubella (German measles).

Read on to learn about a couple more obscure but often deadly illnesses: pneumococcal disease and whooping cough -- both of which have been cured in the 20th century thanks to science.