Wiped Out At the beginning of the 20th century, worldwide life expectancy was less than 40 years of age. Today the world average stands at around 70. The single biggest reason for this miraculous leap in longevity has been our ability to cure diseases. Vaccines, antibiotics and advances in medical technology have changed the game. We are still in an arms race against many diseases, but we stand at a unique period in human history where it's possible to imagine a day when we have conquered disease. Cures have been found for several of history's most feared diseases, and a few diseases have been eradicated. Here's our list of deadly diseases cured by modern science. Tetanus Though most commonly associated with rust and infections caused by rusty nails, tetanus is actually not caused by rust itself. Rather, tetanus comes from the bacterium Clostridium tetani, the spores for which can often be found on rusty surfaces. The disease is characterized by painful muscle spasms, most often in the jaw (thus the term "lockjaw"). Luckily, the disease can be prevented with regular vaccination. In places where regular tetanus shots are given, such as in the United States, the disease has been nearly eliminated. According to the CDC, only 233 cases of tetanuswere reported in the United States between 2001 and 2008, mostly the fault of people late to get their scheduled booster shot. This photo shows a child after being vaccinated in Lobaye, Central African Republic. Rabies Capable of being transmitted across the species barrier, usually through biting, rabies is a threat to virtually every species of mammal. It is characterized by nervous system conditions such as excitation, paranoia, anxiety, confusion and even fear of water. Hypersalivation is also a common symptom, making the sight of any animal foaming at the mouth a terrifying experience. The good news is, the disease can be prevented by vaccination, even if the injection occurs shortly after initial infection. Since it is most commonly transmitted via biting, there's usually little doubt about when transmission occurs. Though the disease can be difficult to control among wild animals, it has been successfully eliminated from the dog population in the United States. Polio The triumph over polio is one of the great success stories of modern medical science. Once among the most dreaded of childhood diseases, it has now been eradicated throughout most of the developed world. Though epidemics do still occur in the developing world, a global eradication campaignremains underway. A polio-free world is likely only a few years from becoming a reality. One of the most famous people to have had polio was President Franklin Delano Roosevelt, who was diagnosed with the disease when he was 39. He is shown here at the Yalta Conference in 1945 with British Prime Minister Winston Churchill (left) and Soviet leader Joseph Stalin. Yellow fever Transmitted by mosquitoes, yellow fever gets its name from the yellowing of the skin and eyes (or jaundice) that is a symptom of infection. Jaundice is also an indication of liver damage, which can lead to death. Though there is no known treatment for the disease once it is contracted, it can be completely prevented through vaccination. Today it has been eliminated from the United States, but still occurs in tropical South America and Africa. Travelers to these regions are often required to get the vaccine. Rinderpest Rinderpest is essentially the cattle equivalent of the measles virus. Though it is not a danger to humans (it only afflicts cattle and other ruminants, such as buffalo and deer), the virus has nevertheless been a major threat to humanity because of our reliance on these creatures as farm animals. After a vaccine was developed, the disease was targeted for global eradication by the World Organization for Animal Health in 1994. The last confirmed case of the disease was in 2001, and in 2011 was officiallydeemed eradicated. Whooping cough Named after the "whooping" sounds made during the uncontrollable coughing symptomatic of this disease, whooping cough is caused by the highly contagious Bordetella pertussis bacteria. Coughing fits can often last for weeks. Though the disease can be completely prevented through vaccination, it has tragically made a comeback in recent years. Measles Most commonly characterized by a rash that begins on the face and spreads throughout the body, measles is a serious condition that can lead to brain infection and death. Though historically a devastating disease, it has experienced steep decline ever since the early 1960s, when the measles vaccine was first developed. Today it is administered to most children in the United States via the MMR vaccination. In 2011, 222 measles cases were reported in the United States, the highest level in 15 years. Previous to that, only about 50 cases of measles were reported annually in the U.S., most of which were contracted outside of the country. This thin-section transmission electron micrograph (TEM) shows a single virus particle, or virion, of measles virus. Smallpox Responsible for an estimated 300 million to 500 million deaths during the 20th century alone, smallpox has been one of humanity's most merciless scourges. The virus primarily attacks skin cells, which leads to characteristic bumps, or macules, that form all over the body. The smallpox vaccine was the first successful vaccine to be developed. It was discovered by Edward Jenner in 1796, after he noticed that people who caught the more innocuous cowpox virus seemed to be immune to the smallpox virus. A worldwide eradication campaign in the 20th century eventually led to the destruction of the smallpox virus. To this day, it remains the only virus that afflicted humans that has been 100 percent eradicated. The last known case of the disease occurred in Somalia in 1977. Source
