10 Diseases That Used to Be Death Sentences

A veterinarian checks a dog's heartbeat before giving it a rabies vaccine injection at a community office in Beijing, China in 2007. That year, rabies topped the list of fatal infectious diseases in China for several months. China Photos/Getty Images

If you're ever bitten by a dog, bat, raccoon or other angry animal, you should hustle to a hospital with haste. Even if the animal is more bad-tempered than rabid, this disease isn't something you want to take a chance on. Once symptoms appear, rabies is transformed into a painful illness that fatally attacks the central nervous system, causing confusion and delirium and eventually death [source: CDC].

However, rabies is very treatable as long as it's caught before symptoms emerge [source: Humane Society]. Most people know when they've been bitten by an animal, making the risk easy enough to assess, and post-exposure treatments and vaccines are available to stop symptoms before they start [source: CDC]. Awareness and treatment are credited with keeping the U.S. death toll at two or three people per year, down from 100 in the early 1900s [source: CDC].