There are five known strains of the Ebola virus, and the 2014 outbreak happens to involve the Zaire strain, which is the most potent and deadly form of the disease. In those who are affected by the disease, fatality rates can be as high as 90 percent, and they can pass the infection on to other around them via bodily fluids such as sweat, blood, tears, and vomit. Ebola can even be carried in a patient's semen for up to seven weeks after the infection has cleared.
Ebola causes death by lowering blood pressure, which prompts organs to fail, and the immune system to be severely weakened. And while there's still no proven vaccine or cure for the disease, patients have survived when their dehydration is treated and antibiotics are used to ward off secondary infections.