Humans share diseases with animals. Of the 400 emerging infectious diseases identified since 1940, more than 60% have been zoonotic, meaning they have passed from animals to humans. A 2012 report found that each year zoonotic diseases account for 2.5 billion cases of human illness and about 2.7 million deaths. Lethal diseases, including Ebola and HIV, have jumped from apes to humans. Others, such as influenza and polio, have gone the opposite route, passing from humans to apes.