Allen, the co-founder of Microsoft , got involved with the Ebola battle over the summer, donating more than $20 million to organizations like the American Red Cross, UNICEF and CDC Foundation and launching the Tackle Ebola campaign. His latest gift eclipses his previous efforts and is the largest known individual contribution so far, though he’s in good company with other notably philanthropic billionaires. Last week Mark Zuckerberg and his wife Priscilla Chan announced a $25 million pledge to the Centers for Disease Control Foundation; on Sept. 10 Bill and Melinda Gates donated $50 million through their foundation to aid emergency efforts in Ebola stricken areas. Aliko Dangote, Africa’s richest man, and other ultra-wealthy Nigerians have donated to stop the disease’s spread in Africa, and just this week Nigeria was declared Ebola free.

There are nearly 10,000 Ebola cases in Guinea, Liberia and Sierra Leone, where more than 4,800 people have died from the disease, according to the World Health Organization.
“The Ebola virus is unlike any health crisis we have ever experienced and needs a response unlike anything we have ever seen,” Allen said in the announcement. “To effectively contain this outbreak and prevent it from becoming a global epidemic, we must pool our efforts to raise the funds, coordinate the resources and develop the creative solutions needed to combat this problem. I am committed to doing my part in tackling this crisis.”
Although the disease has garnered frenzied attention in developed nations like the United States, confirmed Ebola cases have been all but nonexistent within these countries. The United States has had three cases and one death, according to the Centers for Disease Control and Prevention, although news broke today that a doctor who spent time in West Africa is being tested for the virus at a New York hospital.
Allen, whose net worth is $17 billion, has given away over $1.5 billion, including a half billion to his Allen Institute for Brain Science, which studies the brain’s connections with health and disease.