A top U.S. health official warned that if the world doesn't take action now, the Ebola virus could be the world's next AIDS.

"In the 30 years I've been working public health, the only thing like this has been AIDS, and we have to work now so that this is not the world's next AIDS," Dr. Tom Frieden, the director of the Centers for Disease Control and Prevention, said at the conference at the World Bank in Washington D.C. 

As of Wednesday, Ebola cases in the top three most affected countries - Liberia, Sierra Leone and Guinea - surpassed 8,000 reported cases of the disease, according to the World Health Organization. As of this week, the amount of affected countries in the world increased to seven after a nurse in Spain was diagnosed with the disease.

"Speed is the most important variable here," Frieden said at the conference. "This is controllable and this was preventable. It's preventable by investing in core public health services, both in the epicenter of the most affected countries, in the surrounding countries, and in other countries that might be affected."