Doctor who survived Ebola said he knows the fear of being infected

“I was lucky enough to survive," said Dr. Craig Spencer.

Dr. Craig Spencer, who was infected with Ebola when treating patients in an outbreak in 2014 , tells ABC News he is “certain” the current outbreak is “much bigger” than what current numbers show.

"My biggest concern about this outbreak is that we learned way too much way too quickly for this to be anything but really bad,” Spencer said.

Spencer, who remains an ER doctor and is now also a public health professor at Brown University, tested positive for Ebola after treating patients in Guinea with Doctors Without Borders in 2014. Upon arrival to the U.S., he spent 19 days being treated at Bellevue Hospital in Manhattan.

“I was lucky enough to survive. And then a few months later, I went back to Guinea. As an epidemiologist helping run the national response for Doctors Without Borders in early 2015,” Spencer said.

Spencer says that the U.S. government pulling out of its historically prominent role in global health has left it flat footed in responding to this outbreak.

"I'm an emergency physician. I don't want to know who my team is and meet them for the first time at the start of my shift,” Spencer said.

Spencer said he was thinking of the American doctor who was recently infected with Ebola treating patients in the Democratic Republic of the Congo.

"I unfortunately know exactly what it feels like to be in that situation, to be incredibly fearful, to have a disease that maybe you've seen the impact of and know that there's not a treatment for. I'm thinking of him and his family,” Spencer said.

When asked if he would ever consider going back to an Ebola outbreak, he said he would be happy to help.

"I've already put my family through quite a bit. We'll see what comes out of this, but I'm happy to help,” Spencer said.