US President Barack Obama urged Congress on Tuesday to approve $6.18 billion to help fight the Ebola outbreak, reminding them that even though the story has faded from the headlines, the battle against the virus is far from over."Every hotspot is an ember that if not contained can become a new fire, so we cannot let down our guard even for a minute," Obama said. "And we can't just fight this epidemic. We have to extinguish it."Obama toured a lab at the National Institutes of Health, where a team of researchers last week published promising results from the first phase of a research trial for an Ebola vaccine.Obama said the United States needs to continue to fund basic research and help nations such as Guinea, Liberia and Sierra Leone build better public health systems so that the world can quickly contain future disease outbreaks."It is a smart investment for us to make. It's not just insurance. It is knowing that down the road we're going to continue to have problems like this, particularly in a globalized world where you move from one side of the world to the other in a day," Obama said.