A report last week from the Centers for Disease Control and Prevention posed two very different scenarios of how the Ebola outbreak in two West African countries could play out during the next months.

One envisions that by January, Sierra Leone and Liberia, the countries hardest hit by the virus, will be starting to get back to normal, pre-outbreak life.

The other scenario is truly chilling: 21,000 cases this week, 1.4 million people infected by Jan. 20 and the beginning of a long battle against this extremely deadly disease.

Imagine — 1.4 million people sick with a virus that kills between half and 70 percent of the people infected.

The CDC came up with those scenarios by extrapolating the outbreak of the hemorrhagic disease since March. It refers to the latter as the worst-case scenario, though, we all know it’s really just the best of the worst-case scenarios.

The models used by the CDC looked at things we know.

Currently and officially, about 6,000 people have been infected and about half have died. According to the CDC report, new cases of Ebola reported in Sierra Leone are doubling in number approximately every month; in Liberia, they are doubling every 15 to 20 days.

There are the things we don’t know. For instance, how many people are infected with the virus that have not been reported. The World Health Organization, in its own bleak Ebola report also released last week, acknowledged that the real tally of those infected and dead from the outbreak is probably vastly underreported.

And then there are the things we don’t want to think about: The Ebola virus has been mutating throughout the outbreak. The longer it lasts, it could mutate in some way that makes it easier to transmit the disease or more deadly.

All of this points to one undeniable fact: How the world responds right now to the Ebola infection will make the difference between the best-case scenario, the worst-case scenario and the scenario so grim we don’t want to even consider it.

CDC Director Thomas R. Frieden told the New York Times that a “surge” of health care and other resources could “break the back” of the Ebola outbreak.

Recently, President Barack Obama committed money and 3,000 troops to fight the epidemic by building hospitals and other health care infrastructure in West Africa. But $1 billion to fund the effort is being held up by Republican Sen. Jim Inhofe of Oklahoma in the Senate Armed Services Committee until the president presents a plan to protect the troops. Inhofe is playing politics with a deadly outbreak and needs to release the money now.

The rest of the world, especially the larger countries — China, Russia, India — must commit resources, too. We can put past grievances aside to work together to quell the viral danger where it lives now, or wait until it reaches our own borders.

Dr. Margaret Chan, the director-general of WHO, put it bluntly in a speech to the U.N. Security Council last week asking for more resources to fight the epidemic.

“None of us experienced in containing outbreaks has ever seen, in our lifetimes, an emergency on this scale, with this degree of suffering, and with this magnitude of cascading consequences.” If that’s not a call to action, nothing is.

— Sacramento (Calif.) Bee