An alarming new symptom of Ebola in America: It seems to make brains mushy and hearts hard.

In New Jersey, two students from Rwanda, which has had no Ebola cases and is 2,800 miles from the affected countries in West Africa, are being kept home. Navarro College in Texas rejected applicants from Nigeria, initially stating that it would not accept students from countries with Ebola cases . a bit problematic because that would mean no longer accepting Americans.

The former executive director of the South Carolina Republican Party, Todd Kincannon, suggested (perhaps satirically) one way to control the disease: All people who tested positive for the Ebola virus could be “humanely put down.”Many Republicans and some Democrats have been calling for a ban on flights from the Ebola-affected West African countries. A Reuters poll indicated that almost three-quarters of Americans favored such a ban on flights.

It’s a superficially attractive idea, but also a reflection of our mixed-up notions of how to protect ourselves. The truth is that Ebola is both less serious and far more serious than we think.

It’s less serious here because, in the end, the United States and other countries with advanced health systems can suppress Ebola outbreaks. Granted, the Dallas hospital bungled its response. Still, if Nigeria and Senegal can manage Ebola successfully, so can the United States. We won’t have an epidemic here.

Yet Ebola is more serious because there is a significant risk that it will become endemic in West Africa and spin off to other countries in the region or to India, Bangladesh or China. Ebola in India would be a catastrophe.

Oxfam rightly warns that more resources are needed to prevent Ebola from becoming the “definitive humanitarian disaster of our generation.” And if the virus lingers or spreads among poor countries, it will periodically travel to America. In a globalized world, Ebola anywhere is a threat to people everywhere.

There are also security risks. Aum Shinrikyo, a Japanese terrorist group, tried to collect Ebola samples in Congo in 1992 for bioterror weapons but failed. Today, it would be easy to collect the virus, and a few suicide operatives could deliberately contract Ebola and then travel to the United States to spread the virus. (However, if the aim is mass murder, it would be simpler and probably more effective just to set off bombs.)In any case, the point is that global health is not just a warm and fuzzy kind of aid. It’s also self-interest. It’s also national security. The best way to protect ourselves is to eradicate Ebola at its source.

A flight ban would hamper that effort by making it more difficult to get health workers and supplies to Guinea, Liberia and Sierra Leone.

Dr. Peter Piot, who helped identify Ebola in 1976, tells me that flight bans would be counterproductive because they would “make aid really more difficult and expensive.”Likewise, Dr. Paul Farmer, founder of Partners in Health, tells me bluntly: “A ban would be worse than ineffective, and would certainly hamper the efforts of groups like ours . and worsen the epidemic.”Even airport screenings may be a feel-good distraction. An editorial in BMJ, a medical journal, noted that Canada used questionnaires and thermal scanners to screen hundreds of thousands of people for SARS, spent $15 million, and didn’t find a single case. The editorial suggests that airport screening “will have no meaningful effect” and that resources would be better used fighting Ebola in West Africa.

For all the fuss about our own borders, not nearly enough is being done where it counts most: in West Africa. Bravo to President Obama for pledging up to 4,000 troops to fight the disease there, but the United States and other countries must do far more . and quickly! . if Ebola is to be defeated.

The number of Ebola cases is still doubling every two to four weeks, and these countries can’t defeat the outbreak on their own. Liberia is said to have only 50 practicing doctors, according to Reuters, and there appears to be more Liberian doctors practicing in the United States than in Liberia. That brain drain means that Liberia, in effect, is providing medical foreign aid to the United States.

These are lovely countries with friendly people and some heroic health workers, but roads, electricity and other infrastructure are desperately weak. All Liberia can produce less than one-third as much electricity as the Dallas Cowboys football stadium consumes at peak times.

That’s why the American military’s help in West Africa is crucial, and why it’s a disgrace that less than half of a Sept. 16 United Nations target for Ebola response funds has been raised.

Our values and interests coincide here. So let’s calm down and get to work protecting America from Ebola by stopping this disaster at its source.