The utter failure of state and federal authorities to protect two nurses who treated a Liberian Ebola patient in Texas make it seem that America’s defenses against this deadly virus have crumbled. That the Centers for Disease Control & Prevention may have told one of those nurses she could get on a plane makes it worse.

But the United States’ built-in defenses are stronger than this infection. Every Ebola patient on American soil – there are four – was infected either in Liberia or Sierra Leone or because they were treating Thomas Duncan, the Liberian patient in Dallas. Even though that nurse traveled on a plane, it’s entirely possible—and likely –that she did not infect a single person on that plane. Health officials still have plenty of opportunity to keep the virus from spreading here in the United States. And even if more people do come to the U.S. while infected with Ebola and develop symptoms here, it will still be their family members and the healthcare workers who care for them who will be at risk, not the population at large.

Despite the closure of schools in Ohio and Texas because students or staff members were on the plane with that nurse, despite the fact that people all over the country are suddenly becoming nervous about flying, your risk of catching Ebola is still far less than your risk of dying from the flu, which killed 53,667 Americans in 2010. In fact, if you’re not a healthcare worker treating an Ebola patient, it’s probably zero. The news that a potentially exposed health care worker who had gone on a cruise ship was, in fact, not infected should drive this fact home.

“This is not influenza or measles,” says Paul Offit, the Chief of the Division of Infectious Diseases at the Children’s Hospital of Philadelphia. “It’s not spread by the respiratory route. If you’re sitting next to someone on a plane, you’re not going to catch it. People should take note of the fact that Duncan’s family never got sick.”

How do we know that this virus can be corralled and controlled? Here’s a one-word answer: Nigeria.

Nigeria has already dealt with an outbreak of Ebola, and stopped it. And before delving into that outbreak, it’s worth noting that people in Nigeria constantly battle illnesses that are unheard of in America. Malaria causes one in five deaths there. It is one of just three countries where polio, the virus that paralyzed FDR’s legs, is still endemic.

This patient – known as the “index case” – was visibly sick. He collapsed on the tarmac and was helped by co-workers who supported him and helped him into a cab, and who then also developed the virus. Nigerian authorities were able to locate most of these people, but one sick patient evaded contact for several days, infecting a doctor who then transmitted the virus to his wife, his sister, and a patient.

In all, that one patient’s infection spread to 18 more people whose cases have been confirmed and one more who was suspected to have Ebola. But they were all people who had close contact with infected people. This isn’t like past infectious disease scares, like Severe Acute Respiratory Syndrome or bird flu, where there was a fear that an extremely deadly disease would spread readily through the air.

That doesn’t mean that containing an outbreak like this is easy. I learned about this outbreak from Dr. Faisal Shuaib, the technical adviser to the minister of health in Nigeria. The process he described is arduous. Anyone who was infected was given a thermometer to use daily. The moment a person registered a fever, they were evacuated immediately to a treatment center. Shuaib says that workers there looked at 900 possible infections to find those 19 confirmed cases, and they tracked many more.

This was possible, he told me, because infrastructure had put in place previously in the fight against polio, which was until then his main job. Shuaib has a position that is partly funded by the Bill & Melinda Gates Foundation, which is trying to use vaccinations to completely eradicate poliovirus. Finding patients who need vaccine and tracking those who might have Ebola were similar problems. (In Senegal, the news was even better, as a single case never transmitted the disease to anyone. )

U.S. authorities are now tasked with the same sort of detective work, and although it certainly looks messy in the age of social media, where we find out all sorts of details about their mistakes, the most important thing is that they find every case and prevent the virus from spreading. It’s true, perfect execution would have looked utterly seamless here, but this is a probably a case where, right now, a good-enough effort is going to look more disorganized and ineffective than a bad one that missed finding an infected patient.

The important thing to remember is that authorities may have to keep an eye on hundreds of people, but most of them are at very low risk for developing Ebola. The idea is not to let a single case slip through the cracks. But a lot of the steps being taken in response – for instance, like closing schools – go several steps beyond anything the CDC is likely to recommend. They are the public health equivalent of jumping at shadows.

Remember that the Ebola patient in Nigeria, who was actively sick, didn’t seem to transmit his disease to any of the passengers on the plane he traveled on. Instead, it was co-workers who were holding him who became ill. Ebola starts off being a disease more like a flu, which may be transmissible, but not easily so. Then it turns into something like cholera, something that U.S. doctors have never seen the like of, where vomit and diarrhea swarming with virus pour out of patients. It’s in this later stage when Ebola is so very easy to catch.

This is also, incidentally, why a terrorist infecting himself with Ebola and trying to act as a living bioweapon probably doesn’t make sense, despite the worries of concerned parties including Glenn Beck.

“They become so severely ill that they would be incapable of traveling,” says Pascal James Imperato, a SUNY Downstate Medical Center dean who worked for the CDC in Africa and served as the health commissioner of New York City. “If someone has fulminating vomiting and diarrhea they’re just not going to make it onto a plane. [It’s] not likely at all. And if they personally expose themselves, there is no certainty they will acquire the infection. I don’t think that’s a major risk.”

Ebola is scary, and it’s right to be angry that our response as a country has not been more streamlined and effective. But our missteps, so far, don’t create a huge amount of danger or a reason for people to feel that they or their families are at risk. Any of us are still more likely to die from the flu, from car accidents, or from firearms. That doesn’t mean we can disregard the risks that exist from Ebola. But this is the time to calmly re-assess our protective measures, not to panic. Ebola virus doesn’t travel through the air. Everyone take a nice, deep breath.