Recent swings in the U.S. stock market are violent. The Dow Jones Industrial Average, one indicator of how the whole market is doing, closed down 173 points yesterday. At one point, it had dropped 460 points. We`ve told you how when investors are afraid, they tend to sell, dropping the value of stocks in the market. What are they afraid of?For one thing, Germany. Europe`s largest economy isn`t doing well. For another American retail sales decreases, and so did prices. Those are bad signs for the economy`s health.Another reason investors are fearful, the possible spread of the deadly Ebola virus in the U.S. A second nurse at a Dallas Texas Hospital has contracted the disease. Like Nina Pham, whom we told you about earlier, 29-year old Amber Vincent helped treat a Liberian man who died last week from Ebola. Vincent had traveled to Ohio recently. The CDC says, she wasn`t officially allowed to travel on a commercial plane, but it says the risk to others is low since Vincent didn`t have symptoms when she went.

Meanwhile, America`s largest nurses` union is strongly criticizing health officials, including the CDC over how they`ve handled Ebola. It says the Dallas nurses didn`t have the supplies or the training they needed and that they feel lied to and deserted to handle their own situation.

The CDC says it`s committed to the nurses` safety and giving them what they need to safely manage Ebola patients.

Also, President Obama postponed a Democratic campaign trip yesterday. Instead, he met with cabinet agencies to discuss the government`s response to Ebola.

One thing that`s spreading faster than the disease is the fear of it.

A scene out of a disaster movie. First responders in hazmat gear board an Emirates` flight from Dubai and check five passengers with flu-like symptoms. None met the criteria for Ebola or had visited Africa.

At LAX, 40 firefighters respond to a passenger with flu-like symptoms. But that`s where the scare ends.

It has turned out that there was some miscommunication that this patient had been to the continent of Africa, but not near West Africa.

Ebola has not, repeat, not, spread through the U.S., but fear certainly has. In Nashville, Tennessee, a sick passenger was taken of the plane that originated in Dallas. The patient has no contact with anyone with Ebola or traveled to Africa.

In Richmond, Virginia, a patient with a low grade fever who had traveled to Africa is isolated. Even though the clinic says they don`t believe it`s Ebola.

Each scare stretches first responders and can cost taxpayers thousands of dollars and flu season has barely begun.

People will take this one in stride, but it takes a while. It takes longer if you tell them they are panicking.

What makes this societal learning curve war, says Sandman, is early on. The CDC chief insisted everything was under control, then the nurse in Dallas contracted the disease.

What he didn`t say is it`s going to be harder than people imagine. It`s going to be harder than we imagine. So, now, yeah, now people are angry at the CDC and that anger is sort of morphing into fear.