Ever since Thomas Eric Duncan was diagnosed with Ebola in Dallas, there have been fears that another case will be imported from West Africa — and that the disease could potentially spread.

In response, officials have stepped up screening procedures at certain international airports, beginning with New York's John F. Kennedy International Airport.

New York City has investigated more than 80 suspected or potential Ebola cases, according to The New York Times. About one person a day has been put into isolation in a city hospital over the past six weeks.

That's a lot of scares, but no one has turned up with the actual virus.

But since many fear an outbreak in a large, global, dense city, health officials are on high alert.

How They're Preparing For A Potential Case

At JFK, the entry point for about half of the 150 people who arrive in the US each day from Guinea, Sierra Leone, or Liberia, travelers coming from or who passed through those countries will be questioned, checked for illness, and have their temperatures measured using an infrared temperature gun.

People who may have been exposed to Ebola will be referred to the CDC. If sent to a hospital, they'll probably go to Bellevue, which has been designated as the go-to place for dealing with the illness in NYC.

Bellevue Hospital in Manhattan is the go-to location for Ebola cases discovered at New York City's airports. REUTERS/Carlo Allegri The hospital currently has four isolation rooms that are set up to deal with Ebola patients, and they say they could set up nine more rooms if needed.

Failures to stop infections in Spain and Dallas show that containing the virus requires what CDC Director Tom Frieden called "meticulous attention to detail." The smallest error can have potentially fatal consequences.

One criticism of those cases is that hospital staff didn't receive adequate training on how to put on and take off gear that could be easily contaminated while dealing with the virus.

Hospital workers are training with various types of protective equipment. REUTERS/Adrees Latif Anne Bové, a representative from the New York State Nurses Association, told WNYC that in New York, "people are being trained on how to put the personal equipment on, and take it off... It's something that's done more than once or twice."

Additionally, the city's Department of Health has sent "patients" pretending to have Ebola symptoms and with a plausible travel history into all 11 city hospitals to evaluate their performance.

They've noticed that staff have a harder time removing protective suits correctly than putting them on in the first place, and they're trying to eliminate inconsistent behavior.

Healthcare workers display protective gear, which hospital staff would wear to protect them from Ebola infection, inside an isolation room as part of a media tour in the emergency department of Bellevue Hospital in Manhattan. REUTERS/Adrees Latif

The Virus Can Be Stopped

Based on the experience of Nigeria, it's clear that with the proper approach, Ebola's spread in an urban area can be stopped. Ebola cases were succesfully treated in Atlanta and Nebraska without any additional infections, which is another sign that hospitals can safely treat the disease.

But it is possible that we'll see other cases show up until the epidemic in West Africa is under control.

Until then, the CDC is telling hospitals to take a travel history of patients and if there's any chance they've been exposed, to "think Ebola."