When the SARS virus spread worldwide in 2003 governments and companies quickly realized that they had very few choices for safely flying infected patients back to their home countries so that they could receive advanced medical treatment. That earlier pandemic spurred development of many more patient isolator units for air evacuations—backup options that have already helped fly home patients from the U.S., U.K. and other countries in the midst of the deadly Ebola pandemic gripping west Africa.

The first patient transport isolator for aeromedical evacuation, called the Air Transport Isolator, was developed for the U.K.'s Royal Air Force in the 1970s and also used by the U.S. military for decades. The RAF recently used the same system to fly a British Ebola patient home onboard a military transport aircraft for treatment. But the SARS outbreak prompted the U.S. Centers for Disease Control and Prevention as well as a number of private air ambulance services worldwide to develop many more isolation units capable of moving infectious disease patients under a variety of conditions. "I think the SARS situation that existed, which has been followed by avian flu and other infectious pathogens, has driven the world to the point where we’re in a very different place today," says Fraser Lamond, regional medical director of assistance and air ambulance at International SOS, a medical and travel security services company. "SARS highlighted the need for the ability to move patients by air."

The best window of opportunity for transporting Ebola patients comes when they have not yet begun showing signs of symptoms. International SOS is one of several private air ambulance services that have single-person isolation units with air filters to hold such patients who lie down during flights. But isolators must also allow accompanying medical personnel to monitor patients and provide a minimal level of treatment during the flight. "You can’t seal the patient in a bubble and administer effective treatment," Lamond says.

For instance, the single-person Air Transport Isolator used by the RAF has sleeves for intravenous tubes and glove ports for medical personnel to do work inside the isolator. The U.S. Army Medical Research Institute of Infectious Diseases also once maintained military rapid response teams that used the RAF's Air Transport Isolator, until it retired those teams in 2010. Lamond says at least four private companies other than International SOS still manufacture patient isolation units.

But smaller single-person isolation units are unable to contain Ebola patients who are at the stage of the disease where they have begun secreting infectious body fluids through vomiting or diarrhea, Lamond points out. That scenario requires a larger type of isolation unit such as the Aeromedical Biological Containment System (ABCS) developed by the CDC and private air carrier, Phoenix Air Group. The isolation unit resembles a plastic tent that has enough room for standing medical personnel—wearing protective suits—to tend to the patient. ABCS helped fly four U.S. Ebola patients home onboard special mission Gulfstream III jets operated by Phoenix. (The U.S. State Department awarded Phoenix with a $4.9-million, six-month contract for such air ambulance services starting in August.)

Public fear has surrounded the earliest air transport operations that moved Ebola patients from Africa back to their home countries such as the U.S. and the U.K. But Lamond points out that such air operations are carried out in a highly professional manner that minimizes risks and delivers the patients into the capable of hands of sophisticated health care systems. The real danger comes from Ebola patients who board commercial flights without any safeguards—which can spread the infection internationally. "If someone is moved under controlled circumstances, it's not posing a risk to public in any way I can think of," Lamond explains. "If someone travels into a country without anyone knowing about it, it's an immediate public health risk."

Having patient isolators capable of moving patients by air provides reassurance for governments, nonprofit organizations and companies that have sent personnel and employees to help contain the Ebola outbreak in Africa. Still, the air transport operations only serve as an emergency backup option for those individuals rather than a major solution for stopping the current pandemic. "Very few cases are going to be moved," Lamond says. "The real solution is finding robust solutions on the ground."

More Ebola coverage:
Fact or Fiction?: The Ebola Virus Will Go Airborne
Ebola Doctor Reveals How Infected Americans Were Cured
Motorcycling to Ebola Treatment Could Spread the Infection
In-depth report: Ebola: What You Need to Know

Additional reporting was provided by Nicholas St. Fleur.