TORONTO -- The unprecedented spread of the Ebola virus in West Africa may be pushing the world toward a viral disaster, a commentary published in Friday's New York Times suggests.

The article reveals that experts are worried ongoing transmission of the virus through people runs the risk of giving rise to mutations that might allow Ebola to spread through the air, like some of the world's most contagious viruses. The virus currently spreads when a person has contact with contaminated bodily fluids.

The article bears the headline: What We're Afraid to Say About Ebola. It was written by Michael Osterholm of the University of Minnesota's Center for Infectious Diseases Research and Policy.

It is among the first signs that experts who have been watching the outbreak with mounting alarm are ready to go public with grave concerns about an Ebola outbreak that is unlike any the world has ever seen.

To date nearly 4,800 people have been infected and roughly 2,400 have died, the World Health Organization said Friday. The global health agency has repeatedly cautioned that its numbers are likely an underestimate.

A few weeks back the WHO warned that 20,000 people might be infected before this outbreak is over. That's nearly 50 times as many cases as the largest Ebola outbreak on record before now.

Before this epidemic, fewer than 3,000 people were known to have contracted the virus in roughly 19 outbreaks dating back to 1976. So when the 20,000 figure was raised, it was almost an unthinkable number.

Now some experts believe 20,000 is optimistic. A modelling study, released Thursday in the online journal Eurosurveillance, suggested that if the pace of new cases continues as it has, there could be between 77,000 and 277,000 additional Ebola cases before the end of 2014.

The authors of that study called that a worse-case scenario and said the scale of containment efforts should prevent case numbers from getting that high. But they said that as of Aug. 26, there was no indication the efforts were turning the tide.

And the aid group Medecins Sans Frontieres said Friday there still isn't. The group, which is also known as Doctors Without Borders, recently called for governments with military field hospitals to deploy those resources to the Ebola zone. The response has been modest at best.

"To this day, the pledges to dispatch field hospitals with isolation capacity remains light years away from what is needed on the ground," the group said Friday.

"If we add up the commitments that we have heard of, we barely reach 100 extra beds when more than a thousand are needed in Liberia and Sierra Leone. In Monrovia, for example, an estimated 1,200 beds in isolated wards are needed, but only 240 are available -- including 160 provided by MSF. These new centres must serve affected people regardless where they are from or their profession."

That last remark was likely a reference to the fact that earlier this week the U.S. Pentagon said it would send a 25-bed field hospital to Liberia -- to treat health-care workers who become infected with Ebola.

MSF said that without places for the sick to go, there is no way to keep the infected from spreading the disease to family or friends who take care of them.

Viruses like Ebola mutate constantly. And each time an animal virus such as Ebola infects a person, it has the chance to develop mutations that make it better adapted to spreading among people.

No one knows what cycling Ebola viruses through so many people would mean in terms of the virus's evolution. But scientists who study Ebola -- one of the deadliest viruses to afflict humankind -- would prefer not to watch the experiment in action.

Osterholm suggested each infection gives the mutating virus "trillions of throws of the genetic dice."

"The current Ebola virus's hyper-evolution is unprecedented; there has been more human-to-human transmission in the past four months than most likely occurred in the last 500 to 1,000 years," he said in his Times commentary.

Ebola currently spreads through exposure to bodily fluids like vomit, blood or feces. Exposure is high risk for those who encounter these fluids, but only those caring for sick patients or preparing the dead for burial do.

"If certain mutations occurred, it would mean that just breathing would put one at risk of contracting Ebola. Infections could spread quickly to every part of the globe, as the H1N1 influenza virus did in 2009, after its birth in Mexico," Osterholm wrote.

In an interview, he noted that the outbreak has crippled the three worst-hit countries: Guinea, Sierra Leone and Liberia. "Ebola virus infection in West Africa has clearly brought these countries to their knees."

International response teams, most led by MSF, have struggled to create and staff sufficient treatment beds for the sick. While it has traditionally staffed the field hospitals during Ebola outbreaks, this time the organization has said it cannot operate as many treatment centres as are needed and it has called on countries and other aid organizations for help.

In Liberia, which has been hit hardest by the outbreak, it was announced a large soccer stadium will be converted into two treatment facilities. Use of the stadium was donated by soccer's international governing body, FIFA.

Osterholm said people might be tempted to slough off the situation by telling themselves that events in West Africa have no bearing on their own lives.

"What are the hallmarks of what's happening? Health-care workers are dying. People are panicked. ... There are shortages of food and water," he said.

"If in this country we suddenly had ongoing respiratory transmission of Ebola virus, health-care workers would die, there'd be panic and fear and we'd suddenly see major shortages of any number of items and goods that we need every day, including most critical medical products."

Osterholm noted that a 2012 study by researchers at the National Microbiology Laboratory in Winnipeg showed that under certain circumstances the Zaire subtype of the virus -- the cause of the current outbreak -- could be spread by the respiratory route between pigs and monkeys.

He said the risk needs to be mitigated by greatly enhanced efforts to stop the spread of the virus, including instituting United Nations control over the response.

"Thus far it has played at best a collaborating role, and with everyone in charge, no one is in charge," he said.

The Security Council should give the UN overriding authority to run the response. Military air and ground support from G-7 countries is needed to ensure supply chains for medical and infection control products, as well as food and water for quarantined areas, he wrote.

Osterholm said humanitarianism isn't the only driving factor demanding a response.

"If we wait for vaccines and new drugs to arrive to end the Ebola epidemic, instead of taking major action now, we risk the disease's reaching from West Africa to our own backyards."

Work is being expedited on experimental vaccines and Ebola drugs, but even if they are shown to work supplies will be limited for months to come.