As the Ebola epidemic threatens to overwhelm response efforts in West Africa, calls for international military assistance are picking up.

The medical charity Doctors Without Borders called on world leaders to send military units with expertise in biohazard containment to combat the worst outbreak of the virus on record.

The European Commission’s humanitarian arm (ECHO) is also calling  for military medical intervention to combat the epidemic, including U.S. Army and Navy Seal protection teams.

But ECHO health adviser Jorge Castilla-Echenique warned of the high financial costs involved in a “M.A.S.H. like operation” in an interview with Thomson Reuters Foundation. U.S. Army mobile surgical hospitals have the capacity to serve as fully functional health facilities, but they do not come cheap, he said.

With many major carriers, including British Airways, suspending flights to the worst-affected countries, military forces might also set up “air bridges” needed to move personnel and materials to West Africa and within countries where travel restrictions and quarantines have affected mobility.

More than 3,000 people have been infected with Ebola across Liberia, Sierra Leone, Guinea, Nigeria and Senegal. The World Health Organization estimated up to 20,000 people could be infected in the next six months.

The death toll from the epidemic in West Africa has surpassed 1,900 people, the WHO’s chief said Wednesday.

Less than a week ago, the death toll stood at 1,552 people. More people have now died in the 2014 Ebola epidemic than in all previous outbreaks combined (1,590, according to WHO).

“To curb the epidemic, it is imperative that states immediately deploy civilian and military assets with expertise in biohazard containment,” Joanne Liu, president of Doctors Without Borders, told United Nations officials in New York on Tuesday. Six months into the outbreak, Liu said, the world is losing the battle to contain it.

“Without this deployment, we will never get the epidemic under control,” she said.

A third American aid worker infected with Ebola in Liberia was identified on Wednesday as Rick Sacra, a doctor with the North Carolina-based missionary group SIM, which runs the ELWA hospital in the Liberian capital of Monrovia, the Associated Press reported.

The Boston-area obstetrician and father of three was delivering babies, not treating Ebola patients. His experience underlines the risk all those working in health care settings in affected countries are taking to treat patients without sufficient supplies of protective gear — and the fact charities with limited resources cannot tackle this epidemic.

“Due to the weak health system in Mano River basin, our best option will be to get outside military help to the response,” said Suafiatu Tunis, a spokeswoman for Community Response Group, a grass-roots initiative to combat Ebola in Sierra Leone and a leader of the Social Mobilization Committee on Ebola that reports to the National Task Force. “Even our health workers no longer want to work in our health centers because of lack of safety for them…so in my opinion having the military come in will help our region immensely.”

Last week, the World Health Organization offered a six-month, $490-million plan to contain the epidemic, but Doctors Without Borders warned it would be impossible for the United Nations and aid organizations to  implement this emergency response plan alone.

Efforts to combat Ebola require massive human resources to trace those infected and those they have come in contact with. Military assets and personnel deployed to the region could assist in meeting emergency needs, including dramatically increasing the number of isolation wards, field hospitals and mobile laboratories and distributing hygiene products on a mass scale.

Management of corpses also needs to be urgently improved, advised Doctors Without Borders, since the handling of highly infectious dead bodies and burial practices is a main route of transmission. With the response stretched to its limits, the organization reports that, in Sierra Leone, infected dead bodies have been left in the street.

Doctors Without Borders said, however, that any military assets or personnel deployed should not be used for quarantine, containment or crowd control measures, since forced quarantine and restrictions on communities have only stoked fear and mistrust of authorities.