"Health workers have died [fighting Ebola], including medical doctors at … JFK and to have them come to work without food on their table, we think that is pathetic," George Williams, secretary general of the Health Workers Association of Liberia, told Reuters.

The action by scores of employees at the John F. Kennedy Medical Center in Liberia's capital Monrovia followed a similar protest over pay and conditions at Connaught Hospital in Sierra Leone on Monday. Both hospitals have treated Ebola patients.

Health care workers at Liberia's main hospital went on strike on Tuesday over unpaid wages, complicating the fight against an Ebola outbreak that the U.S. disease prevention chief has characterized as "spiraling out of control."

"Upon onset of the symptoms, the doctor immediately isolated himself and has since been transferred to the ELWA Ebola isolation unit. The doctor is doing well and is in good spirits," SIM USA said in a statement.

In a separate development, the Christian charity SIM USA said on Tuesday that one of its missionary doctors in Liberia who was treating obstetrics patients at its hospital in Monrovia had tested positive for the Ebola virus.

More than 120 health workers have so far died from Ebola amid shortages of equipment and trained staff in the region. That is nearly a tenth of the total number killed by the disease, mostly in Liberia, Sierra Leone and Guinea .

The World Health Organization and other international bodies are scrambling to support the fragile health care systems in some of the world's poorest countries, but so far additional staff and resources have been slow to arrive on the ground.

The recent outbreak of Ebola in mainly West Africa has claimed 1,552 lives and may have infected as many as 20,000 people, health officials said.

Williams said health care workers at JFK, Liberia's largest referral hospital, had not been paid for two months.

'Out of control'

Tom Frieden, director for the U.S. Centers for Disease Control and Prevention, said on Tuesday that Ebola was accelerating very fast and urged more global support to combat the outbreak.

"It's spiraling out of control. The situation is bad and it looks like it's going to get worse quickly. There is still a window of opportunity to tamp it down but that window is closing, and we need to act now," he told NBC News in an interview following a trip to Africa.

"This is different than every other Ebola situation we've ever had. It's spreading widely, throughout entire countries, through multiple countries, in cities and very fast," he said, speaking from CDC headquarters in Atlanta.

Frieden called on health officials to immediately seek to reverse the outbreak by sending in more resources and specialized workers, adding that the U.S. government now has 70 people in the region.

The countries affected want to fight the outbreak but face limited resources, he added. "There is a willingness there to confront it, but they need the world to support them."

Putting further pressure on the ability of the region's governments to spend money on health care, the epidemic has also put harvests at risk and sent food prices soaring in West Africa, the U.N. Food and Agriculture Organization (FAO) said.

Restrictions on people's movements and the establishment of quarantine zones to contain the spread of the virus has led to panic buying, food shortages and price hikes in countries ill-prepared to absorb the shock.

"Even prior to the Ebola outbreak, households in some of the most affected areas were spending up to 80 percent of their incomes on food," said Vincent Martin, head of an FAO unit in Dakar that is coordinating the agency's response.

"Now these latest price spikes are effectively putting food completely out of their reach," Martin said in a statement.

Al Jazeera and wire services