Workers line up to disinfect their protective equipment during the Ebola outbreak response in Mongbwalu, Ituri province.

By Lauren Kent & Jennifer Hansler, CNN

As a deadly Ebola outbreak tears through northeast Democratic Republic of the Congo, many first responders are turning a critical eye on events that preceded the crisis - layoffs of health workers funded by the United States, shortages of critical medical supplies and a steep reduction in American support for global aid programmes.

The World Health Organization says more than a hundred deaths are thought to be linked to this outbreak, with nearly 600 suspected cases so far, and it's warning that "we know the scale of the epidemic in DRC is much larger".

It also said this strain of the virus - for which there is no specific vaccine or treatment - could have been circulating for months, before it was detected.