Samuel Tarplah, 48, a nurse running the center, said Saturday evening that the protesters wanted to shut it down. “They told us that we don’t want an Ebola holding center in our community.” He said the intruders stole mattresses, personal protective equipment, even buckets of chlorine that had just been delivered. “They took everything.”

Fear is complicating the huge increase in aid that is needed: food for people in areas that have been cordoned off; laboratory supplies to test for the disease; gloves, face masks and gowns to protect health workers; body bags for the dead; bedsheets to replace those that must be burned. Airlines have canceled flights that could have carried in such supplies, despite assurances from the W.H.O. that properly screened passengers pose little risk. Positions on aid teams remain unfilled.

Hundreds of workers for Doctors Without Borders have fought the outbreak since March. The group’s president, Dr. Joanne Liu, said there was an acute need for materials as well as for more human resources — and not just experts and bureaucrats, but also the kind of person who is ready to “roll up his sleeves.”

“What we have to keep in mind is we are facing today the most devastating and biggest Ebola epidemic of the modern times,” Dr. Liu said. “There is fear, there is a front line, the epidemic is advancing, and there is a collapse of infrastructure.”

A more muscular effort to fight the outbreak began lumbering to life over the past week.

The newly appointed United Nations coordinator for Ebola, Dr. David Nabarro, wrote in an email that he had his “head right down working through some extremely challenging stuff under tight time pressure.”

“All of us are going to have to perform in an outstanding way over some months,” Dr. Nabarro added in a phone interview. “For many, the image is fearful to a degree that it makes it very hard indeed for them to do anything other than think about their safety and the safety of those they love.”