The race to control the expanding Ebola epidemic in West Africa looks increasingly dire. Official projections of how fast the virus will spread have soared while pledges of help from advanced nations and global organizations have failed to keep pace.

On Sept. 22, the World Health Organization published estimates indicating that the epidemic could infect more than 20,000 people in the three hardest hit countries — Guinea, Liberia and Sierra Leone — by early November, months before earlier estimates. Unless new measures can turn the tide, the number of cases and deaths could increase by thousands per week for months to come. It is possible that the virus will become permanently lodged in the West African population, posing a continuing threat of dispersal to the rest of Africa and other parts of the world.

On Sept 23, the Centers for Disease Control and Prevention in Atlanta issued in a worst-case projection, based on computer models, showing that Sierra Leone and Liberia may have 1.4 million cases by Jan. 20 if the disease keeps spreading without effective containment. A best-case scenario showed that the epidemic could be brought to an end if 70 percent of the patients were treated in settings like isolation wards that reduce the risk of disease transmission and if burials were performed safely. Currently, only about 18 percent of the patients in Liberia and 40 percent in Sierra Leone are in such settings.

There is an urgent need to provide more health workers to track down every patient’s contacts for testing, and more workers to bury victims safely. Home health kits are needed to protect people from infection when family members become sick, and local leaders must persuade an often hostile public to take precautions. Health care systems that have disintegrated must be rebuilt so that people don’t die from other afflictions while treatment facilities are clogged with Ebola patients. It is a task of mind-boggling complexity, requiring international assistance on a massive scale.