WASHINGTON, Sept. 2 (Xinhua) -- The head of the U.S. Centers for Disease Control and Prevention (CDC) warned Tuesday that the window of opportunity for curbing the Ebola outbreak in West Africa is closing rapidly and called for "an overwhelming response " to bring the unprecedented epidemic under control.
CDC director Tom Frieden, who just returned from a trip to countries in West Africa affected by Ebola, described a daunting situation, saying the number of Ebola cases there "continues to increase and is now increasing rapidly."
"I'm afraid that over the next few weeks those numbers are likely to increase further and significantly," Frieden said. " There is a window of opportunity to tamp this down, but that window is closing. We need action now."
He said more resources, technical experts and a global, coordinated unified approach are needed to deal with the outbreak, the worst in the nearly four-decade history of this disease.
"The number of cases is increasing so quickly that for every day's delay it becomes that much harder to stop it," he continued. "This is not just a problem for West Africa, not just a problem for Africa, it's a problem for the world, and the world needs to respond."
In the meantime, the U.S. government said Tuesday it will support accelerating the development of an experimental drug known as ZMapp through a contract worth up to 42.3 million U.S. dollars with the San Diego-based Mapp Biopharmaceutical.
ZMapp probably saved the lives of two U.S. aid workers who contracted Ebola in Liberia while treating patients, but the medication has never been formally tested in humans.
"While ZMapp has received a lot of attention, it is one of several treatments under development for Ebola, and we still have very limited data on its safety and efficacy," said Nicole Lurie, assistant secretary for preparedness and response.
ZMapp has been shown to reduce mortality in mice and nonhuman primates exposed to deadly Ebola viruses, but as an experimental drug, it is currently available only in very limited quantities.
The latest official number of Ebola cases in Guinea, Liberia, Nigeria, and Sierra Leone stands at 3,069, with more than 1,552 deaths, making this the largest Ebola outbreak ever recorded, according to the World Health Organization.