The Ebola outbreak in West Africa illustrates how infectious diseases can easily cross borders and needs to be a global priority, U.S. President Barack Obama says.

Obama was speaking Friday at Global Health Security Agenda Summit held at the White House.

Representatives from more than 40 countries are attending the summit, which aims to prevent avoidable catastrophes and epidemics, detect threats early with real-time disease tracking and diagnostic testing, and respond rapidly and effectively.

The World Health Organization said Friday that the number of deaths linked to the Ebola outbreak in West Africa is now 3,091. More than 6,500 people have been infected, chiefly in Sierra Leone, Liberia and Guinea.

"We have to change our mindsets and start thinking about biological threats as the security threats that they are, in addition to being humanitarian threats and economic threats. We have to bring the same level of commitment and focus as we do when meeting around more traditional security issues," Obama said.

Obama issued a challenge to inventors to design better protective gear for health-care workers. The current masks, respirators, gloves and gowns that health-care workers must wear when treating patients infected with Ebola are hot and cumbersome and can introduce the infection if not donned and removed carefully.

Obama called it unacceptable that so many people are dying from Ebola infections given the medical talent and technology that are available. But West Africa’s outbreak also illustrates how planning and preparation, such as having enough trained specialists ready to deploy, can make a difference.

"Starting in West Africa, we've got to make sure we never see a tragedy on this scale again and we have to make sure we aren't caught flat-footed."

Ebola infections are treated with supportive care such as providing intravenous fluids and maintaining oxygen levels and blood pressure.

While the short-term focus is on ensuring infections don’t become outbreaks, Obama said that in the longer term, strengthening the health of individuals, such as by immunizing children, and ensuring they are well fed and have opportunities to get out of extreme poverty, are also part of the agenda.

Experimental vaccine soon available

Earlier on Friday, the World Health Organization announced that spread of the disease in Guinea appears to have stabilized. But in Sierra Leone, three more districts are under indefinite quarantine to try to stop the spread of the virus.

An official with UN’s health agency also said that thousands of experimental Ebola vaccines should be available in the coming months, and could eventually be given to health-care workers and others in close contact with those made sick by the virus.

No vaccine has been proven safe or effective in humans, said Marie-Paule Kieny, assistant director general at WHO. NewLink Genetics Corp. Kieny estimated about 1,500 effective doses could be available.

By January, another 10,000 doses of another vaccine, developed by the U.S. National Institutes of Health and GlaxoSmithKline, should also be available for use on a limited basis.

Data will be collected from clinical trials when the experimental vaccines are being given to healthy volunteers who will be monitored for any adverse side-effects and to see if the shots effectively lead to an immune response.

WHO has approved the use of blood transfusion and infusion of human serum from Ebola survivors, but Kieny said the donated blood must be screened for infections including HIV and hepatitis.

Elsewhere Friday, the International Monetary Fund approved $130 million US to Guinea, Liberia and Sierra Leone for their fight against Ebola.

With files from Associated Press and Reuters