One expert says the World Health Organization (WHO) should accept responsibility for the ongoing spread of the Ebola virus in West Africa.

The current Ebola outbreak has infected more than 22,000 people and killed over 9,000 of them.

New York University Professor Karen Grepin has written an article for the British Medical Journal arguing that the WHO took too long to declare the outbreak a public health emergency.

“It took a really long time for international leaders like the WHO and others to actually call on international donors to give resources,” Dr Grepin said in an interview with the ABC.

“And then once donors made pledges it takes a couple of months sometimes for some of those resources to actually reach the country.

“There were significant delays on a number of the resources and it could be that by the end of 2014 only about $1 billion [of $3 billion raised] had actually reached the affected countries.

“Had resources been made available in a more rapid fashion then we could have seen a much bigger response and likely that we would have seen the turning of the epidemic much sooner than we currently are.

“It's possible even that it wouldn't have spread much beyond the original cases if we had actually rotated the money in time and so I do believe that the delay in funding has led to more cases of Ebola than would have happened otherwise,” Dr Grepin said.

She was asked if it should be considered a failure of the WHO.

“I definitely think so,” Dr Grepin replied.

“I think already everybody is asking why and how we could have let this go on for so long.

“Every epidemic of Ebola in the past has been addressed relatively rapidly and hasn't spread and we know how to do these things.

“It's not rocket science, it's not inventing the wheel... it's really about getting resources into this country and it took a really long time for that to happen.

“The WHO is ultimately responsible for this and so I think... they can be blamed for this failure,” she said.