Peter Piot, an award-winning microbiologist, told Al Jazeera that "we wasted too much precious time."
"It took three months for the WHO to find out there was an Ebola outbreak. That I understand. Guinea had a poor laboratory infrastructure," said Piot in an interview due to be aired on Saturday.
"I have much more of a problem with the fact that it took five months for WHO, for the international health regulations committee, for that's what it is, to declare this a state of emergency.
"It took a thousand dead Africans and two Americans who were repatriated to the US because they were infected. There's no excuse for that. ... It took too long."
Tarik Jasarevic, a spokesman for WHO, told Al Jazeera by email that "declaring a public health emergency of international concern is not a measure of WHO's operational response."
Jasarevic said that WHO measures its operational response on a scale from one to three.
"As soon as WHO received notification from Guinea in late March that the first cases of Ebola virus disease had been identified, we immediately increased our operational response to Level 2," said Jasarevic. "And we mobilized experts to Guinea, then to Liberia and Sierra Leone through our Global Outbreak Alert and Response Network."
'Ebola hysteria'
Having waited too long to act, Piot said the international community has overreacted in unhelpful ways.
"An epidemic of mass hysteria that we saw particularly in North America ... was really out of proportion with the issue."
He gave an example of the governors of New York and New Jersey who made it mandatory for healthcare workers from West Africa to be put under quarantine.
"It's not cost-effective and also it's a major deterrent and disincentive for supporting the countries in West Africa," said Piot.
He said any potential solutions needed to address both the lack of robust healthcare systems and the local population's cultural habits and belief systems.
©2014 Al Jazeera (Doha, Qatar). Distributed by Tribune Content Agency, LLC.
