One of the authors of a letter calling for the Rio Games to be postponed over the Zika virus has said it risks becoming the "Olympics of brain damage".
Professor Amir Attaran is one of 152 health experts who have have signed the letter calling for the World Health Organisation (WHO) and International Olympic Committee (IOC) to halt the event or move it elsewhere.
"If you have the Olympics go ahead, adn they bring in a half-million people as expected from all parts of the world.
"Some of them will get infected, certainly, and when they get home they will take the virus with them."
But the WHO has rejected the call, saying suspending or moving it would "not significantly alter" the spread of the virus.
The letter says Zika has more serious medical consequences than first thought and claims the health emergency contains "many uncertainties".
He said: "It is ignorant and arrogant for the WHO to march hand-in-hand with the IOC.
"How can it be ethical to increase the risk of spreading the virus? Just because a fire has begun doesn't mean you need to pour gasoline on it."
But a WHO statement said staging the Games would not have a major impact on the spread of the virus.
It said: "Based on current assessment, cancelling or changing the location of the 2016 Olympics will not significantly alter the international spread of Zika virus.
"Brazil is one of almost 60 countries and territories which to-date report continuing transmission of Zika by mosquitoes People continue to travel between these countries and territories for a variety of reasons.
"The best way to reduce risk of disease is to follow public health travel advice."
Zika has been linked to serious birth defects including microcephaly - where babies are born with abnormally small heads and underdeveloped brains.
It has also been linked to Guillain-Barre syndrome and Acute Disseminated Encephalomyelitis which affect the nervous system.
Nearly 1,300 babies have been born in Brazil with microcephaly since the mosquito-borne Zika began circulating there last year.
The majority of those infected with the virus have no symptoms, but it can cause a mild illness with symptoms including rashes, fever and headaches.
Pregnant women have already been advised not to travel to Rio, but the WHO has said the risk of Zika will lessen in August because it is winter in Brazil. The Rio games are set to begin on 5 August.
