Zika, which can cause birth defects including a devastating syndrome known as microcephaly
The World Health Organization has ruled out any change in timing or the location of the upcoming Olympic Games in Rio de Janeiro, shunning a call by doctors and scientists to shift the event over the Zika virus.
An open letter addressed to the world health body signed by 150 international doctors, scientists and researchers Friday had called for the August Games to be moved or delayed to help prevent the spread of Zika virus.
Holding the Games in Rio, the second worst affected city in Brazil, would be "irresponsible" and "unethical" and could risk spreading the virus to "poor, as-yet unaffected places" like Africa and South Asia, said the letter.
Zika, which can cause birth defects including a devastating syndrome known as microcephaly in which babies are born with unusually small heads and brains, can be introduced to a new region when a local mosquito picks it up from an infected human.
If it lives long enough, the mosquito then infects people from whom it subsequently takes blood, starting a vicious cycle.
But the WHO said moving the Olympics would not have a major impact on the spread of Zika.
"Based on current assessment, cancelling or changing the location of the 2016 Olympics will not significantly alter the international spread of Zika virus," it said.
Nearly 1,300 babies have been born in Brazil with irreversible brain damage since the mosquito-borne Zika began to spread there last year.
The virus can also cause adult-onset neurological problems such as Guillain-Barre Syndrome, which can cause paralysis and death.
"An unnecessary risk is posed when 500,000 foreign tourists from all countries attend the Games, potentially acquire that strain, and return home to places where it can become endemic," experts from the United States, Britain, Canada, Norway, the Philippines, Japan, Brazil, South Africa, Turkey, and Lebanon, among others, had stated in their letter.
"Should that happen to poor, as-yet unaffected places (e.g., most of South Asia and Africa) the suffering can be great," it added.
The World Health Organization and top US public health officials have called on those traveling to Brazil to take precautions against mosquito bites, and have said pregnant women should avoid areas where Zika is circulating, including Rio.
The Olympics and Paralympics, set for August 5 through September 18, "will take place during Brazil's wintertime when there are fewer active mosquitoes and the risk of being bitten is lower," the organisation said this month.
On Thursday, the top US public health official, Tom Frieden, said "there is no public health reason to cancel or delay the Olympic Games".
But the open letter, signed by doctors and researchers at leading universities around the world, expressed worry that officials are not adequately protecting the public against the danger posed by Zika.
"It is unethical to run the risk, just for Games that could proceed anyway, if postponed and/or moved."
The letter urged the WHO to "conduct a fresh, evidence-based assessment" of the situation in Brazil and its recommendations for travelers.
- 'Conflict of interest' -
Given the big financial investments at stake, the letter questioned whether the UN health agency was able to give a non-biased view of the situation.
It said the world body may not be properly considering the options, which include moving the Games to a place where Zika is not present, postponing them until Zika is under control, or cancelling them.
"We are concerned that WHO is rejecting these alternatives because of a conflict of interest," said the letter.
"Specifically, WHO entered into an official partnership with the International Olympic Committee, in a Memorandum of Understanding that remains secret."
It called on the UN health agency to disclose the memo.
"Not doing so casts doubt on WHO's neutrality," it said.
"WHO must revisit the question of Zika and postponing and/or moving the Games. We recommend that WHO convene an independent group to advise it and the IOC in a transparent, evidence-based process in which science, public health, and the spirit of sport come first," the letter said.
"Given the public health and ethical consequences, not doing so is irresponsible."