The World Health Organisation has declared the mosquito-borne Zika virus to be an international public health emergency as the disease linked to thousands of suspected cases of birth defects in Brazil spreads rapidly.
WHO director-general Margaret Chan said on Monday an international coordinated response was needed to improve detection and speed work on a vaccine and better diagnostics, although curbs on travel or trade were not necessary.
The emergency designation was recommended by a committee of independent experts to the UN agency after criticism of a hesitant response so far.
The move should help fast-track international action and research priorities.
“Members of the committee agreed that the situation meets the conditions for a public health emergency of international concern. I have accepted this advice,” Ms Chan said.
The WHO said last week the Zika virus was “spreading explosively” and could infect as many as 4 million people in the Americas. Brazil is due to host the Olympic Games in Rio de Janeiro in August.
The WHO was lambasted for reacting too slowly to the Ebola epidemic in West Africa, which killed more than 10,000 people, and has promised to do better in future global health crises.
US Centres for Disease Control and Prevention head Thomas Frieden said the declaration “calls the world to action” on Zika.
“The WHO faced heavy criticism for waiting too long to declare the Ebola outbreak a public health emergency and they should be congratulated for being far more proactive this time,” Jeremy Farrar, director of the Wellcome Trust medical charity, said.
Link to underdeveloped brains
Brazil has reported nearly 4,000 suspected cases of microcephaly, in which infants are born with smaller-than-usual brains.
The health ministry has linked the condition to Zika, although the connection is not yet definitive.
Ms Chan said the causal link was “strongly suspected but not yet scientifically proven”.
Brazilian Health Minister Marcelo Castro said the epidemic was worse than believed because in 80 per cent of the cases the infected people had no symptoms.
As the virus spreads from Brazil, other countries in the Americas are also likely to see cases of babies with Zika-linked birth defects, experts believe.
The Pan American Health Organisation said Zika had now spread to 24 nations and territories in the Americas.
Colombia has so far reported more than 20,000 cases of Zika, including 2,100 in pregnant women.
Pregnant women to reconsider travel
The Zika virus has raised questions worldwide about whether pregnant women should avoid infected countries.
Ms Chan said delaying travel was something pregnant women “can consider”, adding that if they needed to travel they should take personal protective measures by covering up and using mosquito repellent.
The clinical symptoms of Zika are usually mild and often similar to dengue, a fever which is transmitted by the same aedes aegypti mosquito, leading to fears that Zika will spread into all parts of the world where dengue is commonplace.
The Zika emergency comes at a particularly bad time for Brazilian President Dilma Rousseff’s unpopular government, adding a new burden to a public health system hit by budget cuts in the midst of a severe recession.
It has also cast a shadow on Brazil’s hosting of the Olympic Games in Rio de Janeiro in August.
Mr Rousseff’s chief of staff said pregnant women should not travel to the Games.
“The risk, which I would say is serious, is for pregnant women,” cabinet chief Jaques Wagner said.
“It is clearly not advisable for you [to travel to Rio de Janeiro for the Games in August] because you don’t want to take that risk.”
The Rousseff Government said there was no chance the Games would be called off due to the health scare.
“We have to explain to those coming to Brazil, the athletes, that there is zero risk if you are not a pregnant woman,” Ms Rousseff’s chief of staff, Jaques Wagner, told reporters.
The Brazilian Government suspects the virus was brought to the country during the 2014 soccer World Cup by a visitor from Africa or Oceania where Zika is endemic.
An estimated 1.5 million Brazilians have caught Zika, a virus first detected in Africa in the 1947.
Australia likely to join fight against Zika, doctor predicts
Doctor Grant Hill-Cawthorne, a Sydney University communicable disease epidemiology lecturer, said it was reassuring to see WHO’s response to the Zika virus, after criticisms over the response to the West African Ebola outbreak.
“They didn’t declare this public health emergency early enough for Ebola, so it sort of tied people’s hands when they were trying to get international aid,” he said.
“This has been recognised as likely to spread … from modelling figures, up to 4 million people are at risk this year from this virus, so this would be a good move.”
Dr Hill-Cawthorne said it was likely the Australian Government would be asked to contribute to a global effort led by the WHO against Zika.
“A lot of the efforts will now be on countries like Australia to help South American countries to get on top of this,” he said.
“I think it would be very prudent, particularly considering we are likely to see cases in northern Queensland of this, it would be in Australia’s best interest to try and help on the ground where the concentration of cases are greatest.”
Foreign Affairs Minister Julie Bishop has been contacted for comment.