WHO declares global emergency as Zika virus spreads

The World Health Organisation (WHO) on Monday declared an international emergency over the explosive spread of the mosquito-borne Zika virus, which is linked to birth defects in the Americas, saying it is an ''extraordinary event.''

The decision was taken after an emergency meeting of of independent experts in Geneva to assess the severity of the health threat associated with the spread of Zika virus disease in Latin America and the Caribbean, considering the suspicious link between Zika's arrival in Brazil last year and a surge in the number of babies born with abnormally small heads.

''After a review of the evidence, the committee advised that the clusters of microcephaly and other neurological complications constitute an extraordinary event and public health threat to other parts of the world,'' WHO director general Margaret Chan said.

WHO experts who considered patterns of recent spread and the broad geographical distribution of mosquito species that can transmit the virus, estimate there could be up to 4 million cases of Zika in the Americas in the next year.

The UN body, however, did not recommend any restriction on travel or trade.

Experts agreed that a causal relationship between Zika infection during pregnancy and microcephaly is strongly suspected, though not yet scientifically proven. All agreed on the urgent need to coordinate international efforts to investigate and understand this relationship better.

''The lack of vaccines and rapid and reliable diagnostic tests, and the absence of population immunity in newly affected countries were cited as further causes for concern,'' it said.

''It is important to understand, there are several measures pregnant women can take,'' Chan said. ''If you can delay travel and it does not affect your other family commitments, it is something they can consider.

''If they need to travel, they can get advice from their physician and take personal protective measures, like wearing long sleeves and shirts and pants and use mosquito repellent.''

WHO called for coordinated international response to improve surveillance, the detection of infections, congenital malformations, and neurological complications, to intensify the control of mosquito populations, and to expedite the development of diagnostic tests and vaccines to protect people at risk, especially during pregnancy.

WHO had in 2014 declared such a public health emergency in the wake of the devastating Ebola outbreak in West Africa, which killed more than 11,000 people. A similar declaration was made for polio the year before.

WHO, which was widely criticised for its slow response to the 2014 Ebola crisis in West Africa, has been eager to show its responsiveness this time. WHO didn't declare an emergency until August, when nearly 1,000 people had died of Ebola.

WHO officials say it could be six to nine months before science proves or disproves any connection between Zika and the spike in the number of babies born in Brazil with abnormally small heads.

WHO experts say up to 4 million cases of Zika could turn up in the Americas within the next year.

Zika was first identified in 1947 in a Ugandan forest but until last year, it wasn't believed to cause any serious effects; about 80 per cent of infected people never experience symptoms. The virus has also been linked to Guillain-Barre syndrome, which causes muscle weakness and nerve problems.

WHO spokesman Christian Lindmeier has credited authorities in Brazil for being ''extremely transparent'' since the Zika outbreak turned up there in May.

Brazilian officials shared lab samples with foreign experts and brought in scientists from abroad, he said.

''What we know so far is that the only microcephaly cases we see currently are from Brazil,'' Lindmeier said, noting that abnormally small heads in newborns can have many causes - such as the effects of herbicides, alcohol use, or drugs and toxins. ''This is exactly what is the concerning question: why do we see this in Brazil?''

(Also see: India to issue Zika guidelines by Thursday)