GENEVA, Switzerland (AFP) – World Health Organization experts began emergency talks Monday on whether Zika virus outbreak suspected of causing a surge in serious birth defects in South America should be declared a global health emergency.

The UN health agency warned last week that the mosquito-borne virus was “spreading explosively” in the Americas, with the region expected to see up to four million cases this year.

The WHO is under pressure to act quickly in the fight against Zika, after admitting it was slow to respond to the recent Ebola outbreak that ravaged parts of west Africa.

Although symptoms of the mosquito-borne virus are relatively mild, it is believed to be linked to a surge in cases of microcephaly, a devastating condition in which a baby is born with an abnormally small head and brain.

While it has yet to be definitively proven that the microcephaly cases are caused in some way by the Zika virus, WHO chief Margaret Chan warned last week that a causal relationship was “strongly suspected”.

Zika is also believed to be linked to a neurological disorder called Guillain-Barre syndrome.

Brazil sounded the alarm in October when a rash of microcephaly cases emerged in the northeast. 

It has since become the country worst affected by microcephaly, with 270 confirmed cases and 3,448 suspected cases, up from 147 in 2014.

As alarm grows over the surge in number of cases, Colombia, Ecuador, El Salvador, Jamaica and Puerto Rico have warned women to delay conceiving until the Zika outbreak is brought under control.

Jitters over Zika have spread far beyond the affected areas to Europe and North America, where dozens of cases have been identified among people returning from holiday or business abroad.

– Resolute action –

In a bid to forge a response to the outbreak, Chan called Monday’s closed-door meeting of the WHO’s emergency committee to determine if Zika should be considered a “public health emergency of international concern”.

The emergency meeting – a global telephone conference grouping senior WHO officials, representatives of affected countries, and international experts –  began shortly after 1200 GMT. No decision is expected before Tuesday at the earliest. 

Such consultations are relatively rare, underlining the scale of concern felt by the organisation.

The UN agency will be looking to take resolute action on Zika after coming in for stinging criticism over its initially sluggish response to the devastating west Africa Ebola outbreak.

Ebola, which has killed more than 11,000 people in west Africa since late 2013, was declared a global health emergency in August 2014 and continues to carry that label. 

As for Zika, there is currently no treatment and the WHO has said it would likely take more than a year to develop a vaccine.

The virus is transmitted by the Aedes aegypti mosquito, which also spreads dengue fever and the chikungunya virus. It produces flu-like symptoms including a low-grade fever, headaches, joint pain and rashes.

WHO has so far refrained from issuing travel warnings related to Zika, stressing that the most effective form of prevention is getting rid of stagnant water where mosquitos easily breed, and using personal protection against mosquito bites such as using repellant and sleeping under mosquito nets.