The disease has been linked with a birth defect known as microcephaly, which sees children born with abnormally small brains, as well as a neurological syndrome that can cause paralysis.
An Aedes Aegypti mosquito is photographed on human skin in a lab of the International Training and Medical Research Training Center (CIDEIM) on January 25, 2016, in Cali, Colombia.
Margaret Chan, the director-general of the WHO, said board members would meet on Monday 1 February to establish if the Zika virus should be declared an international emergency.
And an official at the organization’s office for the Americas, where the disease has spread to 23 countries in a matter of months, said we can "expect three to four million cases".
HOW THE DISEASE SPREAD
Though it is possible the Zika virus originates in South East Asia, it was first documented in Uganda in 1947 (marked by (1) in the map above) in the antibodies of local people, meaning they had been exposed to it in the past.
It spread throughout Africa, with the first live case recorded in a human patient in Nigeria a decade later around 1960 (2). The outbreak only threw up around a dozen confirmed cases.
In 1966, the first case was confirmed in South East Asia, and in the late 1970s it was documented in Pakistan, India, Malaysia and Indonesia (3).
The first official epidemic was on the isolated island of Yap, Micronesia, in 2007 (4). It affected almost 200 members of the island's small population, making it a relatively major crisis.
It hit French Polynesia in 2013, with a huge outbreak of 35,000 cases (5). Some led to instances of Guillain-Barre syndrome and paralysis, while recent retrospective research suggests there was also a corresponding spike in microcephaly.
In 2014, around the time of the football World Cup, Zika arrived in northern Brazil (6). Some suggest it could have been brought over during the World Canoeing Championships in Rio around the same time, an event which involved a large number of Pacific Islanders.
It spread slowly through Brazil for around a year, before the WHO reported the first outbreak outside the country - Colombia - on 21 October 2015.
Other countries then followed quickly, with transmission reported in Suriname, El Salvador, and Guatemala by the end of November.
In early December, the disease spread to Mexico for the first time, raising concerns in the US, as well as to Paraguay, Venezuela and Panama.
By the start of January, Honduras, Puerto Rico, French Guyana and Martinique in the Caribbean had cases.
And in the past week or so, cases have been confirmed in Guyana, Barbados, Ecuador, Bolivia, Haiti and the Dominican Republic.
A handful of isolated cases have been reported locally in the US, the UK, Denmark and now Germany (7) - though experts stress these are all travel-related and full outbreaks in these countries are unlikely.
And meanwhile, there have been several thousand cases of Zika reported in Cape Verde of West Africa since September. It is not known for certain whether these were imported there from mainland Africa or from fellow Portuguese-speaking Brazil. If the latter is the case, the disease has circumnavigated the globe - and could legitimately be described as a pandemic; timesofindia reported.
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