The infection, which results in mild fever, conjunctivitis and headache, has also been linked to a rise in the number of babies being born with a foetal deformity known as microcephaly, which results in an underdeveloped brain.
Margaret Chan, WHO’s executive director, said in a speech to the organisation’s executive board today: “The explosive spread of Zika virus to new geographical areas, with little population immunity, is a cause for concern, especially given the possible link between infection during pregnancy and babies born with small heads.
“Although a causal link between Zika infection in pregnancy and microcephaly has not been established, the circumstantial evidence is suggestive and extremely worrisome. An increased occurrence of neurological syndromes, noted in some countries coincident with the arrival of the virus, adds to the concern.”
She said that all newly affected countries had quickly detected the outbreak and promptly informed WHO, and that she had asked the head of WHO in the Americas to brief the board later this week on the organisations response to the outbreak.
Brazil reported the first cases of local transmission of the virus in May 2015. Since then, there have been 3,893 cases of suspected microcephaly in the country, over 30 times more than have been reported in any year since 2010. In November, the Brazilian health ministry confirmed the virus was linked to the foetal abnormality, however why a usually mild infection is causing this is still uncertain.
In a statement yesterday, WHO said that the virus, which has historically occurred in Africa, south-east Asia and the Pacific Islands, has spread so quickly because the population of the Americas have not been previously exposed and therefore have no immunity and because of the presence of Aedes mosquitoes which transmit the virus.
WHO ancicipates the virus will continue to spread and will likely reach all countries of the Americas where Aedes mosquitoes are found, which includes everywhere apart from Chile and Canada, and beyond.
