Zika outbreak likely to reach across Americas: WHO

Zika has not yet been reported in the continental UnitedStates, although a woman who fell ill with Zika in Brazil latergave birth to a brain-damaged baby in Hawaii.

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Brazil has reported 3,893 suspected cases of microcephaly,the WHO said last Friday, over 30 times more than had beenreported in any year since 2010.

The disease's rapid spread, to 21 countries and territoriesof the region since May 2015, is due to a lack of immunity amongthe population and the prevalence of the Aedes aegypti mosquitothat carries the virus, the WHO said in a statement.

Evidence about other transmission routes is limited.

"Zika has been isolated in human semen, and one case ofpossible person-to-person sexual transmission has beendescribed. However, more evidence is needed to confirm whethersexual contact is a means of Zika transmission," it said.

It advised pregnant women planning to travel to areas whereZika is circulating to consult a healthcare provider beforetravelling and on return.

WHO Director-General Margaret Chan told the WHO executiveboard that she had asked Carissa Etienne, head of the WHO in theAmericas, to brief the board later this week on the WHO'sresponse to the outbreak.

"An increased occurrence of neurological symptoms, noted insome countries coincident with arrival of the virus, adds to theconcern."