The mosquito-borne Zika virus, which is suspected of causing brain damage to babies in Brazil, is expected to spread to all countries in the Americas except for Canada and Chile, Reuters cited the World Health Organization as saying on Monday. The WHO said women planning to travel to areas where Zika is circulating should consult a healthcare provider before travelling and on return. Zika can be transmitted though blood, and has also been isolated in human semen, but more evidence is needed to confirm if it can be sexually transmitted, WHO said.