The World Health Organization says the mosquito-borne Zika virus is expected to spread to all countries

in North and South America except for Canada and Chile.

The virus has been linked with rising cases of microcephaly, a disorder in which infants

are born with smaller craniums and brains. One-and-a-half million people in Brazil are

thought to have been infected by the virus. The situation is so serious that Brazil, Colombia

and El Salvador have warned women to avoid becoming pregnant for two years.

The WHO says any women planning to travel to affected areas should see a doctor before

travelling and on return.