A banner on Zika virus outbreak is pictured on the opening of the World Health Assembly.
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WHO: We constantly assess the risk of Zika virus

The World Health Organization has rejected a call by health experts for the Brazil Olympics to be postponed, in order to halt the spread of the Zika virus.

Specialists have written an open letter to the WHO, warning that the Games may accelerate the transmission of Zika to tropical countries.

Dr Bruce Aylward from the World Health Organization says it is already taking steps to tackle the outbreak, but better communication is needed with people concerned about the spread.

Go to next video: What is the Zika virus?