Zika outbreak: What you need to know

The World Health Organization has declared the Zika virus a global public health emergency.

The infection has been linked to thousands of babies being born with underdeveloped brains.

Some areas have declared a state of emergency, doctors have described it as "a pandemic in progress" and some are even advising women in affected countries to delay getting pregnant.

But there is much we do not know.

Zika virus has spread to more than 20 countries in the Americas.

The unprecedented and explosive outbreak of the mosquito-borne disease is causing fear in the affected regions.

While the effects are generally mild, the greatest concern is about a strongly suspected link with brain defects in babies.

There have been no travel bans, but what advice is there for people visiting the regions?

Which countries are affected?

The Pan American Health Organization is publishing updates on the affected countries.
But the virus is expected to spread throughout North, Central and South America, except Canada and Chile, and people should check for the latest advice before travelling.

Should I go?

Only pregnant women have been advised to reconsider their plans to visit countries affected by Zika.

It is thought that within the female body the virus can travel across the placenta and affect the health of an unborn baby.

There has been a surge in microcephaly - in which the baby's brain does not develop properly - in Brazil.