Explainer: What is the Zika virus?

Scientists have warned people in tropical environments about the alarming rise in people becoming infected with the Zika virus.

With 1.5 million people in Brazil thought to have been infected and women warned to delay pregnancy, we take a closer look at the disease.

• Zika was first discovered in Africa in the 1940s taking its name from the Zika forest in Ghana where it was first discovered.

• There are currently confirmed cases in 18 states in Latin America and the Caribbean.

• The disease is not contagious and is spread by the same mosquito that carries dengue fever and yellow fever.

• Typical symptoms are similar to the flu, including fever, joint pain, rash, conjunctivitis, headache and muscle pain.

• About 1 in 5 people infected with the virus develop Zika and become ill according to the Centers for Disease Control and Prevention.

• The virus has been linked to babies being born with microcephaly, abnormally small heads, but this is unconfirmed.

• Women in countries with an outbreak have been warned to avoid becoming pregnant.

• There is currently no vaccine or treatment for the virus.

Public Health England have issued assurances that Zika does not "naturally occur" in the UK, but pregnant women travelling to affected regions should take precautions.