The United Kingdom has classified India as having a “moderate” risk of Zika virus transmission. It has advised pregnant women to avoid travelling to India. “Details of specific affected areas within this country are not available,” the National Travel Health Network and Centre said on its website.

This comes after Gujarat’s government was criticised for not revealing that three of its residents had tested positive for the virus. A 64-year-old man and two pregnant women, aged 34 and 22, tested positive for it earlier this year. The news was released by the World Health Organisation on May 27. Though the state government defended its decision to not reveal the three cases, it has raised many ethical questions about how the matter was handled.

The Zika virus had held Brazil hostage between 2015 and 2016. The World Health Organisation lifted the international emergency status given to the transmission of the virus on November 18, 2016.

What is the Zika virus?

The Zika virus is mainly transmitted by Aedes mosquitoes, including Aedes aegypti that carries dengue. The virus can also be sexually transmitted.

Most people infected with Zika will show no symptoms or will have only mild symptoms of fever, rash, joint pain, conjunctivitis and, possibly, muscle pain and headaches that may last for several days to a week.

Zika infections are linked to incidences of Guillain-Barré syndrome, a nervous system disorder caused by a person’s own immune system attacking nerve cells, causing muscle weakness, and sometimes, paralysis.

The biggest danger from Zika, however, is when pregnant women get infected. The Zika virus can pass on from a woman to the foetus, which is most vulnerable to its effects. Zika can cause many developmental disorders in a foetus, the most commonly reported disorder now being microcephaly. Microcephaly is a condition of an abnormally small head caused by a much smaller number of neurons and brain material being produced during a foetus’ development.