The dangerous Zika virus is inching closer to India. India’s foreign ministry confirmed that 13 Indian nationals in Singapore had tested positive for the virus. Singapore has seen a sudden outbreak and surge of Zika infections in the past week.

Singapore has confirmed 115 cases of Zika virus infection so far, among which 57 are foreigners of seven nationalities including India and China who live and work in Singapore. The worst affected seem to be foreign workers at construction sites, although whether the 13 Indians are among the group is not known.

"According to our mission in Singapore, 13 Indian nationals have tested positive for Zika," Vikas Swarup, spokesman for the Ministry of External Affairs, told Reuters on Thursday.

Ever since the Zika outbreak in Brazil last year and its spread through and out of South America, public health experts have been anticipating with some trepidation what might happen if the virus comes to India. Epidemics of any kinds are bad news for India with its 1.3 billion people and sketchy healthcare system.

A study from the University of Oxford in April this year found that Asia has the most people living in areas that are suitable for Zika virus at 1.42 billion. A large part of the susceptible population is in India with more than 2 million square kilometers having tropical environment suitable for the transmission of the virus.

Going viral

The Zika scare began in March 2015 in Brazil with reports of illness characterised by skin rashes coming in from the country's northeastern states. By July, Brazil’s health authorities reported neurological disorders in newborns associated with infection. By October, Brazil started reporting a sudden increase in microcephaly, a condition in which newborns had abnormally small heads.

Zika infections were reported across central and South America – from Mexico to Paraguay and Belize to Bolivia – between November 2015 and January 2016. By this time Brazil had already announced a public health emergency. In February, the World Health Organization declared a public health emergency of international concern. Since then the Zika virus has made its way into the United States, to several Pacific Islands and now to Asia with Singapore and Malaysia reporting infections.

Cause and effect

Zika is mainly transmitted by the bite of an Aedes mosquito, 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 to a week.

Links are also being made between Zika infections and 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, as the name suggests, 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.

Viral history

The discovery of Zika dates back to 1947 when scientists studying yellow fever in Uganda’s Zika forest found the virus in a rhesus monkey. Human cases of Zika infection were recorded in Uganda, Tanzania and Nigeria a few years later. Between the 1960s and 1980s Zika was detected in mosquitoes and monkeys across equatorial Africa and also in Asia, including India, Indonesia, Malaysia and Pakistan.

In 2012, scientists figured out that there were two strains of the Zika virus, one of African and one of Asian lineage. The 2015-2016 Zika outbreak seems to have been caused by the Asian Zika virus that originated in south east Asia but made its way to South America having possible undergone mutations and turned virulent on the way. The disease causing virus is now well on its way back.