Two babies born with very small heads and brains in Thailand confirmed as south-east Asia’s first cases of the birth defect caused by Zika virus infection put the spotlight on the virus that can potentially harm and even kill unborn babies.
Thailand is one of the most popular destinations for Indians, with the kingdom nation clocking 1,506,000 million tourists from India in 2015, which is a 15% increase in tourist arrivals over the previous year. Thailand has 349 confirmed Zika cases since January, including 33 in pregnant women.
Singapore is the worst hit in Asia, with 393 Zika cases, including 16 pregnant women. Thirteen of those infected in Singapore were Indians, who recovered without associated complications.
Many thousand Indians transit through Thailand and Singapore annually for onward journey to countries like Australia, US and other South East Asian countries.
Apart from Thailand, Indonesia; Malaysia, Philippines and Vietnam are the other countries with confirmed local transmission in Asia.
In February, the world Health Organisation (WHO) declared Zika a public health emergency of global concern after establishing its link with microcephaly in babies and Guillain-Barre syndrome, which can lead to nervous system problems, weakness and partial paralysis.
Updated graphic factfile on the Zika virus worldwide. – AFP / AFP / JOHN SAEKI (AFP)
All pregnant women with or without fever must be screened for Zika virus if they live in or have travelled to countries with localised infection, says the WHO.
There is no cure or vaccine for the virus, which has infected more than 1.5 million people in more than 70 countries since last year, says the WHO, with Brazil the hardest hit.
India under attack
Zika virus disease is spread by a virus transmitted primarily by Aedes mosquitoes, which cause regular dengue and chikungunya outbreaks in India. Though mosquitoes are the main source of spread, Zika virus can also spread through blood transfusions and sexual contact, though the risk is very low.
In most people, the virus causes mild symptoms of fever, rash, conjunctivitis, fatigue and joint pain for two days to a week in most people, but the health risk to unborn children is mindboggling.
New studies show risks to the unborn baby go beyond microcephaly. Up to 6% of Zika-virus-infected pregnant women will miscarry or have stillborn deliveries, reports a comment on the Zika threat to global health in The Lancet. Surviving infants have as much as a 13% chance of Zika-virus-related microcephaly and associated mental, vision and hearing impairments.
Zika virus infection can cause severe joint damage and genitourinary, heart and digestive complications among affected babies, reported a study in The New England Journal of Medicine. Many could be impaired in less obvious ways, with disabilities appearing later in a child’s development.
With 26 million babies born in India every year and 80% of people infected not developing symptoms, the risk is great for lakhs of pregnant women and their unborn babies.
While Zika has been present in South Asia – Bangladesh and Maldives have had confirmed local transmission before 2015 — for years, there has been an uptick in the number of confirmed cases in the region in recent months, mostly because of heightened surveillance for potential cases and improved detection.
Aedes aegypti mosquito, that spreads Zika, also causes seasonal outbreaks of dengue, chikungunya and yellow fever. (AP)
India is a potential hotspot for a Zika outbreak, concluded scientists last month based on an analysis of travel, climate and mosquito patterns in Asia and Africa to identify the highly vulnerable countries such as India, China, Pakistan and Bangladesh, where the Aedes aegypti mosquito that spreads Zika also causes seasonal outbreaks of dengue, chikungunya and yellow fever.
The study was published online on September 1 in The Lancet.
To figure out where Zika might gain a future foothold, researchers used dengue as a model to examine patterns of people travelling from infected regions in the Americas to Africa and Asia and combined that with an assessment of local conditions, including the type and number of mosquito infestations.
Some experts caution that the study may overestimate people at risk because Zika may have caused undetected outbreaks in some of these countries in the past, which would have led to pre-existing immunity to the virus in Asia.
The virus in the Americas is an Asian strain that was responsible for a large outbreak in French Polynesia and other Pacific Islands in 2013 and 2014. “If there was broad circulation of this virus in Asia, then it could be that the risk of Zika spreading to Asia won’t be as bad as we think,” writes Dr Abraham Goorhuis of the University of Amsterdam, in The Lancet .