Special Report: Zeroing in on the Zika virus

Race to produce vaccine thwarted by lack of data, world on brink of health emergency

Even as scientists race to uncover more about a little-known virus named Zika, the prognosis from health experts is not looking pretty.

The disease, spread by the Aedes aegypti mosquito and suspected of causing birth defects, is spreading across the Americas and could soon grip Asia, Europe and Africa.

A vaccine is likely to be years away, and discoveries from the science community about other havoc the virus can wreak, are all conspiring to turn this latest outbreak into what could possibly be the next global health emergency.

The World Health Organisation (WHO) is contemplating whether to declare it as one, as its officials met representatives from affected countries and experts yesterday.

Last week, the United Nations health agency already warned that the Zika virus was "spreading explosively" across the Americas, which could chalk up to four million cases this year.

Meanwhile, South-east Asia has been bracing itself for the likelihood of an outbreak. There has been one Zika-related case each in the Philippines, Cambodia, Indonesia and Malaysia since 2010, while seven cases emerged in Thailand between 2012 and 2014.

More could have gone undetected, said WHO officials, since symptoms are usually mild or similar to other mosquito-borne viruses like dengue and chikungunya.

The Health Ministry in Singapore has alerted doctors to be on the lookout for potential carriers, while the National Environment Agency will step up its vector control should a case emerge.

The virus might have been around since at least 1947, when it was first documented in Uganda's Zika Forest. Outbreaks have been reported previously in Micronesia and French Polynesia which are located in the Pacific.

But what is causing alarm now is the epidemic that has hit Brazil and which is quickly enveloping the rest of South America - and the fear that Zika can cause birth deformities. Since the beginning of last year, Brazil has witnessed a spike in microcephaly, a condition in which a baby is born with an abnormally small head and brain.

So far, nearly 4,000 cases have been recorded there, and while scientists cannot say the link to Zika is definitive, WHO chief Margaret Chan warned last week that the causal relationship is "strongly suspected". "The possible links, only recently suspected, have rapidly changed the risk profile of Zika, from a mild threat to one of alarming proportions," she said.

One theory on the current outbreak in Brazil is that the virus could have been introduced after a canoe race in Rio de Janeiro in August 2014, when competitors from various Pacific islands participated.

Seeing the surge in the number of microcephaly cases in Brazil, South American states like Colombia, Ecuador and El Salvador are asking women not to get pregnant until the outbreak is under control.

The US also issued a travel alert asking women of childbearing age to avoid countries where the Zika virus is present, and pregnant women to stay away from countries with outbreaks of the virus.

Zika may also cause other complications. Doctors said last week that babies with microcephaly in Brazil were also suffering damage to their eyes and possibly hearing, too.

Zika could also be the culprit behind Guillain-Barre syndrome, a rare neurological disorder that causes muscle weakness and paralysis.

Colombia and Venezuela have reported a spike in the number of cases, with Colombia recording 41 cases of Guillain-Barre syndrome that may be linked to Zika infections. Brazil, too, has seen an almost simultaneous rise in Guillain-Barre and Zika.

Scientists have a lot of catching up to do. While there is a good amount of information on dengue fever out there, the world is dealing with a "data vacuum" when it comes to Zika, Dr Cameron Simmons, professor of microbiology and immunology at the University of Melbourne's Nossal Institute for Global Health, told Bloomberg.

Sanofi Pasteur, the vaccine arm of the French drugmaker, has had its dengue vaccine - which it spent 20 years developing - approved only in December.

"There are too many unknowns about Zika to reliably judge the ability to research and develop a vaccine effectively at this time," Sanofi spokesman Mary Kathryn Steel told Bloomberg.

Experts have urged WHO to step up to the plate in the wake of its less-than-sterling showing during the far more sinister Ebola outbreak, with Dr Suerie Moon of the Harvard T.H. Chan School of Public Health asking WHO to coordinate various research and development efforts to avoid duplication, and to analyse sensitive information about the outbreak that governments must legally provide to the UN health agency.

"WHO should marshal the world's best science to communicate to an uneasy global public the ways that Zika can be controlled," she wrote in The New York Times on Jan 29.

"In this way, WHO could reassure the world that it is now firmly in the driver's seat."

Zika's story has only just begun.

FAQs on Zika

Q What is Zika?

A It is a disease caused by a virus transmitted by the Aedes mosquito. It was first detected in Zika Forest in Uganda in 1947 in a rhesus monkey, and in the Aedes africanus mosquito in 1948.

Very few cases of human infection were reported before 2007, when an outbreak occurred on Yap Island in Micronesia. Brazil has borne the biggest brunt of the disease so far, with an estimated one million people infected.

Q What are the symptoms?

A The incubation period is likely to be a few days. The symptoms are similar to other mosquito-borne diseases such as dengue and chikungunya: fever, skin rashes, conjunctivitis, muscle and joint pain, malaise and headache. Symptoms are usually mild and last between two and seven days.

Q Why are there outbreaks now?

A Deforestation, increasing urbanisation and rising temperatures have encouraged mosquitoes to breed. With the high volume of travel across countries, the virus has a greater chance of getting imported as well.

Zika is new to the Americas, so the virus can spread quickly there to a big population of susceptible hosts who have no immunity to it. Latin America is also known to have a large number of Aedes mosquitoes.

In South-east Asia, there have been a small number of cases detected in Cambodia, East Malaysia, Indonesia, the Philippines and Thailand in recent years.

Q How is it harmful?

A When French Polynesia experienced an outbreak in 2013, instances of Guillain-Barre syndrome linked to the viral infection were reported, as well as a spike in microcephaly, a rare condition in which babies are born with abnormally small heads.

Evidence is mounting in Brazil linking the virus to microcephaly, while Colombia and Venezuela are both reporting a jump in cases of Guillain-Barre syndrome - a rare disorder that causes muscle weakness and temporary paralysis. Most people recover from it.

No Zika-related deaths have been reported so far, according to the World Health Organisation.

Q Is it likely to spread to Singapore?

A The Health Ministry and National Environment Agency (NEA) say it is "inevitable" the virus will be imported into Singapore, given the high volume of travel by Singaporeans and tourists, and the presence of the virus in the region.

Aedes mosquitoes are also present here, making subsequent local transmission likely.

The NEA said it will boost vector control activities should a case be detected, while anyone found to have the disease will be admitted to a single room in a public hospital.

Q Is there a vaccine or a drug for Zika?

A No, as the disease was rare and mild up until last year.

Those infected are usually advised by doctors to get plenty of rest and drink lots of fluids, while pain and fever are treated with available medicines.

Scientists are currently studying how to produce vaccines, but it could take five to seven years before one is commercially available.

Q How can you protect yourself?

A The same way you would with dengue if you're travelling to countries affected by Zika - wear long, covered clothing and apply insect repellant.

At home, take precautions to prevent mosquitoes from breeding.

Tan Dawn Wei

• Sources: World Health Organisation, Centres for Disease Control and Prevention

Join ST's Telegram channel and get the latest breaking news delivered to you.

A version of this article appeared in the print edition of The Straits Times on February 02, 2016, with the headline Special Report: Zeroing in on the Zika virus. Subscribe