Saturday, 3 September 2016

Singapore a role model in handling Zika outbreak: World Health Organisation

The Straits Times, 3 Sep 2016

The World Health Organisation (WHO) said Singapore represents a role model for countries in its handling of Zika cases, and praised the level of transparency shown here.

It also revealed that Singapore is expected to complete gene sequencing of the virus strain behind the cases by next week. This is to confirm if the virus is the Asian strain, which is behind outbreaks in Brazil and the Americas, and which has been linked with microcephaly.

Last Saturday, the authorities announced that a locally transmitted case had been detected in the Aljunied area. The number of infections stood at 189 as of noon yesterday - including 38 newly detected cases.

While 34 of the latest cases were linked to the Aljunied Crescent/ Sims Drive/Kallang Way/Paya Lebar Way cluster, the remaining four new cases were not associated with any existing cluster, the Health Ministry said. It did not specify any other locations.

So far, two pregnant women have been infected. While the Zika infection is mild for most people, it can have serious consequences for unborn children, who may develop microcephaly and be born with a much smaller head.

Speaking after a meeting of the WHO's emergency committee on Zika at its Geneva headquarters yesterday, its outbreaks and emergencies head Peter Salama highlighted the "enormous" amount of work Singapore put in over the last week to track and contain Zika's spread.

This includes "epidemiological work, lab work, public health work, including vector control, detailed follow-up including retroactive analysis of cases".

"We really have to congratulate the transparency and quick reporting the Government of Singapore has implemented in the case of this outbreak and hope that all other countries can do the same," said Dr Salama.

Yesterday, the National Environment Agency said there will be community activities over the coming two weekends to urge residents to fight Zika. Among other things, they should ensure that mosquitoes are not breeding in homes and remove stagnant water.

Zika virus in two Singapore cases not from South America, scientists say
By Carolyn Khew and Linette Lai, The Straits Times, 9 Sep 2016

Scientists here have confirmed that the Zika virus found in two locally transmitted cases in the Alju- nied/Sims Drive cluster was not from South America.

However, more research is needed in order to understand the link between the virus strains - not sequenced before - and other health conditions such as microcephaly and Guillain-Barre syndrome.

"This (the virus strains) seems like something that has been in our region for a long time but it doesn't mean the clinical outcomes and all that are not linked," said Associate Professor Raymond Lin, head of the National Public Health Laboratory at the Ministry of Health.

"Chances are that we have to assume they share fairly similar potential for how they cause disease."

Prof Lin, together with Dr Sebastian Maurer-Stroh, senior principal investigator at the Agency for Science, Technology and Research's Bioinformatics Institute, shared their findings yesterday after sequencing three cases of Zika found here.

The first was from a Singapore permanent resident found in May to have been infected after he came back from Brazil. Based on the sequence, his strain was similar to those found in South America.

The two other strains found in locally transmitted cases, however, likely evolved from a strain circulating in South-east Asia since the 1960s even though they share the same lineage with South American strains. They are believed to have originated in Asia.

Infectious diseases specialist Paul Tambyah said the Zika virus had not been detected in previous surveillance studies but could have been in Singapore all along.

"The main thing is that the link between the current Singapore outbreak and Brazil is remote - a few virus generations away," he added.

"What this specifically means is that no one returning from Rio or South America brought the virus into Singapore. It came in from somewhere else - maybe it was under the radar in Singapore all along or perhaps somewhere in South-east Asia."

Apart from helping to track the spread of the virus globally, the findings would be helpful for developing Zika vaccines.

The link between microcephaly and Zika surfaced after Brazil reported outbreaks of the virus. Infectious disease experts here agree that it is too early to conclude the strains detected here are less likely to cause birth defects.

There is no need for those who are pregnant to panic even though they have to be cautious, said Prof Lin. "If any pregnant woman is infected with Zika, we'll need to just follow up closely and see what the outcome is."

Protection key as much about Zika virus is unknown
WHO expert points out that people must not take needless risks based on unproven claims
By Salma Khalik, Senior Health Correspondent, The Straits Times, 11 Sep 2016

Some experts believe that being infected with Zika once confers lifelong immunity, but that is only an assumption, says infectious diseases expert David Heymann.

Dr Heymann, who chairs the World Health Organisation's (WHO) Emergency Committee on Zika virus, said experts assume there will be protection "because that's the natural way the body responds".

"But we don't know," he told The Sunday Times, adding: "What you know (about Zika) is important, but what you don't know is even more important."

Another unknown is whether being infected with one Zika strain protects against other strains. Both the Brazilian strain, which has caused many cases of microcephaly or abnormally small heads in unborn babies, and the one found in Singapore come from the same Asian lineage, though they are distinct and different from one another.

Dr Heymann, who is professor of infectious disease epidemiology at the London School of Hygiene and Tropical Medicine, said studies are ongoing to find out why the incidence of microcephaly is much higher in the north-eastern part of Brazil. Experts postulate that it could be due to co-factors, such as another organism or environmental pollutants.

However, Dr Heymann said that the link between Zika and microcephaly "is pretty well confirmed" and pregnant women and couples planning to have a child should be aware of this.

"The message to pregnant women is that they need to use deet or some insect repellent on their skin, wear long sleeves, pants and socks, and don't get mosquito bites.

"These are day-biting mosquitoes. They like to bite around the ankles and other places. I don't know why they bite ankles. I guess they are under tables when you sit down. But they certainly do bite the ankles as they are exposed in women."

Couples in the reproductive age "really need to think it through", he stressed. "They have to ask themselves, 'Do I think I can protect myself against bites from mosquitoes'. And if they think they can't, they have to consider alternatives, such as preventing pregnancy till the outbreak is over."

The risk of getting an abnormal foetus is "low but still present. And if it happens to you, it's terrible".

There is also confusion over how small a head has to be, to be classified as microcephaly, although the WHO has recently come up with guidelines. About 15 per cent of babies with microcephaly grow up normal, according to international literature.

Asked if couples should get infected early so they can have a baby later, in the hope they will then be immune, Dr Heymann replied: "I would love to be able to tell them that, but I can't.

"Nobody knows the answer. It's one of the areas of research that needs to be increased."

His advice: "People should never expose themselves to a disease because you don't know what might happen."

Someone who has been infected with dengue once, for instance, risks getting the more dangerous haemorrhagic dengue the second time.

As for adults, experts do not think Zika affects the adult brain. However, laboratory tests show that it can damage brain cells, so this is another unknown.

There is also the link with Guillain-Barre syndrome, where the body's immune system damages the nerves, causing rapid onset of muscle weakness. Zika seems to increase the risk of this.

To make matters worse, Dr Heymann revealed that there is now increasing evidence that infected mosquitoes can pass the virus to their offspring, which means the number of infected mosquitoes can increase rapidly since they would not need to bite an infected person before becoming a carrier.

A vaccine against Zika is coming, but is at least a year away, said Dr Heymann. There are at least 30 Zika vaccines in different stages of development, with two approaching licensing. But clinical trials have to be carried out and that will take time.

There is also work being done to develop a test for antibodies, or the body's response to an infection, which will be able to check if someone has previously been infected with Zika. Current tests are only able to check for antigens, or the foreign bodies from the Zika virus, which generally do not stay in the body for long.

Dr Heymann praised Singapore's efforts since the discovery of Zika transmission here: "Singapore has done exactly what it can do with the technology that exists, and it's really laudable."

And he expects the Republic will be able to contribute a lot to the understanding of the disease.

Singapore has already sequenced the virus here and found that it is actually a different strain from the virus circulating and creating havoc in Brazil, although what this could mean in the long run is still unclear for now.

"It's unfortunate it (a Zika outbreak) is occurring in Singapore but now, Singapore researchers can be of great help to the world."

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