'Matter of time' before Zika cases are seen in Singapore: Experts

Experts tell Talking Point that the mosquito-borne virus could spread to Singapore given how much people travel, but they say it is "fairly mild" and that it may not be as severe as dengue or chikungunya.
Channel NewsAsia 2 Feb 16;

SINGAPORE: The Zika virus could reach Singapore shores, but experts have said if patients do not suffer from complications, the illness may not be as severe as dengue or chikungunya, which have been reported in Singapore.

In an interview with Mediacorp’s current affairs programme Talking Point, Associate Professor (Adjunct) Lim Poh Lian, Head of Department of Infectious Diseases at Tan Tock Seng Hospital, described Zika as a “fairly mild” disease, but the concern is its association with microcephaly in newborns, which cause brain damage.

As there is currently no vaccine or drug for Zika, containing the virus would have to be in the form of controlling the mosquito population and protecting expectant mothers, added Associate Professor Ooi Eng Eong from the Emerging Infectious Diseases Programme at Duke-NUS Graduate Medical School.

The World Health Organization (WHO) had declared Zika a public health emergency due to its link to birth defects.

Zika is spread by the Aedes mosquito, which also transmits dengue fever. Symptoms of Zika virus include rashes and fever.

The interviews with the experts as follows:

Q: Does Zika have similarities with other mosquito-borne viruses like chikungunya or malaria?

Assoc Prof Ooi: In terms of the severity of the disease, if you just get straightforward Zika infection, it doesn’t appear to be as severe as dengue or even chikungunya, the one that spread in 2007 onwards, or malaria. But again, this association with microcephaly in babies is new. That needs a little bit more work for us to identify if Zika does indeed cause it and how it does it.

Q: Should Zika reach Singapore, what are the possible consequences?

Assoc Prof Ooi: I think because we have dengue, that tells us we have mosquitoes even though it is controlled to a large extent by NEA. But because it can spread in clusters, therefore we can expect that if Zika does reach our shores, we will get a Zika outbreak.

Question is, how severe would that outbreak be? And that answer I think is still uncertain. As I said if it was in the past where Zika outbreak has occurred, then you get fever with rash and all that. It’s probably not as bad as dengue and you recover uneventfully. Now this association with microcephaly is of concern. Therefore, if zika does reach our shores, how do you protect the expectant mothers? That is something we need to take a long hard look at it. At this point in time because there are no drugs against Zika, there’s no vaccine, mosquito control is the only way we can control Zika and preventing it from spreading.

Q: Are there lessons we can learn from our fight against the other mosquito-borne diseases?

Assoc Prof Ooi: At this point in time, the question is still how we can reduce the aedes aegypti population to a bare minimum. So that even if Zika does reach our shores, the chance of it spreading in minimal. So without the vaccine or drug it is still down to mosquito control. Again that’s why NEA is so vigilant in sending out messages about keeping households and all that free of mosquito breeding sites. Because ultimately that’s the only way to prevent the spread of diseases like dengue and Zika.

Q: By declaring Zika a public health emergency, what does this allow the WHO to do?

Assoc Prof Lim: Well, I think the first thing is that it allows coordinated international action to be brought to bear on investigations and control measures and the second thing is to raise public attention and draw resources into tackling the emergency before it becomes a larger emergency. This was one of the things that needed to happen earlier in the Ebola outbreak and WHO’s been proactive about trying to do that now.

Q: How concerned should Singaporeans be about the Zika virus?

Assoc Prof Lim: I mean the reality is that Zika is generally considered a fairly mild disease for most people who get it. Zika virus was first identified in Uganda in 1947 in the Zika forest and there have been sporadic outbreaks and infections occurring in Africa and Asia. The concern really right now is because of the microcephaly. We are trying to scientifically investigate to see if it’s related to a viral mutation and whether the transmission is because of changes in the mosquitoes, whether it is changes in the virus or both.

We haven’t seen any or many cases at all of Zika in Singapore. It is probable that we will see some because of globalisation and people travelling. Most of the cases will probably come in by importation, by travellers coming back who have been in Zika areas.

Right now the places where there is a lot of Zika spread is really in the Caribbean and in South America, so Brazil for example, Ecuador, Guatemala. And again, those are not as common in terms of where Singaporeans travel so the risk is relatively low and the only way you can get Zika, the main way that you get ZIka is by mosquito bites from the Aedes mosquito that is infected. It is theoretically possible to get it from blood transfusions and obviously if a pregnant mother is infected with Zika, her child can be infected as well.

Q: What is Singapore doing in terms of monitoring the worldwide spread?

Assoc Prof Lim: It is a matter of time before Zika cases are seen in Singapore, given how much people travel. However, what we’re doing in terms of monitoring it is what we call horizon scanning. We look at cases in other countries, we read the medical reports.

We are aware of the sporadic cases in Asia, including the one in Taiwan from a man who had travelled from Thailand. So we know that it can happen. In terms of control, what we want to do is try to reduce the risk of importations. So people who are travelling in countries with Zika outbreaks should practise mosquito bite prevention - wearing long sleeves, using insect repellent, reconsidering travel if you’re pregnant. Raise medical awareness so that doctors know to test for Zika with the appropriate travel history.

For more on the Zika virus, watch Talking Point on Feb 4, 9.30pm on Channel 5.

- CNA/xq

Could exposure to dengue help build immunity against Zika?
Experts who spoke to current affairs programme Talking Point say exposure to the dengue virus could give Singaporeans some level of protection against the Zika virus.
Channel NewsAsia 3 Feb 16;

SINGAPORE: Could Singaporeans’ exposure to the dengue virus ironically give them some measure of protection against the Zika virus, which is strongly suspected of causing birth defects?

Experts who spoke to Channel 5's current affairs programme Talking Point said this could be a possibility.

“Because they are closely related cousins, to our immune system, they actually look alike to some extent,” said Associate Professor Ooi Eng Eong, of the Emerging Infectious Diseases Programme at Duke-NUS Medical School.

While the “jury is still out” on how the immune systems of Singaporeans who have been exposed to dengue would respond to the Zika virus, Dr Ooi said: “At least from limited other studies that we have looked at, there could be some level of protection.

“Is it enough to prevent the outbreak? I think the safe answer is, probably not. But it may actually modulate the disease … We hope that if it does reach our shores, then our immunity with dengue would protect us to some extent.”

Adjunct Associate Professor Lim Poh Lian, head of the Department of Infectious Diseases at Tan Tock Seng Hospital, said: “It’s just purely a scientific hypothesis that some people may have less symptoms because of their background with related flaviviruses.”

“But what we do know is that 80 per cent potentially of people with Zika infection don’t even have symptoms,” she said, citing the South American countries which have a background of dengue and yellow fever.

On Monday, the World Health Organisation (WHO) declared the Zika virus an international “public health emergency”. It cited “strongly suspected” causal links to thousands of cases of microcephaly - in which babies are born with underdeveloped brains - in Brazil.

MILDER THAN DENGUE

Ironically, though, doctors consider Zika a milder disease than dengue or chikungunya. All three viruses are transmitted by the Aedes Aegypti mosquito.

Adjunct Associate Professor Lim Poh Lian, Head of the Department of Infectious Diseases at Tan Tock Seng Hospital, said: “Zika is a milder disease by and large for most people. The vulnerable population are potentially pregnant women. Our concern is not so much that the mother would have a bad outcome, but that we are seeing a link to babies born with abnormally small heads.”

No Zika infections have been identified here so far. If it does hit Singapore – and in Dr Lim’s view, that is only a matter of time – the priority would be to safeguard expectant mothers.

“The main concern is to protect pregnant women, so we don’t want it to get into the community where people who haven’t travelled might potentially get exposed,” said Dr Lim.

UNDETECTED CASES HERE?

That may be easier said than done, when 4 in 5 people with the Zika virus do not display symptoms. The health authorities here have acknowledged that “we cannot rule out the possibility that there are undetected cases”.

Dr Lim said such unwitting carriers of Zika “may not know to seek medical care or to get tested. That will pose problems for control, and so what we need is a lot of public awareness as well as medical awareness”.

Both Dr Lim and Dr Ooi were interviewed for an episode of Talking Point, “Zika: Protecting your family”, that airs this Thursday (4 Feb) on Channel 5.

Singaporeans have been advised to protect themselves from mosquito bites if they travel to Zika-affected countries; and to see a doctor if they develop symptoms upon their return. Pregnant women are also asked to reconsider their travel plans to the affected countries.

But both Dr Ooi and Dr Lim say, a key line of defence is to curb mosquito breeding.

Said Dr Ooi: “At this point in time, because there are no drugs or vaccine against Zika, mosquito control is the only way we can prevent it from spreading.”

Dr Lim said: “We really need the community’s help with the vector control efforts. The Government can do a lot, but they can’t do everything.”

Zika won't spread like dengue in Singapore: Expert
By Salma Khalik, My Paper AsiaOne 3 Feb 16;

THE Zika virus will come to Singapore but is unlikely to result in major outbreaks here in the way that dengue has, said an infectious diseases expert.

The virus has infected millions of people in South America, with Brazil claiming it is the reason why more than 4,000 babies have been born with abnormally small heads since October last year.

But Lim Poh Lian, who heads Infectious Diseases at the Institute of Infectious Diseases and Epidemiology at Tan Tock Seng Hospital, said that when Zika arrives here, it is likely to have a similar effect as chikungunya.

The first transmission of chikungunya in Singapore was in 2008 but numbers have remained low, peaking in 2013 with 1,059 cases. Last year, 42 people were infected.

To prevent Zika's spread, anyone with a confirmed infection will be hospitalised until tests show they no longer harbour the virus in their blood, Dr Lim said.

As both Zika and dengue have similar symptoms, she said a person would be suspected to have Zika only if he or she had been to an area where there is an outbreak.

A blood test would confirm this within 48 hours.

Zika is normally a mild disease, although it is feared to be dangerous to unborn babes if their mothers are infected.

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