SIAU MING EN Today Online 1 Sep 16;
SINGAPORE — A pregnant woman living in the Aljunied Crescent-Sims Drive area has been infected with Zika, the first such case here, as the outbreak surges into new areas — namely Bedok North Avenue 3, Joo Seng and Punggol Way.
As of noon on Wednesday (Aug 31), there were 24 new locally transmitted cases of Zika, while the Ministry of Health’s (MOH) “look-back” tracing — cases that were previously reported to have shown symptoms but were not tested for Zika — has turned up nine more cases.
In all, there are 115 locally transmitted cases to date.
Of the 24 new cases, 22 are from the Aljunied Crescent-Sims Drive and Kallang Way-Paya Lebar areas. One patient lives on Joo Seng Road, and one lives on Punggol Way, and neither have known links to the initial affected areas.
In the Bedok North Avenue 3 area are three cases, which were among cases that were confirmed on Tuesday, but their links to the Aljunied Crescent-Sims Drive cluster could not be ascertained then, said the MOH, which revealed these details during a press conference late Wednesday night.
One of them works in the Aljunied Crescent-Sims Drive area, while the other two have no known connection to the area. The ministry said they had symptoms within four days of each other, and therefore did not infect one another.
The pregnant woman, who was referred for testing by her general practitioner, lives with someone who also tested positive for Zika, although the ministry declined to elaborate on their relationship.
She has been sent for a review to KK Women’s and Children’s Hospital, and her baby’s development will be monitored by her doctor, said the ministry, adding she was “generally well”.
Zika infections during pregnancy have been linked to microcephaly, where a baby is born with an abnormally small brain and skull. Amniotic fluid testing can done to screen for Zika, but the MOH has previously noted that a positive test does not mean a baby will be born with defects.
A recent New England Journal of Medicine study found that the chances of an infected pregnant woman giving birth to a child with microcephaly was between 1 and 13 per cent.
The National Environment Agency (NEA) will be extending its intensified operations to stamp out mosquito breeding at Bedok North Avenue 3, which has over 6,000 premises. Apart from Housing Board flats, also in the area are Fengshan Primary School, Bethesda (Bedok Tampines) Church, and Fengshan Community Centre.
The agency has also activated partner agencies of the Inter-Agency Dengue Task Force — which comprises 27 government agencies and private organisations — to help with localised search-and-destroy efforts within the Zika clusters. For example, the town councils have stepped up on cleaning of potential breeding habitats, the Land Transport Authority has stepped up control operations in all work sites and flushed the drains in the Kallang Paya Lebar Expressway.
The existing Aljunied Crescent-Sims Drive cluster now covers 7,000 premises, and the NEA has inspected 5,500 of them, the authorities said. Forty-five breeding habits were destroyed. The NEA has also served notices on more than 500 inaccessible premises, and will enter them forcibly if the owners do not respond.
The news that Zika cases had reached their neighbourhood left residents living around Bedok North Avenue 3 worried. “Zika virus can be spread very fast,” said Mdm Selina Chong, a 37-year-old account executive, who said she would buy mosquito repellent as a precautionary measure.
Mr Muhd Amirul, 21, added: “The best is to just stay indoors.”
When TODAY went to Punggol on Wednesday, a group of NEA officers were seen, along with pest control companies like Rentokil Initial Singapore, Empire Cleaning and Pest Control. According to Madam Halimah Abdul, a mobile library assistant at Block 114 at Edgefield Plains, she saw thermal fogging being carried out around 9.30 am.
Meanwhile, Indonesia joined the list of countries that have issued alerts against travel to Singapore, which include Australia and South Korea. Its Health Ministry has also assigned 193 officials to stand guard at eight Riau Islands sea ports that serve routes to Singapore, including those on Batam, Bintan and Karimun, reported the Jakarta Post.
All passengers entering through the eight ports who have come from Singapore must also pass through a thermal scan to check their body temperature. ADDITIONAL REPORTING BY AMANDA LEE AND ILIYAS JUANDA
Zika outbreak: 33 more confirmed cases, new potential cluster at Bedok North Ave 3
Today Online 31 Aug 16;
SINGAPORE — A total of 33 more locally transmitted Zika cases were confirmed on Wednesday (Aug 31), bringing the total number of cases to 115. The Ministry of Health (MOH) announced the latest figures as it also identified a potential cluster of Zika virus infection at the Bedok North Avenue 3 area.
Of the 33 cases, 24 are new cases. Among them, 22 are from the Aljunied Crescent/ Sims Drive/ Kallang Way/ Paya Lebar cluster, said the MOH. Two cases had no known links to the affected area: One case lives at Joo Seng Road, and the other at Punggol Way.
The remaining nine cases were detected as a result of the MOH’s look-back testing of previous cases. Look back cases are those that were not referred by General Practitioners but were previously reported to have shown symptoms and were not tested for Zika.
The potential cluster at Bedok North Avenue 3 area involves three previously reported Zika cases. One of the cases works at the Aljunied Crescent/ Sims Drive area while the other two cases had no known links.
Vector control still mainstay in reducing spread of Zika: Dr Lam Pin Min
Channel NewsAsia 1 Sep 16;
SINGAPORE: Members of the community should play their part in keeping homes and premises clean to prevent mosquito breeding, as vector control "remains the mainstay" in reducing the spread of the Zika virus, said Minister of State for Health Lam Pin Min late Wednesday (Aug 31).
Commenting on the announcement that for the first time, a pregnant woman is among the latest Zika cases reported in Singapore, Dr Lam noted on Facebook that a positive Zika test does not give definite information on whether the foetus is infected or not.
The Ministry of Health has said there is evidence that Zika can cause microcephaly, a condition where a baby is born with a much smaller head than usual.
However Dr Lam said not every infected foetus will show neurological abnormalities.
"The risk of fetal abnormality will depend on which stage of the pregnancy the mother is in, with the highest risk likely in the first trimester," he wrote. "It is therefore imperative for the infected mother to be followed up regularly by the obstetrician, with serial ultrasound scans to monitor the growth and wellbeing of the foetus."
He added that pregnant women must take strict precautions to prevent mosquito bites and seek medical attention early if they have symptoms suggestive of Zika infection. The Ministry of Health has said testing for Zika is free at public healthcare institutions for pregnant women who shows symptoms of Zika such as fever, joint pain and rashes.
Q&A: Zika and dengue a potential double whammy?
TOH EE MING Today Online 1 Sep 16;
SINGAPORE — With the traditional dengue peak season looming ahead, Singapore could see a potential double whammy hit its shores. The onset of locally-transmitted Zika cases comes as the National Environment Agency (NEA) noted in its latest weekly dengue advisory that there has been a “steady increase” in the Aedes mosquito population since April. Earlier in February, it was reported that the number of dengue cases this year may exceed 30,000 — higher than the 2013 record when 22,170 cases were reported. This is due to factors like warmer temperatures, increased mosquito population and changes in the circulating virus.
TODAY spoke to several infectious disease experts to find out the implications for Singapore in having to grapple with two mosquito-borne viruses simultaneously.
Q: Is it possible for the same mosquito to carry both dengue and Zika viruses? What about someone being infected with both viruses at the same time?
Associate Professor Hsu Li Yang, programme leader of the antimicrobial resistance programme at the Saw Swee Hock School of Public Health: The major urban mosquito in Singapore, Aedes aegypti, is able to transmit both Zika and dengue viruses. However, I am not aware of any research that has attempted to infect a single mosquito with both viruses concurrently. In theory, it should be possible. There is a report documenting concurrent infection with dengue and Zika in two patients from New Caledonia. Both survived and the concurrent infection did not appear to result in a worse illness. There is also a report this year of a rare triple infection with dengue, Zika and chikungunya in a pregnant woman from Colombia. She also apparently did well, as did the unborn baby.
Prof Ooi Eng Eong, deputy director of Emerging Infectious Diseases Programme, Duke-NUS Medical School: The chance of getting two viruses are extremely small, so it’s more of a hypothetical question… Once the mosquito is infected, it also reacts to the infection, and that would inhibit a second infection… So even if mosquito infected with dengue and bites someone with Zika, the chance of it acquiring the Zika virus is very small. And immediately after a person recovers from a viral infection, for a limited period we are quite resistant to infections from other viruses because (the) immune system is already up and that’s what’s going to kill the viruses. So when new virus come in, it doesn’t survive. So to get two infections at the same time — it’s very uncommon. So each has their own concerns, I don’t think (you) can add the two together to become an even bigger problem.
Prof Ary Hoffmann, Entomologist at the Faculty of Science, University of Melbourne, Australia: This might be possible but it is expected to be extremely rare. A female would need to feed on a person with both viruses. Or take blood meals from one person with Zika and another with dengue (and then transmit this to a third person). But very, very few female mosquitoes would live long enough to do this
Dr Low Chian Yong, infectious disease expert in private practice: If you ask if it’s possible to happen concurrently, the answer is yes. But whether we have seen it, the answer is no. We’ve had chikungunya and dengue for quite a while, but I have not seen a co-current infection in a patient at the same time…. We’ve not have enough experience with patients with co-current illnesses to know the complications. But for adults, it does not cause bleeding like dengue, or severe myalgia like chikungunya, it does not cause encephalitis… For (most) adults it’s largely benign. We don’t have enough experience with patients to know the complications (that) might arise.
Q: Would there be a scenario where a person who has already contracted dengue might suffer from an even worse case of Zika?
Assoc Prof Hsu: This has been difficult to prove or disprove in a real world setting. However, in a study published this year by investigators from Imperial College London, it was shown that under laboratory conditions, the dengue antibodies in blood collected from patients that had recovered from dengue cross-reacted to the Zika virus (both are related viruses belonging to the flavivirus family), but were unable to neutralise it. Instead, they resulted in the enhancement of Zika infection in cell lines. These results seem to suggest that prior infection with dengue may result in greater vulnerability to Zika infection.
Dr Lam Mun San, Infectious Disease Physician, Mount Elizabeth Hospital: Possible as well. No one knows what happens in concomitant simultaneous infection but there are concerns that circulating antibodies to dengue can potentiate Zika infections.
Q: What are some of the issues that you foresee cropping up if dengue and Zika both hit?
Assoc Prof Hsu: The two diseases mimic each other (although dengue generally results in a more severe illness) to a considerable extent and therefore one may be mistaken for another. But the primary issue is that of a strain on the hospitals and healthcare system if the number of cases of both diseases escalates rapidly. Thankfully, this does not appear to be the case – the number of weekly dengue cases, while high, is actually similar or lower compared to last year’s figures. The hospitals have also been able to discharge Zika-infected patients relatively quickly, as the duration of viremia (when the patients are able to transmit the virus to mosquitoes, and hence potentially to other persons) is short.
Dr Leong Hoe Nam, infectious disease specialist at Mount Elizabeth Novena Hospital: Dengue and Zika come from the same family of viruses, and the test kit might have false positive results, as they have similarities, which means a person may have Zika, but is wrongly diagnosed as having dengue. Is there any danger with this? No, because the management is still the same, (just need) adequate rest and water, as the risk of death in Zika is extremely low.
Dr Low: However, in cases of sexual transmission, there could be a prolonged transmission period. In the literature, if you have a male patient infected with Zika, his semen has been reported to secrete Zika virus for up to 93 days. For women, the recommendation for them to stay abstinent is about eight weeks, so potentially sexual transmission might be a concern but we have to learn more about it.
Q: Why is there a situation of local transmissions going on in Singapore when elsewhere in the region it doesn’t seem as pervasive? What could be the reasons behind this occurrence?
Prof Hoffmann: Peak dengue season is associated with greater mosquito breeding activity, and the same species that transmit dengue also transmit Zika, leading to an increased risk if Zika is circulating in the human population. Might just be bad luck of course (e.g. chance arrival of a person carrying Zika into Singapore). And while Singapore has Aedes mosquitoes that can transmit the virus, mosquito populations in Singapore are likely to be lower than in many other areas in the region, so again this is unlikely to be a factor.
Dr Lam: We are in the midst of a dengue outbreak and we have the vector mosquitoes that can transmit Zika. There is also active surveillance and active testing which may account for the ‘high’ pickup rate.
Dr Leong: I think Singapore got hit because it’s a major port of call for many airline companies, and we have a ready pool of Aedes mosquitoes ready to transmit… I believe that Zika would probably exist in other neighbouring countries now. The reason is because they may not have detected it yet.
Dr Vernon Lee, Adjunct Assoc Prof at Saw Swee Hock School of Public Health: Our contact case tracing is robust, so we looked back and tried to actively look for cases. We have an efficient and rapid laboratory testing, with accurate results, which takes about four hours. Advisories are also sent to healthcare professionals in a timely manner, so doctors are then able to assist in this surveillance and detection of cases. If you add all these together, we are very much able to detect cases and report them.
Mr Laurent Renia, executive director of Singapore Immunology Network (SIgN): (Singapore cases) are not a lot if you compare it to Brazil … The key is the vector. All you need is one person that’s infected, and that’s enough. One is enough to start a mini-outbreak. There is nothing particular to Singapore in this matter, in fact there’s an even lower (Aedes mosquito) population compared to other places. As long as we have mosquitoes in Singapore, we will be prone to any mosquito-borne infection.
Ms Lisa Ng, Principal investigator at SIgN: At this point, it’s too early to comment. We really need more effort to understand it further, to do further research on serological tests (which look for antibodies in the blood).
SIAU MING EN Today Online 1 Sep 16;