Multi-pronged strategy to tackle Zika: Gan Kim Yong

Multi-pronged strategy to tackle Zika: Gan Kim Yong

“The journey in our fight against Zika is likely to be a long one, because of the presence of Aedes mosquitos," said the Health Minister in Parliament on Tuesday (Sep 13).

SINGAPORE: There are 333 people who have tested positive for Zika as of noon yesterday, said Health Minister Gan Kim Yong in an update to Parliament on Tuesday (Sep 13). This included eight pregnant women, and involved seven clusters. Most of these people have recovered and are no longer symptomatic, he added.

Mr Gan also said that because Zika is a mosquito-borne disease with a majority of those infected asymptomatic, the Government will not isolate or hospitalise Zika patients. Efforts will instead focus on vector control.

Although Zika has been around since 1947, Mr Gan noted that it was only in Feb 2016 that “the World Health Organization declared that the recent cluster of microcephaly cases in Brazil, which are suspected to be linked to Zika, constituted a Public Health Emergency of International Concern”. The risk of microcephaly, which is a congenital condition that affects the development of the brain, means many pregnant women are "understandably anxious" about the Zika outbreak, he said.

In response to questions by MPs, Mr Gan outlined Singapore’s three-pronged Zika action plan involving preparation, response, and long-term management.

4,000 BLOOD SAMPLES WERE TESTED BEFORE FIRST CONFIRMED CASE

To prepare for Zika, the Ministry of Health (MOH) took several steps, including making Zika a notifiable disease under the Infectious Diseases Act from this January, working with partner agencies to prepare operational plans in case of an outbreak, and stepping up public education and issuing health advisories.

MOH also worked with the National Environment Agency (NEA)’s Environmental Health Institute to put in place a surveillance programme for Zika two years ago. In partnership with about 200 clinics, blood samples from selected patients with symptoms associated with Zika were collected, said Mr Gan. More than 500 samples a month were tested for Zika from this January, and close to 4,000 samples were tested between February and August, before the first confirmed case, he added.

ACTIVE BACK-TRACING WAS WHY ZIKA CASES JUMPED FROM 1 TO 41 WITHIN A DAY

In response to initial cases, MOH undertook screening of patients’ household members, and NEA deployed officers to conduct intensive vector control operations in affected areas. Mr Gan also touched on how MOH and NEA moved to actively detect cases and identify clusters to manage the spread of Zika.

“This active back-tracing was why the number of confirmed Zika cases increased from 1 reported on 27 August to 41 on 28 August. This sudden jump was surprising to some people, who wondered if these cases had in fact been identified earlier but held back by MOH. In reality, the number of confirmed new Zika-positive patients increased only by 5. The other 36 were from our proactive back-tracing of workers at the construction site (at Sims drive),” he told Parliament.

“Through the back-tracing, we also checked the onset of symptoms for each case to determine the epidemiology of the outbreak. The analysis showed that the earliest case had onset of symptoms on 31 July. Some people misinterpreted this as MOH having known of the first Zika-positive case since 31 July. This is not so. As I explained, we only confirmed the first locally transmitted Zika case on 27 August, and we released the information the same evening.”

NO MORE ISOLATION POLICY AND HOSPITALISATION FOR ZIKA PATIENTS

To manage Zika in the long-term, Mr Gan said that efforts will focus on vector control as it is a mosquito-borne disease. The Government will no longer practice an isolation policy as this has limited effect. “80 per cent of those with Zika are asymptomatic and... there are already mosquitoes in the community already carrying the virus,” he explained, adding that hospitalisation of Zika patients is also not necessary as most cases are mild.

Mr Gan reiterated that subsidized Zika testing is extended to all Singaporeans beyond the affected clusters. He also said that pregnant women will be supported as a special group, given the possible risks to their foetuses in case of infection.

Zika testing for asymptomatic pregnant women is not routinely recommended, but symptomatic pregnant women and those whose male partners are Zika-positive will be provided with free Zika tests at both public and private healthcare institutions if doctors assess that testing is needed, he said. Mr Gan also added that pregnant women who have tested positive for Zika will be referred by their doctors to an obstetric or maternal-foetal medicine specialist for counselling and subsequent follow-up.

“Regular ultrasound scans will be carried out to monitor the development of the foetus. Zika infection does not always result in abnormal foetal development,” he said, adding that microcephaly has been tracked by the National Birth Defects Registry since 1993, and that the MOH will work with our doctors to monitor the outcomes of babies born to women with Zika.

ZIKA FIGHT "A LONG ONE": GAN KIM YONG

Lastly, Mr Gan touched on public education and research efforts. Zika testing is currently done at the National Public Health Laboratory, NEA’s Environmental Health Institute and major public hospital laboratories, and there is no specific anti-viral treatment or approved vaccine for Zika at the moment.

"There are also ongoing research efforts in Singapore relating to Zika. Testing and
translating these to practical clinical use will take time," he said.

Earlier, the sequencing analysis of the Zika virus found in two patients from the ongoing outbreak revealed that it had sequences similar to the Zika strain which have been circulating in Southeast Asia since the 1960s.

“We cannot tell at this moment whether the viruses found here cause more or less severe disease than those in South America. Future research will be needed to shed light on this,” he said, adding that it is still “early days” to ascertain the long-term trend of Zika infections although the number of cases detected in recent days has been “coming down”.

“The journey in our fight against Zika is likely to be a long one, because of the presence of Aedes mosquitos here. Even if we can control the present outbreak, we will need to continue to guard against imported cases, as the Zika virus is still circulating among many countries, including several in the region. Therefore, as we tackle Zika, life must go on. By working together, we can succeed in managing Zika in the long-term,” he said.

Source: CNA/ll

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