Zika cases detected in Woodlands: What you need to know about the virus

SINGAPORE -

Two Zika cases

have been confirmed in Woodlands Street 11 and Street 32 on June 19.

The National Environment Agency (NEA) said enhanced surveillance has revealed persistent Zika virus signals in the area, which suggest that it is an area with likely Zika transmission. The Zika virus has been found in wastewater or mosquito samples collected in the vicinity of the reported cases.

A check on the NEA website showed that as at June 18, there were no Zika clusters in Singapore.

Here is what you need to know about the virus: 

What is Zika, and how is it transmitted? 

Zika is a viral infection spread mainly through the bite of an infected Aedes species mosquito, which also carries the dengue and chikungunya viruses. 

It can be transmitted through sex, transfusion of blood and blood products, or from mother to foetus during pregnancy.

There is no noticeable pattern as to when Zika cases tend to peak.

The symptoms of Zika and dengue are similar. The viruses can be differentiated by virological tests. 

What are the symptoms, and how is it diagnosed? 

Only one in five people infected with the virus displays symptoms. The most common symptoms are fever, rash, headache, joint and muscle pain, and red eyes. 

The symptoms usually develop between three and 12 days after the mosquito bite, and often last between four and seven days. Nausea and vomiting may also occur.

Individuals who suspect they have contracted Zika should see a doctor quickly, advised NEA.

A reverse transcriptase-polymerase chain reaction (RT-PCR) test uses blood and urine tests to determine the infection.

Zika infection in blood can be detected between five and seven days of the onset of symptoms, and in urine within 14 days of the first appearance of symptoms. 

Why do pregnant women need to be more careful? 

Unborn babies are at greatest risk should their mothers get infected with the Zika virus. 

Between 1 per cent and 10 per cent of women infected during pregnancy give birth to babies with birth defects. 

The most common defect is microcephaly, where the baby is born with a much smaller head and often a smaller brain that might not have developed properly. Other birth defects include difficulty swallowing, hearing loss, and vision problems and seizures. 

Not all babies born with congenital Zika virus will have all of these conditions. Some babies develop long-term health problems later on in life. 

Is there a cure for Zika, and how can its transmission be prevented? 

There is no known cure for the Zika virus, but symptoms of the infection can be treated. 

To avoid getting infected, people are advised to use mosquito repellant and wear clothing that covers the body, arms and legs.

NEA also advises the public to prevent mosquito breeding by removing stagnant water at home and in surrounding areas. Stagnant water in potted plants should also be emptied regularly. Sleeping under mosquito nets and in rooms with wire-mesh screens can also help keep out mosquitoes.

When was Zika first discovered? 

According to the World Health Organisation (WHO), the first notable outbreak of the virus was in 1952. It was first identified in monkeys in Uganda in 1947. WHO declared the virus a public health emergency in 2016.

The first imported case of the virus in Singapore was in May 2016. The first local cluster was detected in August 2016 in the Aljunied area, with a total of 298 cases. The outbreak was contained in four weeks. 

According to NEA’s website, about 72,000 gravitraps are currently deployed across Singapore. 

There have been a total of seven laboratory-confirmed Zika cases in Singapore as at June 12, 2025. There were 13 recorded cases in 2024.

Pregnancy and the Zika virus

Is a pregnant woman at higher risk of contracting the virus?

There is currently no evidence that suggests pregnant women are more vulnerable to the Zika virus. However, the effects of the infection are more severe should a pregnant woman contract it. 

The unborn child can develop a range of birth defects such as microcephaly and other issues later in life. 

Is the baby at risk throughout the pregnancy, and does being infected affect the risk of future pregnancies?

Zika-associated birth defects are more common in infants born to women with exposure to the virus early in the pregnancy. 

The highest risk of Zika-associated birth defects is with infections that occur during the first and second trimesters of the pregnancy. 

If a non-pregnant woman contracts the virus, future pregnancies are unlikely to be at risk. 

Are there any tests that can be done to determine if a pregnant woman is infected with Zika? 

The RT-PCR test, which looks for genetic material of the virus in blood or urine, can be used to determine if a pregnant woman is infected. If a pregnant woman is tested positive or inconclusive for Zika, she will be referred to a maternal foetal medicine specialist for counselling and management. She will be closely monitored and offered regular foetal ultrasounds. The healthcare professional may suggest amniotic fluid testing. 

If a woman is pregnant and has recently visited or works or lives in a Zika-affected area in Singapore, what should she do?

She should take strict precautions against mosquito bites. There is no need to see a doctor if she is well. If she has symptoms of a possible Zika virus infection, she should seek medical attention immediately and consult an obstetrics and gynaecology doctor.  

SOURCES: World Health Organisation, National Environment Agency, Communicable Diseases Agency Singapore, US Centres for Disease Control and Prevention, European Centre for Disease Prevention and Control