SINGAPORE – Last Friday (Sept 13), the National Environment Agency confirmed three cases of locally transmitted Zika virus infection in Hemsley Avenue in Serangoon Gardens, bringing the total number of Zika cases this year to 10.

Infectious diseases experts said it is not surprising that a Zika cluster has re-emerged but a widespread outbreak here is unlikely.

The last cluster to form here was in July 2017.

Here is what you need to know about Zika.

Q. What is the Zika virus?

A. It is a virus infection transmitted by the bite of an infected Aedes mosquito, which also carries the dengue and chikungunya viruses.

It is generally a mild disease; four in five people who become infected with Zika do not show any symptoms but could be infectious.

Q. What are the symptoms?

A. They include a fever, an itchy rash, body aches, headache, red eyes and, occasionally, nausea and vomiting.

These usually develop within three to 12 days after the mosquito bite and often last between four and seven days.

Q. How is Zika spread?

A. The virus is spread to people mainly through the bite of an infected Aedes mosquito.

In addition, transmission between humans is also possible – a pregnant woman can pass Zika to her foetus during pregnancy or around the time of birth, and the virus can also be spread through sex.

Q. Who is at greatest risk?

A. Unborn babies are most at risk should their mothers become infected with the Zika virus.

Between 1 per cent and 10 per cent of women infected during pregnancy give birth to babies with defects. The most common defect is microcephaly, where the baby is born with a much smaller head, sloping forehead and damaged brain.

Q. Is there a cure?

A. At the moment, there is no cure or vaccine. Only the symptoms can be treated.

To avoid getting infected, use insect repellent and wear clothing that covers the body, arms and legs.

The public are also encouraged to do the five-step mozzie wipeout to prevent mosquitoes from breeding at home.

Q. Can I get Zika and dengue simultaneously? Does having one of the two ailments make me immune to the other?

A. Getting both Zika and dengue and from a single bite is theoretically possible but highly unlikely.

There is also a theoretical risk of getting infected with both viruses, but such a situation is very rare.

Entomological studies have shown that while both viruses can co exist in a mosquito, the chance of that happening is very rare.

Getting either Zika or dengue has not been shown to induce cross immunity.

Q. Why has Zika resurfaced in Singapore after two years of absence?

A. Zika exists in South-east Asia, Singaporeans travel extensively, and the Republic receives many global travellers – conditions that make it is easy to import the virus.

The same weather conditions and vector driving the current dengue epidemic can also cause a similar surge in cases of Zika.

Q. Can my pet get Zika or dengue?

A. The only known animals that can get sick from Zika are non-human primates, such as apes and monkeys, which may have mild illness with fever when infected.

There have not been any reports of pets or other types of animals becoming sick with Zika.

Current studies suggest that other animals do not contribute to the spread of Zika, and there is no evidence that Zika spreads to people from direct contact with animals.