PUTRAJAYA, Aug 29 — Malaysia must brace itself for the Zika virus, Datuk Seri Dr S. Subramaniam said today following the discovery of 41 confirmed cases in Singapore.

The health minister said there was a high risk that the virus would spread across the Causeway due to the number of Malaysians working in Singapore and the difficulty in detecting the disease that does not show signs of infection in up to 80 per cent of carriers.

"There is a possibility of the virus spreading into our country as we have more than 150,000 to 200,000 Malaysians returning to Johor from Singapore,” he said during a press conference at his ministry.

"Asymptomatic is a bigger problem because they do not know they have it in their body and they can be the cause to spread to other people. It is a risk.”

He urged those returning from countries with reported cases of Zika infection to voluntarily test themselves at major hospitals.

Dr Subramaniam also said the ministry will increase efforts in reducing the number of Aedes breeding grounds and increase monitoring in Johor.

The Zika virus is transmitted by the Aedes mosquito that it already responsible for dengue fever in Malaysia.

The virus can cause microcephaly, brain deformities, and other birth defects.

Yesterday, Singapore reportedly confirmed that 41 Zika virus cases were locally transmitted.

Last week, Bernama reported the Singapore Health Ministry as saying that a 47-year-old Malaysian was likely infected in Singapore since she had not travelled to any countries affected by the Zika virus.

The Singapore Health Ministry also said that the patient developed a fever, rash and conjunctivitis on August 25. The following day, she sought the advice of a general practitioner, who then referred her to Tan Tock Seng Hospital where she tested positive for Zika yesterday.

The national news agency also reported that she was hospitalised for observation and is currently recovering.