Malaysia reported its first case of Zika on Thursday, a woman who tested positive for the mosquito-borne virus after a visit to neighboring Singapore, where 115 people have so far been infected, many of them foreigners.
The 58-year-old victim had shown signs of a rash and fever one week after her return from Singapore on August 21, said Malaysian Health Minister Subramaniam Sathasivam.
"We are carrying out control measures against aedes mosquitoes near the woman's home to prevent the spread of the virus," he told a news conference.
The Zika virus, which has spread through the Americas and the Caribbean since late last year, is generally a mild disease but is a particular risk to pregnant women. It has been linked to microcephaly - a severe birth defect in which babies are born with abnormally small heads and underdeveloped brains.
The U.S. Centers for Disease Control and Prevention had said Singapore is the only Asian nation with an active Zika virus transmission. Officials in the city-state, one of the world's largest financial centers and busiest travel hubs, reported the first locally transmitted infection on Saturday and said on Wednesday the number had jumped to 115.
Singapore authorities detected infections in people living outside the initial outbreak area and have identified a potential second cluster. A pregnant woman was among the victims, they said.
"Over time, we expect Zika cases to emerge from more areas," Singapore's Minister for Health Gan Kim Yong said in a statement on Wednesday. "We must work and plan on the basis that there is Zika transmission in other parts of Singapore and extend our vector control efforts beyond the current affected areas."
Five Malaysians in Singapore had tested positive for Zika, including the latest victim's adult daughter, who works in Singapore, the Malaysian minister said.
Twenty-one Chinese nationals, 13 Indians, six Bangladeshis, and an Indonesian are also among the 115 cases of Zika reported in Singapore, foreign officials said.
Many are believed to be overseas workers at building sites in Singapore, although the Singapore government has not given details of the victims by nationality.
The United States, Australia, Taiwan, South Korea and Indonesia have warned pregnant women not to travel to Singapore.
The outbreak and advisories come as the tourism industry in Singapore already faces weak global economic growth. Singapore's Tourism Board said it was premature to consider any impact on the sector, adding it remained a "safe travel destination".
More than 55 million people pass through Singapore's Changi airport every year. In the first half of this year, tourism arrivals topped 8 million, around 1 million more than a year earlier.
Malaysia has asked people visiting Singapore to use repellent and cover up to avoid mosquito bites. Tens of thousands of people travel between the two nations each day, by boat, air and across two land border crossings.
Both Malaysia and neighboring Indonesia have stepped up protective measures following the Singapore outbreak, intensifying checks on people arriving from Singapore, introducing thermal scanners and posting paramedics at airports and border checkpoints.
Zika is carried by mosquitoes, which transmit the virus to humans, but a small number of cases of sexual transmission have been reported in the United States and elsewhere. A case of suspected transmission through a blood transfusion in Brazil has raised questions about other ways Zika may spread.
There is no vaccine or treatment for Zika, which is a close cousin of dengue and chikungunya and causes mild fever, rash and red eyes. An estimated 80 percent of people infected have no symptoms, however.