HURRICANE IN US COMPLICATES EFFORT

A resident leaves a community garden as a worker fogs the area at a new Zika cluster area in Singapore, Sept 1, 2016. [Photo/Agencies]

Meanwhile, in south Florida, where nearly 50 cases of Zika have been reported in non-travelers, officials said they trapped the first mosquitoes that tested positive for the virus, further confirming reports of local US transmission.

"This find is disappointing, but not surprising," Florida Commissioner of Agriculture Adam Putnam said in a statement. "Miami-Dade County, the City of Miami Beach, and state and federal partners will continue to work aggressively to prevent the spread of Zika," Putnam added.

That work is likely to be seriously hampered by a hurricane expected to hit Florida overnight, as high winds will make aerial insecticide spraying impossible and standing water in its aftermath will provide added mosquito breeding sites.

The Singapore outbreak and travel warnings come just two weeks before the Singapore F1 motor-racing Grand Prix, a major sporting and tourist draw. The race promoter said planning for the event is going ahead "as per normal".

Singapore's Tourism Board has said it is premature to consider any impact on the tourism industry, stressing the tropical city-state remains a "safe travel destination".

More than 55 million people pass through Singapore's Changi airport each year. Tourism arrivals topped 8 million in the first half of this year, around 1 million more than a year ago.

China is trade-dependent Singapore's top overseas market, and the Zika outbreak coincides with a dip in overall exports and slowing economic growth in both countries.

"If this continues, certainly it will have a negative impact, but it's hard to quantify in percentage terms or dollar value," said Francis Tan, an economist at United Overseas Bank in Singapore.

The Zika virus, which has spread through the Americas and the Caribbean since first being detected in Brazil late last year, is generally a mild disease but can cause microcephaly, a rare birth defect that can lead to serious developmental problems, and has also been linked to other severe fetal brain abnormalities.

The World Health Organization has also linked Zika to Guillain-Barre, a rare neurological syndrome that causes temporary paralysis in adults.