SINGAPORE — More than 300 people have been diagnosed with the Zika virus in Singapore this year, while the figure for Thailand has reached 200. Though the numbers of Zika cases in other Asian countries remain in the single digits, outbreaks in these two trade and tourism hubs could take a heavy economic toll. Such impacts are already being felt in Latin America. The spread of Zika there has resulted in around 1,800 cases of microcephaly, and the World Bank estimates that Zika could result in losses of around $3.5 billion to Latin American economies, or 1% of gross domestic product in tourism-dependent ones. In Asia, the main impact is likely to be felt in Singapore, which will host a Formula One Grand Prix race from Sept. 16-18. The event attracts not only regional motor sports fans but also corporate guests attending business meetings during the race week. The current Zika outbreak is the first ever in the city-state. Though it has not sparked any panic yet, the rapid spread of infection has reminded many residents of the SARS crisis of 2003, which saw economic activity contract 4.2% in the second quarter of that year. China, Singapore’s biggest source of tourists, issued an alert on Sept. 7 urging visitors to Zika-affected countries to take precautions against mosquito bites.