Due to a swine flu case confirmed by China's Ministry of Health, authorities are urging passengers onboard May 20's Dragonair flight KA662 from Hong Kong to Fuzhou to contact their local center for disease control and prevention or other relevant public health agencies.

Despite the best efforts so far, while most passengers who shared the same flight with the confirmed swine flu patient have been tracked down by health authorities here in China, but authorities are still experiencing difficulties in locating some remaining passengers.