Tests on sick schoolchildren in China's northwestern province of Shaanxi have shown they were not infected by swine flu, a local official said Tuesday.

"They just caught a cold and they had completely recovered as of April 22," Liu Shaoming, head of the provincial health administration, told Xinhua in a telephone interview.

Liu's remarks came after the World Health Organization's China representative Hans Troedsson said earlier Tuesday in Beijing that the Chinese authorities were investigating "several suspected cases" of influenza in Shaanxi.

Medical examinations by the disease control center in Xi'an, the provincial capital, confirmed the sick children had caught B-type influenza, which is common in humans.

Liu's comments were confirmed by a report on the website of China's Ministry of Health on Tuesday.

A total of 60 schoolchildren and three teachers at the Qianwei township junior high school in Lantian County, showed symptoms of high temperature from April 14 to 16.

The local disease control center reported the situation to the municipal health bureau of Xi'an, which immediately dispatched officials to the site.

All those who were ill were sent home as soon as they felt sick and none were hospitalized as their symptoms were slight.

The school of 727 students was closed as of April 14 and classes resumed on April 22. No new cases have been found since at the school.

Speaking at a press conference after meeting with Chinese Health Ministry officials on the country's preparations in the event of a swine flu outbreak, Troedsson acknowledged appropriate actions Chinese authorities had taken in isolating students at home and closing the school. He also praised the openness and transparency of the Chinese government in reporting avian influenza cases to the WHO.

Shanghai stipulated nine measures Tuesday, including 24-hour monitoring by officials of the entry-exit inspection and quarantine bureau of arriving passengers and transport from Mexico, and arranging special paths for passengers coming from swine-flu countries for body temperature tests, said Xu Chaozhe, vice head of the bureau.

Those with high temperatures would be further examined and even sent to designated hospitals according to test results.

Shanghai airport receives about 35 flights from the United States and two from Mexico everyday, bringing about 7,200 people.

Jiang Hao, an inspector with the border checkpoint in Nanjing, capital of neighboring province of Jiangsu, which has adopted similar surveillance, said, "We will ask passengers from Mexico, the United States and other countries hit by the epidemic to take temperature tests upon arrival. We ourselves also attend regular training courses about swine flu and take measures to prevent the disease."

The island province of Hainan, situated off the south China coast, is on high alert for the flu. Two local hospitals have been designated to treat suspected cases.

Farmers who raise pigs in the central Henan, one of the country's swine exporters, are closely monitoring their herds after the province stepped up measures against it.

"Now I only use the swine feed produced by local companies," said Su Xinmin, a farmer in Xingyang City. "I am disinfecting my pig pens everyday in hope of seeing through this tough time without losing any stock."

Guangdong Province is examining pork products imported from the United States, according to the provincial inspection and quarantine bureau. About 22,475 tonnes of pork and pork products were shipped to Guangdong from the United States during the first three months of the year.

The agricultural and livestock authorities of Jiangxi Province, one of China's major pig providers, has called on pig raisers and authorities to reinforce farm disinfections and purchase equipment for better swine flu monitoring.

Pork sales remained normal in some supermarkets in Nanchang, the provincial capital. Some salespeople said the sector may not be seriously affected unless swine flu is detected in China's own market.

(Xinhua News Agency April 29, 2009)