China has recorded its first case of the virus commonly known as swine flu, a 30-year-old man who flew last Friday from St. Louis to Chengdu, the Health Ministry said Monday. Chengdu city officials said they had located and quarantined more than 130 of the estimated 150 other passengers who had traveled with the infected man on a connecting flight from Beijing to Chengdu, the capital of Sichuan Province. The man, identified only as Mr. Bao, was returning to China from studies at the University of Missouri when he fell ill during the Beijing-Chengdu flight on Saturday, reported Xinhua, the official news agency. He twice tested positive for the virus, formally known as A(H1N1) influenza, after going to a Chengdu hospital. The Health Ministry said his itinerary began in St. Louis and took him through St. Paul, Minnesota; Tokyo; and Beijing. Mr. Bao is in stable condition in the infectious disease ward of a Chengdu hospital, city officials said Monday. His father and girlfriend, who met him at the Chengdu airport, have been placed in quarantine, as has the taxi driver who took him to the hospital. China has taken extraordinary measures to prevent the spread of the flu strain to the mainland since the first swine flu cases appeared in Mexico last month. The government quarantined hundreds of Mexicans shortly after the outbreak began, and Hong Kong officials isolated 286 guests and staff at a hotel after a Mexican guest fell ill. Separately, the Health Ministry isolated seven people on Saturday who had flown to Beijing and Shanghai after traveling to Tokyo on a flight with an infected person. The government also has barred direct flights from Mexico and banned imports of Mexican pork, despite assurances that pork cannot transmit the disease. Chinese officials appear determined to avoid a repeat of the 2003 epidemic of SARS, or severe acute respiratory syndrome, which killed hundreds in Hong Kong and the Chinese mainland after a slow response by the health authorities. But Mexico has complained that the Chinese measures unfairly target its citizens. It announced Sunday that 30 Mexican companies would boycott a food-industry event in Shanghai next week. Two additional deaths attributed to swine flu were reported over the weekend