Section A

　　Directions: In this section, there is a short passage with 5 questions or incomplete statements. Read the passage carefully. Then answer the questions or complete the statements in the fewest possible words on Answer Sheet 2.

　　Questions 47 to 51 are based on the following passage.

　　The bacteria that cause a common food-borne illness show low drug resistance in Australia, unlike similar strains from the United States and Europe, a study has found. Scientists behind the finding say Australia's de facto ban on certain antibiotics in poultry (家禽) and other livestock helps explain why.

　　In the study, researchers analyzed samples of Campylobacter jejuni (空肠弯曲杆菌) bacteria from 585 patients in five Australian states.

　　Scientists found that only 2 percent of the samples were resistant to ciprofloxacin (环丙沙星), one of the group of antibiotics known as fluoroquinolonones. By contrast, 18 percent of Campylobacter (弧形杆菌) samples in U.S. patients are immune to fluoroquinolonones, which have been used in the U.S. to prevent or treat respiratory (呼吸的) disease in poultry for a decade.

　　The study, led by Leanne Unicomb, a graduate student at Australian National University in Canberra, was published in the May issue of the journal Clinical Infectious Diseases.

　　"The findings add to the growing body of evidence suggestive of the problems of using fluoroquinolonones in food-producing animals," Unicomb wrote in an email.

　　Campylobacter is the most common food-borne disease in the U.S. and many other industrialized countries.

　　People can contract the pathogen (病原体) by consuming undercooked poultry or meat, raw milk, or contaminated (被污染的) water.

　　Symptoms include fever, vomiting, and diarrhea (腹泻). In rare cases, the disease can trigger paralysis or death.

　　"In most industrial countries Campylobacter is more commonly reported than Salmonella (沙门氏菌), a better-known cause of food poisoning," Unicomb said.

　　"The number of cases of Campylobacter has been on the rise in Australia since the early 90's."

　　In the U.S., about 1.4 million people contracted Campylobacter infections last year, according to the U.S. Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia.

　　While the infection rate in the U.S. has dropped over the last decade, the bacteria have grown more drug-resistant.

　　According to the CDC, surveys between 1986 and 1990 found no signs of resistance to the antibiotics in U.S. Campylobacter infections. But by 1997, strains resistant to the antibiotics accounted for 12 percent of human cases. In 2001 the figure climbed to 18 percent.

　　Public health experts say many factors contribute to Campylobacter's drug resistance; the widespread use of fluoroquinolonones by U.S. poultry farmers over the past decade is one of them.

　　Fluoroquinolones were first approved for use in humans by the U.S. Food and Drug Administration (FDA) in 1986. In 1995 the FDA granted poultry farmers permission to the use the drugs in livestock. Last year the FDA banned the antibiotic from food-producing animals, citing the concerns raised by public health experts over drug-resistant bacteria.