听力原文：M: Oh, it is terrible! Aboard Aerolineas Argentinas flight 386, 368 passengers were given pre-prepared food on their way from Buenos Aires to Los Angeles. W: Then what happened? M: A few days after arriving in Los Angeles, one passenger died, and 74 others were seriously ill. W: And what is the reason for that? M: According to Dr. Phillips, it was the highest single outbreak of cholera in the United States this century, and the airline passengers were the victims of this new epidemic of cholera, a disease not seen in Latin America since 1895. They were just a few of the more than one million people affected in 20 countries, including at least 10,000 who died in the following three years after 1991. W: Cholera? To the best of my understanding, that disease has been dead for some time now. M: But it has come back. Dr. Phillips says that cholera is by no means the only old infection on the comeback, and it is one of the major infections that are fighting back fiercely against man's attempts to control them. W: But what are the reasons for the comeback of so many dead diseases? M: Phillips says a single reason can't explain why a new disease appears or an old one returns, and usually a combination of factors are involved. W: What kind of specific factors? M: Dr. Phillips in his book Plagues on Our Doorstep presents some reasons. W: What are they? M: First, international travel and commerce. The cholera aboard flight 386 and mosquitoes living in imported tires are examples of these. Second, technology and industry. For example, the technology in Britain's processing industry was a likely contributor to the emergence of mad cow disease. Third, the breakdown of public health measures. Declining health resources have resulted in the erosion of once highly-valued health services. W: Well, that's just unbelievable! (26)