In 1979, a doctor in Singapore noticed that hospitals were treating an unusual number of influenza cases. Influenza is sometimes called “ flu ” or a “ bad cold ” . He took samples from the throats of patients in his hospital and was able to find the virus of this influenza. T here are three main types of influenza virus. T he most important types of these are type A and type B, each of them having several sub-groups. A t the hospital the doctor recognized that the outbreak was because of a virus group A, but he didn ’ t know the sub-group. H e reported the outbreak to the World Health Organization in Geneva. WHO published the important news together with reports of the same kind of outbreak in Hongkong, where about 15-20% of the population had become ill. A s soon as the London doctors received the package of throat samples, they began to test them. T hey found that they could reproduce themselves at a very high speed. Continuing their careful tests, the doctors checked the effect of medicine used against all the know n sub-groups of type A virus on the virus. N one of them was of any use. H aving separated the virus, the two doctors now made tests on some specially selected animals. I n a short time the usual signs of the disease appeared. T hese experiments showed that the new virus spread easily, but that it was not the killer. S cientists, like the general public, called it simply ” Asian ” flu.