Make Your Way 6, Schulbuch mit Audio-CD und CD-ROM

Read the newspaper article and choose the best answers to the questions on the next page. 2 Clues in the deadliest ues? Killer in uenzas of the past have spread from birds to humans. Could it happen again? Leigh Dayton investigates. It was a frightening time. A southern city had already been infected badly, and checkpoints were quickly set up at border crossings. Travel- lers were quarantined , and local travel was restricted. Schools and churches were closed. Health authorities rushed to develop a vaccine , and residents were ordered to wear face masks, but people kept dying. SARS? The Hong Kong flu? A look into the possible future of the bird flu threatening Asia? None of these. This was Sydney in 1919 in the grip of the Spanish flu pandemic . By the end of the year, 11,500 Australians had died from it. Australia was not alone. The World Health Organization estimates that at least 40 million people died of the Spanish flu, an especially nasty respiratory infection . It was so fierce that infected lungs filled with bloody fluid as the victim quite literally drowned to death. The Spanish flu was one of the worst outbreaks in history (similar flu epidemics such as the 1957 Asian flu and the 1968 Hong Kong flu also claimed about 1 million lives each). It’s not surprising that scientists have worked for years to discover where it came from, why it spread so easily, and what made it so deadly. The answers are becoming increasingly relevant today as avian flu kills millions of birds in Asia (so far with few human deaths). No one wants a repeat of 1918–19. A recent report in “Science” magazine claims to have found some answers. Using samples taken from victims of the 1918 influenza A (H1), an international team have defined the three- dimensional structure of molecules called haemagglutinins (HA), which sit on the surface of the virus cells. These HAs attach to receptors on healthy cells, allowing the virus to invade. Researchers compared the 1918 HA to the HA from the 1957 Asian flu (H2) and the 1968 Hong Kong flu (H3) and found that the 1918 flu jumped from birds to humans. Their comparisons suggest that unlike today’s Asian bird flu, the 1918 virus spread easily from birds to people because it kept its avian HA while adding human HA. In other words, the virus didn’t mutate from a bird disease into a human one. It became both. The discovery of the HA ngerprint and the fact that the original haemagglutinins are so different from the modern H5 variety has given hope that the present Asian bird flu may not evolve into a disease that spreads easily between people. However, there are fears that it could always mutate. Almost 75 per cent of new human viruses have animal origins. The list includes diseases like HIV/AIDS, Ebola, and influenzas such as the Spanish flu and its descendants. The incubator for dangerous inter-species disease exchanges is usually a pig, an animal able to pick up bugs from both people and birds. If a pig gets cross-infected with human and bird diseases, the organisms can exchange critical bits of genetic material. The new virus can take off, moving quickly from pigs to people and back to birds. If this happens, widespread transmission is almost certain in the crowded markets of southern China, where people and animals crowd together, and hygiene is not always maintained. If animal experts keep an eye out for a Spanish- flu-like fingerprint in avian and pig viruses, public health officials could be one step ahead of potentially dangerous viruses. If they don’t, anything might happen. SARS (Severe Acute Respiratory Syndrome): Schweres Akutes Atemwegssyndrom Ebola: Infektionskrankheit mit oft tödlichem Ausgang; vorwiegend in Afrika zu finden 179 5 Compact unit 5: From the medical world Nur zu Prüfzwecken – Eigentum des Verlags öbv