環(huán)球英語(yǔ) — 291：Ebola - The Hidden Carriers
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Hello. I’m Rachel Hobson.
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And I’m Mike Procter. Welcome to Spotlight. This programme uses a special English method of broadcasting. It is easier for people to understand, no matter where in the world they live.
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Deep in the Democratic Republic of Congo (DR Congo) in central Africa, fifteen people lie on beds in a small shelter. Some have a fever, diarrhea and a skin rash. Others are worse. Their kidneys and livers are failing. They are bleeding heavily, inside and outside. Doctors and medical workers try to ease their suffering. But there is not much they can do. These people have Ebola. Most of them will die in just a few days.
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In a previous Spotlight programme, “Ebola: A Mystery Disease” we told of the history of the Ebola virus. Ebola has not killed very many people worldwide - but it is one of the most feared diseases in the world. People fear it because it is can be a horrible disease to suffer or even to see. The victims often bleed to death or die of shock. Ebola can spread easily in a community. It spreads through an infected person’s body fluids. And there is no cure or medical treatment for it. It kills 50 to 90 percent of people who do get it. In today’s Spotlight we talk more about Ebola. And we discuss a similar virus - the Marburg virus. We tell of an important theory about where these viruses come from.
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The Ebola virus and the Marburg virus are native to the African continent. They are from the same family of viruses - the Filoviridae family. And they both develop into severe kinds of hemorrhagic fevers. Hemorrhagic fevers damage the body’s system of controlling blood how blood flows. Without this control, humans cannot live.
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But Ebola does not only infect humans. It infects animals too - chimpanzees, gorillas and forest antelopes. In fact, many gorillas are dying from Ebola. The theory is that these animals got Ebola from another kind of animal. But scientists do not know which one.
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The scientists need to find Ebola’s “natural reservoir” . The natural reservoir is a plant, animal or substance where the virus lives and increases. The virus depends on this reservoir to survive. The Institute of Research Development (IRD) and other science organizations worked together to try to find the answer.
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Scientists decided to test the animals they found near the dead bodies of infected animals. They set up traps in different places in Gabon and DR Congo. It took a long time to catch and test the animals. But they did not give up. In total, they tested around one thousand [1000] small vertebrates - animals with backbones. Why? Well these vertebrates’ bodies have a defense system similar to humans. So any findings could also relate to the disease in humans.
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Finally the scientists discovered something very interesting. They found genes of the Ebola virus in three kinds of fruit bats - small flying animals that are only active at night. Ebola was living in the organs of these bats. Could they be the natural reservoir of Ebola?
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Scientists also found antibodies of Ebola in the bats. Antibodies are substances that fight particular diseases. The Ebola antibodies in the bats prevent the bats from getting sick. However, the antibodies do not kill the virus. So the bats spread it to other creatures.
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Researchers even believe they know how bats spread Ebola. During the dry season in central Africa food is more difficult to find. Bats and other animals go to the same places to look for food - fruit trees. They come close together as they gather to eat the fruit.
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The dry season is also the time when female bats give birth. Their bodies release fluids ?” blood and placenta. The fluids may fall on other animals and infect them. Or they may fall on parts of the tree that other animals touch. And the animals get infected. Then when humans hunt and eat the infected animals, they get sick too. Or they get sick from touching and working with the animals.
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This research was important in helping scientists discover more about Ebola. But they needed to look at Marburg too. The Marburg virus was first discovered in Europe. In 1967, scientists started to get sick. They were working in Marburg, Germany and in Belgrade in the former Yugoslavia. These scientists were working with animals from Uganda. Thirty seven people got sick, and seven of them died. Their insides turned to liquid. Since discovering the Marburg virus, doctors have seen the disease attack hundreds of people in Africa.
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So researchers decided to look for the Marburg virus in bats too. In September 2007, the IRD publicized its research. Scientists tested bats in Gabon. They found antibodies for the Marburg virus in Egyptian Rousette Bats. Egyptian Rousette bats are common in many parts of Africa! So, the Marburg virus could exist in many places that have not yet seen the disease.
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Researchers believe that Marburg can spread directly from bats to humans. In the year 2000, many people working in a goldmine in DR Congo were infected by the Marburg virus. Bats live in underground places such as mines and caves. And scientists found a large number of Egyptian Rousette bats in the goldmine.
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Since that time other miners have got sick in nearby countries. In 2007, researchers looked at a mine with infected bats in Uganda. In that mine many spaces were only three meters high. The humans and bats were very close together. So the scientists believe humans get Marburg from the bats’ waste and other liquids. Dr. Rollin from the US Centers for Disease Control said:
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“We think people can be infected by breathing, or having some bat waste on their skin, or in their eyes.”
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Dr. Rollin believes that people working in mines in Africa should wear special clothes to protect their bodies and faces.
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Do bats hold the answer to developing a cure for Marburg and Ebola? The evidence seems to point to them. But scientists have not yet found a whole live virus in any of the bats. They need to do this to be sure that bats are the reservoirs of these diseases. Until they can prove their theories, Ebola and Marburg will continue to remain a mystery.
