HEALTH REPORT - How Antiviral Drugs Work
By Jerilyn Watson
http://language.chinadaily.com.cn/dialogue/voa/special/2004/02/0211.rm
This is the VOA Special English Health Report.
Here is a common situation: A person gets sick with a high temperature, muscle pain and a cough. The person goes to a doctor to ask for some antibiotics（抗生素）to treat the infection. The doctor says the person has influenza which is caused by a virus. Antibiotics are not effective against viruses. They only treat infections caused by bacteria. But there are newer kinds of medicines known as antivirals（抗病毒素）.
A case of the flu usually lasts a week or two. Scientists at the United States Centers for Disease Control say early antiviral treatment can shorten that time by about one day. But they say for this to happen, people must take the medicine within the first two days of sickness.
Four antiviral drugs are approved for use against influenza in the United States. They mainly fight infections in the breathing system. Each drug has possible side effects（副作用）. In the United States, a person must have an order from a doctor to receive these medicines.
Scientists say two of the four drugs are effective against the infection caused by the type A influenza virus. They are not effective against influenza type B. The other two drugs can treat both. One of these antiviral medicines, called oseltamivir, can also help prevent influenza.
Viruses invade cells and copy the genetic material inside in order to reproduce. Some antivirals work by preventing this process. Or they may interfere with the ability of the virus to connect itself to the cell. Other antiviral drugs prevent the virus from destroying the protective protein around a cell.
The first antiviral drugs were created in the nineteen-sixties. A number of new antivirals were in common use by the nineteen-nineties. Progress in the engineering of genes and the science of molecular biology made these new medicines possible. Some have helped patients suffering from diseases like hepatitis B in the liver. Other kinds of antiviral drugs are able to suppress H-I-V, the virus that causes AIDS, so a person lives longer.
Antibiotics are made from bacteria. The drugs contain organisms that damage the cells of other microbes that cause sickness. The British doctor Alexander Fleming discovered what is generally accepted as the first antibiotic, penicillin. That was in nineteen-twenty-eight. Penicillin did not come into common use, however, until the nineteen-forties.
This VOA Special English Health Report was written by Jerilyn Watson.
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