. Read then answer the questions.
Colds and flu are caused by viruses. The infections are contagious, passed on by tiny droplets and hand contact. There are hundreds of different types of virus that can cause cold, which explains why children get repeated colds. Flu is caused by the influenza virus. There are three major types: A (often the cause of flu epidemics), B and C. The flu virus is constantly changing its structure, so new strains appear each year. We don’t have immunity to the new strains, which is why we can catch flu repeatedly. Anyone can catch a cold or flu. The peak season for colds is the colder winter months, not only because of the weather but because central heating dries out the normally moist nasal mucosa-an important defense against invading viruses. However, you can catch a cold at any time of the year; one particular type of cold virus thrives in the summer. Flu rarely occurs outside November to February in the UK. A cold causes a stuffy or runny nose, sneezing, sore throat, cough, mild fever and tiredness, lasting from two to four days. Flu is more severe with a high fever (usually 39oC or above), chills, headache, intense muscle pains, exhaustion, loss of appetites, cough and sometimes a blocked nose and sore throat. It may last a week or more and possible complications include pneumonia. Most cold don’t last long and need no specific treatment other than painkillers and simple measures such as decongestant rubs or vaporizers. Antibiotics are of no benefit. Zinc supplements may help to settle a cold more quickly. Children with flu can be given similar treatments, with lots of rest, medicine to bring down any fever and plenty of fluids to avoid dehydration. Lowering the temperature in the room can also be helpful when someone has a fever. Specific antiviral treatments for flu are now available, but generally these are only given to those at high risk of flu complications.
1. What are cold and flu caused by?
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2. Why do children get repeated colds?
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3. How many influenza viruses is flu caused by? What are they?
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4. Who can catch a cold or flu?
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5. Which season do people usually get cold the most in the year?
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6. What symptoms do colds often cause?
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7. How many days does a cold last?
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8. What symptoms does flu often cause?
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9. How long does flu last?
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10. When someone gets colds, what measures should be used instead of painkillers?
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Read the text and complete the comparison table below.
BACTERIA AND VIRUSES
Both bacteria and viruses can cause diseases, but they are different in many ways. Bacteria are living organisms. They can live in many places, such as soil, water, and the human body. The smallest bacteria are about 0.4 micron* in diameter. Some bacteria in our bodies are helpful, but some can cause infectious diseases such as tuberculosis** or food poisoning. Antibiotics are often used to treat infections caused by bacteria.
*7 metre = 1 million microns
**a serious lung disease
Viruses are tiny germs that cause diseases in people, animals, and plants. They can cause a range of illnesses, from the common cold or the flu to more serious diseases such as AIDS and Covid-19. As they are very small (0.02 to 0.25 micron), viruses can get into our bodies easily. They are not living things, so they need to enter our bodies to become active. Then, they start to grow and cause the infected cell to make millions of copies of the virus. Vaccines are often used to prevent the spread of diseases caused by viruses.
Bacteria
Viruses
1. Living or not when entering the human body?
living
not living
2. Which is smaller?
smaller
3. Examples of diseases they can cause
tuberculosis or food poisoning
common cold or the flu to more serious diseases such as AIDS and Covid-19
4. How to treat/prevent diseases caused by them?
antibiotics
vaccinesBacteria
Viruses
1. Living or not when entering the human body?
living
not living
2. Which is smaller?
bigger
smaller
3. Examples of diseases they can cause
tuberculosis or food poisoning
common cold or the flu to more serious diseases such as AIDS and Covid-19
4. How to treat/prevent diseases caused by them?
antibiotics
vaccines