III. Replace the underlined words with their synonyms.

contagious, give rise to, attack, gain control of, classified, gain, passes, multiplication, predisposed

1. Many kinds of bacteria, viruses, and other microorganisms can invade the human body and caus e disease.

2. Pathogens take ove r some of the body's cells and tissues and use them for their own growth and reproduc tion.

3. Infectious diseases can be grouped according to the kind of patho­gen that causes them.

4. As a result, people infected with the virus become susceptible to certain illnesses that do not normally occur or that normally are not serious.

5. These pathogens obtain food by breaking down body tissues or by absorbing digested food from the intestines.

6. Most infectious diseases are comm unicable.

7. Occasionally, an infectious disease becomes highly contagious and sweeps through a community.

IV. Answer the following questions.

1. What are pathogens?

2. How can infectious diseases be grouped?

3. What organisms are called bacteria?

4. What diseases are caused by viruses?

5. What do you know about AIDS?

6. How do fungi, protozoans, and worms obtain food?

7. How do infectious diseases spread?

8. What conditions are called an epidemic, a pandemic, an endemic?

V. Fill in the words from the list, then make sentences using the completed phrases.

disease-causing, throughout, minor, life-threatening, highly, lifeless, electron

1. ____________ microorganisms

2. ____________ particle

3. ____________ infections

4. ____________ disorders

5. ____________ contagious

6. ____________ the world

7. ____________ microscopes

VI. Read the text and put each sentence into the correct place.

Some pathogens can survive for long periods on nonliving objects. Insects spread some of the most fatal infectious diseases. Many common infectious diseases spread as a result of close contact with a sick person.

How Infectious Diseases Spread

Infectious diseases can spread in three chief ways. They spread (1) by people, (2) by animals, and (3) by nonliving sources.

1) …………………………….. Such contact frequently takes place through coughing or sneezing, which expels tiny droplets of moisture that may contain pathogens. Diseases that spread largely through coughing and sneezing include colds, influenza, measles, mumps, pneumonia, tuberculosis, and whooping cough.

2) Fleas, mosquitoes, and other insects that feed on blood transmit many serious diseases. Mos- quitoes transmit encephalitis, malaria, and yellow fever in this way. In the same manner, fleas spread plague, and lice carry typhus.

3) …………………………….. These microorganisms can be transmitted by clothing, bedding, silverware, and other objects handled by sick people. Certain bacterial infections sometimes spread to hospital patients through contact with such contaminated objects.

Lead-in

I. The suffixes -en, -ify, -ize combine with nouns and adjectives to form verbs. Look at the following lists of adjectives and nouns. Put the corresponding verb in the space provided. The first one in each list has been done for you.

Adjective→	Verb	Noun→	Verb
hard	harden	sign	signify
stabile		hospital
Sick		class
intense		specialty
deaf		agony
Fat		quality
sterile		heart

II. The following suffixes combine with verbs to form adjectives.

-ed

-ful

-he

-ant

Look at the words printed in bold and put the appropriate adjective in the space provided. The first one has been done for you.

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