Communicable Diseases

Get out your workbook, find pg. 94

What is Disease?

A disease is an illness that affects the proper functioning of the body or mind. A disease that can be passed to a person from another person, animal, or object is called a communicable disease.

Diseases that cannot be caught from people, animals, or objects are called noncommunicable diseases.

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Causes of Communicable Diseases

The tiny organisms that cause communicable diseases are called pathogens.

There are many different types of pathogens:

• Bacteria• Viruses• Fungi• Protozoa• Rickettsias

When pathogens enter the body, an infection may result. Page 94

Types of Pathogens

An infection is a condition that occurs when pathogens enter the body, multiply, and damage cells.

Bacteria are tiny one-celled organisms that live nearly everywhere. Most types of bacteria are harmless, and many types live on and inside the human body. In fact, your body needs certain bacteria to work properly. Common disease caused by bacteria include strep throat, tooth decay, boils, bacterial pneumonia, and impetigo.

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Bacterial waste in water

A virus is the smallest disease-causing organism. Colds, flu, and hepatitis are caused by viruses. Viruses also cause diseases of childhood and adolescence, such as measles, mumps, and chicken pox. It is important to know whether a disease is caused by a virus or by another pathogen so that the right treatment can be given. In general, bacterial infections can be treated with antibiotics but viral infections cannot. Some viral infections are now treated with prescribed medications.

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Influenza virus

Measles RashMumps

Swelling of salivary glands

Protozoa are single-celled organisms that are usually harmless but that can cause certain diseases. Malaria is a disease caused by protozoa that live in certain kinds of mosquitoes. If an affected mosquito bites a human, the person will be infected. Water contaminated with protozoa can also cause infections.

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Fungi are primitive life-forms that feed on organic materials. Certain fungi live in the hair, nails, and skin. Fungi cause ringworm, an infection of the scalp and skin, and athlete’s foot, an infection of the skin between the toes.

Athlete’s FootRingworm

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Rickettsias are disease-causing organisms that resemble bacteria but multiply like viruses. They enter humans from the bites of insects such as fleas or lice. They can cause diseases such as typhus and Rocky Mountain spotted fever.

Louse Flea Page 95

How Pathogens are Spread

Illness can occur when a pathogen enters your body. Here are some risk factors associated with communicable diseases:

• Direct contact with an infected person.• Indirect contact with an infected person.• Contact with a vector.• Other contacts.

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Preventing the Spread of Disease

Preventing the spread of disease involves good personal hygiene and that starts with hand washing.

Protecting others involves taking actions to prevent the spread of pathogens. If you are sick, determine the contagious period, that is, the length of time when a particular disease can spread from person to person. Stay home from school and away from other people during this period.

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Causes of Noncommunicable Diseases

Communicable diseases are caused by the spread of pathogens.

Noncommunicable diseases are diseases that are not transmitted by pathogens.

Many noncommunicable diseases are:

• Chronic diseases• Degenerative Diseases

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Diseases Present at Birth

Some babies are born with physical or mental disabilities resulting from birth defects or genetic disorders.

The causes of many birth defects are unknown.Genetic disorders are caused by a defect in genes.

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Lifestyle Behaviors and Disease

Heredity, age, gender, and ethnic group are risk factors over which people have no control.

Many diseases are the direct or indirect result of harmful lifestyle behaviors, such as using tobacco or eating too many fatty foods.

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Diseases Caused by the Environment

These environmental substances can cause serious health problems or make existing health problems worse for some people:

• Chemical waste• Certain construction materials• Household chemicals• Secondhand smoke• Improper waste disposal• Radon• Carbon monoxide

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1.How many surfaces does the average person touch in 30 minutes?a. 10b. 40c. 100d. 300

2.What is the most germ-contaminated surface in the average home?a. Toilet seatb. Phone c. TV remoted. Light switch Journal

3.Which of these classroom surfaces has the most bacteria?a. Water fountain handleb. Doorknobc. Computer keyboardd. Student desktop

4.How long can viruses survive on common surfaces like doorknobs and staplers?a. 10 minutesb. 3 daysc. 2 weeksd. 1 month

5.How many bacteria are on the average student’s desk?a. 10b. 100c. 10,000d. 10 million

6.Regular soap and water can kill germs.a. Trueb. False

7.All bacteria are bad.a. Trueb. False

8.How many colds does the average kid catch a year?a. 1b. 4c. 8d. 10

9.How many bacteria are on the average sponge?a. 100b. 2500c. 600,000d. 7 billion

10.You can help stop the spread of germs at home and school.a. Trueb. False

Communicable Diseases

Journal1.What foods does your family have for

Thanksgiving? (Describe at least 3-4.)2.What is your favorite part of the Thanksgiving

meal? 3.What is your favorite part of Thanksgiving day?

(food, football, sleeping…)

Food item for Eagle Food Bank by Monday 11/24. Extra credit.

4. What if your parents told you today that you weren't going to be able to celebrate Thanksgiving…that they don’t even think they will be able to afford a can of soup or a box of cereal. What would your reaction be?

1. What is a communicable disease?2. What is a noncommunicable disease?3. List the five types of pathogens.

1.How many surfaces does the average person touch in 30 minutes?a. 10b. 40c. 100d. 300

2.What is the most germ-contaminated surface in the average home?a. Toilet seatb. Phone receiverc. TV remoted. Light switch Journal

3.Which of these classroom surfaces has the most bacteria?a. Water fountain handleb. Doorknobc. Computer keyboardd. Student desktop

4.How long can viruses survive on common surfaces like doorknobs and staplers?a. 10 minutesb. 3 daysc. 2 weeksd. 1 month

5.How many bacteria are on the average student’s desk?a. 10b. 100c. 10,000d. 10 million

6.Regular soap and water can kill germs.a. Trueb. False

7.All bacteria are bad.a. Trueb. False

8.How many colds does the average kid catch a year?a. 1b. 4c. 8d. 10

9.How many bacteria are on the average sponge?a. 100b. 2500c. 600,000d. 7 billion

10.You can help stop the spread of germs at home and school.a. Trueb. False