Communicable Diseases

Chapter: 8

Lesson: 1

Grade: 6

Communicable Diseases

Pathogens are living organisms or particles that can cause disease.

A communicable disease is caused by pathogens that can be spread from person to person.

Communicable Disease

Can spread in a short time- Throughout schools- Families

Types of Pathogens

Viruses- microscopic particles that can reproduce inside living cells, leading to such illnesses as:

- Colds- Flu- Hepatitis (types A, B, and C)

Types of Pathogens

Bacteria- one-celled organisms that live almost everywhere on earth.

Most are harmless or even helpful

Types of Pathogens

Many kinds of bacteria cause diseases such as:

- Strep throat- Gonorrhea- Tuberculosis- Lyme Disease- Anthrax

Types of Pathogens

Fungi- living organisms that have some characteristics of plant cells but cannot make their own food.

Fungi feed off living or non living organisms

Types of Pathogens

Fungi Some forms cause disease such as:- Athlete’s foot

- Ringworm

Types of Pathogens

Protozoa- One-celled organisms that are larger and more complex than bacteria.

Not all protozoa cause disease.

Some do, causing:- Malaria- Toxoplasmosis

How They Enter the Body

Pathogens can cause diseases when they enter a person’s body. They can enter in a number of ways, including:

Direct Contact- Touching- Kissing- Other close contact

Direct Contact Example:

Can you think of an example of how a pathogen can be spread besides direct contact?

How They Enter the Body

Indirect Contact- contact with objects used by a person who has a pathogen such as:

- Handrails- Doorknobs - Chlorine - Eating utensils

This is a common way of spreading a cold

Discussion Question

How might you contact a communicable disease on a trip to a shopping mall?

How They Enter the Body

Using a needle that has infected blood on it

- Through tattooing - Piercing body parts- Injecting a drug

How They Enter the Body

Inhaling air that has pathogens

Eating food that has pathogens

Drinking liquid that has pathogens

How They Enter the Body

Being bitten by an animal or insect that has pathogens

Your Body’s Defense Against Communicable Disease Our bodies have special systems that

help us from the invaders around us.

Immune system is a system of body organs, tissues, and cells that destroys pathogens.

- Provides 3 lines of defense that can stop many pathogens, before getting deep into the body.

Our First Line of Body Defense

Inside of body openings (nose, mouth) we have mucus membranes.

Mucus is a thick, sticky substance that traps some pathogens

The air passages where you breathe are lined with tiny hairs called cilia

Cilia trap some pathogens, which you then exhale or sneeze out.

Our Second Line of Body Defenses

This second line of defense can kill invading pathogens.

These systems include:- Acids in the stomach that can kill

pathogens- Fever- a higher-than-normal body

temperature that can kill pathogens

Our Second Line of Body Defenses Continued. . . White blood cells - fight pathogens that

cause infection and illness.

Some kinds of white blood cells form antibodies

Antibodies are protein substances in blood that can find, weaken, or destroy certain pathogens

Immunity- Third Line of Defense

The body makes antibodies after it is exposed to a pathogen

Antibodies remain to protect the person from future attacks by the pathogen.

Immunity or resistance to a particular disease.

Immunity- Third Line of Defense Some diseases have deadly effects, so it

is better to have a vaccine.

Vaccines are dead or weakened pathogens given for immunity.

Vaccine causes your body to make antibodies to fight the pathogen for a specific disease.

Immunity- Third Line of Defense Common childhood vaccines include:

- Hepatitis B- Polio- Diphtheria, pertussis,

and tetanus (DPT)- Measels, mumps, and

rubella- Varicella (chicken pox)

Discussion Question

What are ways that you can avoid catching or spreading a disease to others?

Avoiding Communicable Disease

Wash your hands for at least 20 seconds with soap and warm water:

- Before and after preparing food- Before eating- After using the bathroom

Avoiding Communicable Disease

Keep your fingers away from your eyes, nose and mouth.

Touching objects and then touching the eyes and nose is a common way of spreading cold viruses.

Avoiding Communicable Disease

Cover your mouth and nose with a tissue when you cough or sneeze.

Don’t share personal items, such as toothbrushes, drinking glasses, or bottles.

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