Introduction to Disease

What is a pathogen?

Disease-producing

microorganism and

toxin

VIRUS

Viruses exist for one purpose only: to reproduce. To do that, they have to take over the reproductive machinery of suitable host cells.

Can be transmitted through air, food, water, body or sexual contact, and contact with contaminated surfaces.

VIRUS

Diseases caused by a

virus can not be

cured, but the

symptoms can be

treated. Vaccines can

also be administered.

Examples: Ebola,

HIV, HPV (Genital

Warts)

BACTERIA

Bacteria live on or in just about every material and environment on Earth from soil to water to air, and from your house to arctic ice to volcanic vents. Each square centimeter of your skin averages about 100,000 bacteria. A single teaspoon of topsoil contains more than a billion (1,000,000,000) bacteria.

BACTERIA

Bacteria can be spread

from person to person

in many ways.

Through air, food,

water, body or sexual

contact, and contact

with contaminated

surfaces.

BACTERIA

Can be treated with

an antibiotic.

Many to most

diseases caused by

bacteria can be cured

with an antibiotic.

Examples: E.coli,

strep. throat, TSS,

pink eye.

FUNGI

Fungi include single-

celled creatures that

exist individually—the

yeasts—and

multicellular bunches,

such as molds or

mushrooms.

Fungi usually grow

best in environments

that are slightly acidic

FUNGI

Fungi absorb

nutrients from living or

dead organic matter

(plant or animal stuff)

that they grow on.

Some fungi are quite

useful to us. (Bakers

yeast and antibiotics)

PROTISTS: PROTOZOA

The word protozoa

means "little animal."

Perhaps the best-known

protozoal menace is

Plasmodium <plaz-mo-

dee-um>, the parasite

that causes malaria. This

terrible disease leads to

about 800,000 deaths

each year worldwide.

Parasitic Worms

Tape Worm Hookworm

Pinworm

Rocky Mountain

Fever Lice

The Course of a Disease

1. Incubation – Invasion of the

pathogen….may not know you’re sick

2. Prodrome - Onset of symptoms

3. Clinical – Immune system in full battle

4. Decline – Pathogen almost killed off.

Memory cells develop

5. Convalescence – Repair of the body, body

returns to normal.

T-Cells and B-Cells

1. Invaders (pathogens) enter body

2. T-Cells (from Tyhmus Gland) recognize

there is an invader

3. T-Cells call on B-cells to help make

antibodies to kill off invader.

4. Antibodies kill off invader and store in

memory the type of invader (pathogen) so

the next time they come back they are

more easily killed off.

Chain of Infection

Reservoira "place to live", usually a human or animal (host)

PathogenThe organism that is capable of causing illness

Place of ExitA “way out, “ humans = body openings; droplets in person

containing pathogen, LIKE A SNEEZE

Chain of Infection

Susceptible HostSomeone/thing that has little or no resistance to the pathogen

Port of Entrymust find a way to get INTO the new host

Method of Transmissionmust have a way to travel to its host

Ways to break the link of Infection

Kill the Pathogen (Medicine)

Prevent contact (quarantine)

Prevent Escape (Cover your mouth when you cough)

Prevent Transmission (control disease)

Block the Ports (Band-Aids, Kleenex, cover mouth)

Resistant Host: stay immune