INFECTIOUS DISEASES

Chapter 15Pg. 400

INFECTIOUS DISEASE

Diseases caused and transmitted from person to person, by microorganisms or

their toxins. • Also called communicable or

contagious diseases.

What do you think? ■A hospital is a place where people can

easily pick up infectious diseases.– TRUE

■Antibiotics are among the few medicines that are effective against viruses. – FALSE. Antibiotics are useful

against bacteria, not viruses.

■Fevers are dangerous, especially when people have infections. – FALSE. Fevers are part of the

body’s defense against infection, and low fevers are not dangerous.

MicroorganismsBacteria

■Single celled organism.

■Grows/multiple in warm dark, moist environments.

■EX: – Tetanus– Tuberculosis– Lyme Disease

Viruses

■Not a cell, genetic material that can invade living cells – even bacteria.

■EX: – Influenza– Chicken Pox– Shingles– Pneumonia– Polio– Measles – Mumps

■ Pg. 404, Figure 15.4

Types of Bacterial Diseases■Tetanus – toxin produced by

bacteria within a wound. – Vaccine provided.

■Tuberculosis – bacterial infection of the lungs.

■Lyme Disease – bacterial infection spread by tiny deer ticks.

Other Pathogens that cause a variety of diseases.

■ Fungi ( yeast or molds)– Athletes foot

■ Protozoa

■ Parasites

■ Worms– Head lice

Mononucleosis “The kissing disease”

■Viral infection that resembles an upper respiratory infection. – Spread through saliva

■Symptoms – severe sore throat, fever, swollen glands, enlarged spleen, and infected liver.

■After full recovery, mono will not strike the same person again.

The Body’s Defenses

■First line of DEFENSE: – Skin – produces salty, acidic

sweat, which repels pathogens. It also have one-way pores that let toxins out, but won’t let pathogens in.

– Membranes – Mucus and chemicals.

Body’s Defenses continued

Demonstration

Antigen “ foreign invader” / FLU

T-cell “recognizes invader” and sounds an ALARM!

B-cells arrive and record shape of invaders. Then make antibodies.

Antibodies made so invader is remembered

and can be destroyed right

away.

HIV/AIDS HIV/AIDS

Antigen “ foreign invader” / HIV

T-cell “HIV hides inside cell, which remains safely away from immune system”

HIV multiplies as FAKE T-cells & invades more T-

cells.

After months or years, the

infection begins to destroy

immune system. All T-cells are

being destroyed.

INFECTIOUS DISEASE VIDEO

http://www.youtube.com/watch?v=M1pUoYBbEpI

Another way to FIGHT■Swelling of lymph nodes

■Fever– Cold viruses thrive and

multiply at temperatures between 86-95 degrees, but die off at higher temperatures.

– Activates immune system.

Food Infection/Poisoning■Salmonella – food borne pathogen

causing digestive system infections.

■Botulin Toxin – poison produced by bacteria in sealed cans, plastic packs, or jars or food.

■E.coli – toxin producing bacteria that can cause food-borne illness.– Diarrhea, severe cramps,

dehydration, and kidney damage.

Preventing Food-borne illness. ■Clean

– Hands– Wash cooking items in HOT water.

■Separate– Utensils to prepare different types of food. – Raw vs. cooked food.

■Cook– Meat & Seafood – 145 degrees– Ground meat – 160 degrees

■Chill– Do not eat cold dishes that have been in room

temperature for 2 hours or more – or 1 hour in hot weather.