INFECTIOUS DISEASES Chapter 15 Pg. 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.

Microorganisms Bacteria ■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 ■Second line of DEFENSE: –Immune system – help fight infection. ■Lymphocytes – white blood cells that are active in immunity. –T-cells – recognize the invader that cause illness. –B-cells – make antibodies ■Antibodies – produced to fight invaders. –Antigens – invaders/foreign substances in the body, such as viruses or bacteria, that stimulate the immune system to produce antibodies.

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 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

Another way to FIGHT ■Swelling of lymph nodes ■Fever –Cold viruses thrive and multiply at temperatures between 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.