D ISEASES a disordered or incorrectly functioning organ, part, structure, or system of the body resulting from the effect of genetic or developmental errors, infection, poisons, nutritional deficiency or imbalance, toxicity, or unfavorable environmental factors; illness; sickness; ailment.

T WO MAIN TYPES OF DISEASES : Infectious Diseases – Diseases that can pass from one organism to another Examples: colds, flu, strep throat, malaria Noninfectious Diseases – Diseases/Conditions that are not spread from person to person. Examples: heart disease, diabetes, cancer

Organisms that cause infectious diseases are called Pathogens Pathogens make you sick by damaging individual cells in the body

F OUR M AJOR K INDS OF P ATHOGENS 1. Bacteria 2. Virus 3. Fungus 4. Protists

F OUR M AJOR K INDS OF P ATHOGENS 1. Bacteria – one-celled microorganisms a. Examples – strep throat, ear infections, food poisoning, tuberculosis, tetanus b. Cause disease by damaging body cells and producing toxins which damage cells. c. Can be treated with antibiotics which kill or slows the growth of bacteria d. Some vaccines have been developed to prevent some bacterial infections by stimulating the body to produce antigens that will recognize and kill bacteria before it can cause illness. Ex. Tetanus, Tuberculosis.

F OUR M AJOR K INDS OF P ATHOGENS CONT. 2. Viruses –tiny non-living particles much smaller than bacteria Examples – colds, flu, chicken pox, HIV/AIDS a. There are over 200 different cold viruses and 150 different flu viruses. b. Viruses cause disease by destroying individual cells as they multiply c. Some vaccines are effective against some viruses because they stimulate the body to produce antigens that will recognize and destroy some viruses before they can cause illness (ex. Influenza, Chicken Pox, Polio,) d. Colds and flu are often spread through direct and indirect contact with an infected person.

AIDS: A CQUIRED I MMUNE D EFICIENCY S YNDROME The virus that causes AIDS attacks the immune system and reduces the body’ ability to fight infections. People who have AIDS have a weakened immune system that cannot protect them from diseases that rarely affect others.

F OUR M AJOR K INDS OF P ATHOGENS CONT 3. Fungi – which include molds, yeasts, and other organisms a. Examples – Athlete’s Foot, Ring Worm, Oral Thrush 4. Protists – one-celled or simple many-celled organisms, such as amoebas and algae a. Example – Malaria (from infected mosquitoes)

H OW D ISEASES ARE S PREAD 1. Person to Person a. Direct Physical contact – kissing, shaking hands, hugging, etc. b. Indirect Contact – Sneezing, Coughing c. Colds and flu are usually spread by direct or indirect contact with an infected person

H OW D ISEASES ARE S PREAD CONT. 2. Contaminated Water, Food, or Objects – a. Contaminated Water and/or Food 1. Example – Lettuce, Green onions, Spinach – E. coli b. Contaminated Objects 1. Door knobs, desks, toilets, rusty nails

H OW D ISEASES ARE S PREAD CONT. 3. Animal/Insect Bites a. Animals – rabies b. Insects - Lyme Disease (from infected ticks), Rocky Mountain Spotted Tick Fever, Malaria (from infected mosquitoes) 4. Environmental Pathogens (soil, air, water) a. Tetanus from bacteria live in the soil or water b. Botulism bacteria (severe food poisoning) live in the soil and is common in improperly canned food.

I MMUNITY The body’s ability to destroy pathogens before they can cause disease. Vaccines contain weakened or killed pathogens. Vaccines work because they cause the body to produce antibodies against the pathogen. If the pathogen enters the body later, special cells recognize the pathogen and kill it before it can cause sickness.