INFECTIOUS DISEASES

Infectious disease: any disease that is caused by an agent that has invaded the body. Examples: Strep throat Pneumonia Flu Pathogen: any agent that causes a disease.

1. BACTERIA: TINY, SINGLE CELLED ORGANISMS; CAN LIVE INSIDE OR OUTSIDE THE BODY 2. VIRUS: MULTI-CELLED THAT CAN ONLY REPLICATE INSIDE THE LIVING CELLS OF OTHER ORGANISMS 3. FUNGI: ORGANISMS THAT ABSORB AND USE THE NUTRIENTS OF LIVING OR DEAD ORGANISMS 4. PROTIST: THEIR DNA IS ENCLOSED IN A NUCLEAUS INSIDE THE CELL; USUALLY SPREAD THROUGH WATER 5. PARASITE: COMPLEX LIVING CYCLE; CAN LIVE INSIDE INTESTINAL TRACT OR BLOOD STREAM TYPES OF PATHOGENS

Bacteria Among the first life forms to appear on Earth Present in most of its habitats (soil, water, acidic hot springs, radioactive waste, deep portions of Earth’s crust) More than 300 bacteria live in your mouth 40 million bacterial cells in a gram of soil; about a million bacterial cells in a milliliter of fresh water Good bacteria makes vitamins and bad bacteria give off poisons

Virus o Genetic material in virus contain instructions for making more viruses o Replicate only inside living cells

Some are harmless Some cause disease Fungus

Protist - Most are free living -Some parts of the world protists are the leading cause of death

Parasite -do not kill their host -generally much smaller than their host -will often live in or on their host for an extended period

1. PERSON TO PERSON -SNEEZE OR COUGH: THOUSANDS OF TINY DROPS OF SALIVA AND MUCUS IN THE AIR THAT CARRY PATHOGENS; TOUCH OR BREATHE THESE INFECTED DROPS -KISSING -DRINKING SEXUAL CONTACT 2. FOOD AND WATER (HEPATITIS A AND BOTULISM) -FOODBORNE DISEASE -ANIMAL CONTAMINATED FOOD 3. ENVIRONMENT -PHONE -MONEY -SOIL 4. ANIMALS - LIVE ON OR IN YOUR PETS -MOSQUITOS -TICKS (LYME DISEASE, ROCKY MOUNTAIN SPOTTED FEVER) How Are Infectious Diseases Spread?

How Are Infectious Diseases Treated? Bacteria Antibiotics: medicines used to slow or kill the growth of bacteria. Penicillin, tetracycline, streptomycin Antibiotic resistance: a condition in which bacteria can no longer be killed by a particular antibiotic. Improper use of antibiotics promotes growth of antibiotic-resistant bacteria Virus Viruses do not grow as living cells-cannot be treated with the same medications Antiviral medications concentrate on relieving symptoms and stopping the production of viruses inside the human cell Vaccines

How Are Infectious Diseases Treated? Fungus Over-the-counter anti-fungal medication Prescription medications (yeast infections) Protists Prevention is the best protection-maintaining good hygiene and sanitation Prescription medication

How Are Infectious Diseases Treated? Parasite Medicated shampoo etc. Prevention-don’t share brushes, wear others clothes/hats

How Does Your Body Fight Disease? Physical Barriers: bodies 1 st line of defense Skin: chemicals (oils and sweat) kill pathogens that settle on the skin Mucus membranes: soft tissue that line the nose, throat, digestive tract, urethra, and vagina; makes a slimy material (mucus) to trap pathogens Chemicals: sweat (acidic), stomach acid (kill bacteria), tears (contain protein that kill bacteria).

How Does Your body Fight Disease? Inflammatory Response: bodies 2 nd line of defense; when the protective barriers are broken and a part of your body becomes infected; the area around the injury becomes inflamed, and gets hot; shows the body is attacking the pathogen. Inflammation: a reaction to injury or infection that is characterized by pain, redness, and swelling. Pus: yellowish substance that builds up around the injury that contains dead and injured body cells that were fighting the bacteria and the dead and injured bacteria.

How Does Your Body Fight Disease? Immune System : bodies last line of defense; made up of blood cells and antibodies that move through the blood vessels and are within your organs Lymphatic system : a network of vessels that carry a clear fluid called lymph throughout the body; the lymphatic system picks up fluid from all over the body, sweeps up bacteria or viruses and carries them to your lymph nodes. Lymph nodes : filled with white blood cells that scan the lymph for pathogens. White blood cells : cells in the blood whose primary job is to defend the body against disease.

- protect yourself, keep body healthy -eat a healthy, balanced diet -drink water -exercise regularly -get regular medical checkups -get vaccinated What Can You Do To Stay Well?

Common Infectious Diseases! BACTERIAL MENINGITIS: inflammation of the spinal cord membranes SALMONELLOSIS: usually caused by food infected with salmonella bacteria SINUS INFECTION STREP THROAT TETANUS: “lockjaw” usually causes severe muscle spasms

Common Infectious Diseases Viral Flu Cold Mumps: affects salivary glands Measles: childhood infection caused by a virus Mononucleosis Hepatitis: inflammation of the liver; hepatitis C mainly spread through sexual contact

Common Infectious Diseases Fungal Athletes foot Jock itch Ringworm

Common Infectious Diseases Protists Amebic dysentery: infected food and water Malaria: mosquitos

Common Infectious Diseases Parasites Head lice Hookworms: found in the intestines of animals and humans; could cause anemia in humans Tapeworms: mainly caused by eating undercooked meat of infected animals