Infectious Diseases Ch. 13

Collaborative Questions Define Infectious (Communicable) Disease Examples?

What are some ways diseases can be spread? What is a pathogen? What is a virus? What are some ways diseases can be spread? What is happening in the body when an infection is present in a living organism? What is a vaccines How do they work?

Infectious (Communicable) Diseases Any disease that is caused by an agent that has invaded the body Can be passed from one person to another person, from food or water, from animals, or from something in the environment Examples: Colds, flu, tuberculosis, MRSA, Ebola

All infectious diseases are caused by: PATHOGENS Any agent that causes disease Bacteria, viruses, fungi, protists, parasites

Pathogens Bacteria: Tiny, single-celled organisms that live almost everywhere on Earth Most bacteria are harmless and help with bodily functions Bacteria in mouth, intestines Harmful bacteria make you sick when they grow on or in your body Example: Some give off poisons (tetanus/toxins) that damage cells Sinus infections Most harmful bacteria are killed by our immune system, others need antibiotics to treat and cure infections

Pathogens Viruses: Smaller than bacteria Disease-causing particles made up of genetic material surrounded by a coat of protein the virus finds a living “host cell” and forces it to reproduce and “attack” more cells Colds, flu, measles, AIDS

Pathogens Fungi (fungus) Protists Parasites Rickettsia Organisms that absorb and use nutrients from other living or dead organisms Mushrooms Athlete’s foot, ringworm Protists Larger and more complex than bacteria Malaria Parasites Animals—get their energy and nutrients by feeding on other living organisms Lice, tape worms, etc. Rickettsia Pathogens that resemble bacteria Invade cells of other organisms Enter humans through bites from fleas, ticks, or lice typhus

How are they transmitted (spread)? Person to person Airborne (sneezing, coughing, touching anything drops landed on) kissing, drinking from same glass, direct contact (tetanus) Dirty Hands Suck Food and water Contaminated food (from humans, from infected animal) Examples? Water from streams or lakes, sewage, Typhoid, cholera, dysentery Environment Pathogens are all around you—few can cause disease Tetanus present in soil Animals Pathogens live on/in animals Ringworm from pets, mosquitos carry malaria, yellow fever, encephalitis, ticks carry Lyme disease

How to treat… Bacterial diseases Viral Diseases Fungal Infections Antibiotics-medicines used to kill or slow the growth of bacteria Penicillin CANNOT be used to treat colds or viral diseases Antibiotic resistance: bacteria are no longer killed by a particular antibiotic Improper use=build up of antibiotic resistant bacteria Viral Diseases Not much is known, so most concentrate on relieving symptoms and stopping production of viruses inside cells Fungal Infections Over-the-counter or prescription medicine Protistan, parasitic Infections Prevention—good hygiene, sanitation

Protection Against Diseases read pgs. 638-644 Immune System- general and specific Network of cells, tissues, organs, and chemicals that fight off pathogens Physical and Chemical Barriers First line of defense Physical—skin (sweat and oil) and mucous membranes (mucus and cilia)block pathogens from entering the body Chemical—enzymes (stomach acid, tears)

Protection Inflammatory Response-2nd line of defense A reaction to tissue damage caused by injury or infections Prevents further tissue injury and stops invading pathogens Immune System- general Made up of different types of blood cells and proteins called antibodies-(act against a specific pathogen) Cells move through bloodstream and lymphatic system A network of vessels that carry a clear fluid called lymph throughout the body—pick up bacteria and viruses and delivers them to the lymph nodes Collection of WBCs in lymph nodes while fighting infection

Protection- specific Antigen-a substance capable of triggering an immune response Found on the surface of pathogens and in toxins Immune System White Blood Cells Primary job=defend against disease Phagocytes (to eat) A specific white blood cell that attacks invading pathogens Engulfs pathogens and then destroys them with chemicals (enzymes) Creates pus A collection of dead white blood cells and damaged tissue—may collect at the site of inflammation as a response to harmful bacteria Macrophages-a type of phagocyte that destroys pathogens by making antigens (recognized my WBCs) to trigger an immune response Result=IMMUNITY The stat of being protected against a particular disease

Protection- specific Lymphocyte A specialized white blood cell that coordinates and performs many of the functions of specific immunity T cells, B cells, NK cells Recognize antigens not made by the body (non-self) B cells- produce antibodies to neutralize the pathogen T cells- produce powerful enzymes to kill the infecting pathogen Helper T cells trigger production of B cells and NK cells NK Cells- attack and destroy infected cells **attack only infected cell—NOT pathogen

Protection Vaccines Substances made of killed or weakened pathogens or from genetic material introduced into the body to create immunity The body begins to make WBCs called memory cells If the specific pathogen enters the body , the memory cells and their antibodies fight the pathogen before it can cause disease May need boosters for vaccines Flu?

Questions With a partner, answer questions #1 and #3 on page 644 Then, write a story with a phagocyte as the main character. This story should be an imaginative description of a phagocyte joining the inflammatory response to stop invading pathogens after some kind of injury to the body. Your stories can be funny or sad, but all should accurately describe the strategy against disease.

TED Talks A next-gen cure for killer infections

Common Infectious Diseases Bacterial Tetanus Symptoms- Severe muscle spasms Transmission- Tetanus causing bacteria found in soil Prevention- vaccine and boosters Treatment- antibiotics Strep Throat Symptoms- sore throat, fever, yellow or white specks on tonsils Transmission- contact with mucus from infected person Prevention- avoid contact Meningitis-inflammation of membranes covering brain and spinal chord Symptoms- severe headache, fever, stiff neck, sensitivity to light, nausea Transmission- contact with saliva or mucus from infected person Prevention- vaccine, avoid contact Treatment- antibiotics—if caught early enough

Bacterial cont. Sinus Infection Symptoms- headache, tenderness of sinuses, thick greenish mucus, pressure in head Transmission- contact with mucus Prevention- avoid contact and allergens Treatment- ?? Salmonellosis- an infection of the digestive system Symptoms- headache, cramps, diarrhea, nausea, vomiting Transmission- eating contaminated food Prevention- thorough cooking, hand washing, refrigeration Treatment- OTC meds for symptoms, sometimes antibiotics

Common Infectious Diseases Viral Flu Symptoms- headache, sore muscles and throat, fever, vomiting, ect. Transmission- contact with saliva or mucus Prevention- vaccine and avoid contact Treatment- rest, fluids Cold Symptoms- sore throat, sneezing, runny nose, mild cough Prevention- wash hands, avoid contact Mumps Symptoms- pain and swelling of glands in throat, fever, headache Transmission- contact with infected airborne droplets and infected person Prevention- vaccine Treatment- see doc. Rest, fluids

Viral cont. Measles Mononucleosis Hepatitis Symptoms- fatigue, runny nose, cough, fever, small white dots in mouth, rash on body Transmission- contact with saliva or mucus Prevention- vaccine Treatment- see doc. Rest, fluids Mononucleosis Symptoms- fever, swollen lymph nodes, sore throat, weakness Prevention- avoid eating/drinking after infected person Hepatitis Symptoms- inflammation of liver, jaundice, fever, darkening of urine Transmission- contact with bodily fluids, contaminated food or water Prevention- vaccine for A and B, wash hands, avoid contact Treatment- see doc. Rest, meds, no cure for Hep. B and C

You are a scientist for the CDC and have just discovered a recent outbreak of a new disease. As the head scientist, it is now you responsibility to describe this disease, how it is spread, and how to prevent it. The following must be provided in your document: Name of disease Cause of disease Symptoms of disease Transmission of disease Prevention methods Treatment