Chapter 23: Communicable Diseases

Transcription

1 Chapter 23: Communicable Diseases

2 Infections may be Acute Short term Relatively severe course Chronic Long-term May last a lifetime (HPV, HIV, Herpes) May require treatment for acute infections

3 Infections may be Localized Confined to identified site Exhibit heat, redness, swelling & pain Systemic (general) Involve the whole body Symptoms include fever, fatigue, headache, etc.

4 What Causes Communicable Diseases? Small microscopic organisms, also known as. Pathogens invade the body and attack its and. Pathogens take many forms including,,,,.

5 How Communicable Diseases are spread.. The Chain of Infection Link #1: The Pathogen Disease Causing Micro-organisms Link #2: Reservoir Place where the pathogen lives & grows Link #3: Place of Exit Way the pathogen leaves the body Link #4: Method of Transmission Way the pathogen travels to a new host Link #5: Port of Entry Place that the pathogen enters the new host Link #6: Susceptible Host Host with little or no resistance to the pathogen

6 Link # 1: The Pathogen Disease by Type of Pathogen Viruses Bacteria Fungi Protozoans Rickettsias Common cold Influenza (flu) Viral pheumonia Viral hepatitis Polio Mononucleosis Measles AIDS Viral meningitis Chicken pox Herpes Rabies Bacterial foodborne illness Strep throat Tuberculosis Diptheria Gonorrhea Lyme disease Bacterial pinkeye Bacterial pneumonia Bacterial meningitis Athlete s Foot Ringworm Vaginal yeast infection Malaria Amoebic dysentery Sleeping sickness Typhus Rocky Mountain spotted fever Smallpox West Nile Virus

7 Link # 2: Reservoir Anyplace a pathogen can survive, grow or multiply ~ Plants, animals, soil, water, medical equipment ~ The human body is the most common reservoir ~ Carrier: person who carries & can spread the disease Link # 3: Place of Exit Path by which pathogen leaves the reservoir. Examples: Body Fluids Mouth & Nose Cough Break chain of infection by covering mouth & nose with tissue WASH HANDS!!!

8 Link # 4: Method of Transmission 4 Methods: Contact Direct (person to person) Indirect (object or surface) Droplet Airborne Ingestion of Contaminated Food or Water Vector Transmission: living creature, insects

9 Link # 5: Portals of Entry Path that Pathogen Enters the Host Any opening in the body can be a portal or entry Respiratory tract Ears, eyes Gastrointestinal tract Genitourinary tract Broken skin

10 Link # 6: Susceptible Host Person with little or no resistance to the pathogen Barriers to infection compromised Level of susceptibility depends upon: Age: infants & elderly at greater risk Nutritional status Stress Environment Pre-existing Conditions

11 The Immune System 2 Major defense strategies Inflammatory Response General, or nonspecific (works against all types of pathogens) Specific Defenses Works against specific pathogens

12 Inflammatory Response The inflammatory response is a reaction to tissue damage caused by injury or infection. It s purpose is to prevent further tissue injury and to halt invading pathogens. If you have ever had the area around an injury become hot, swollen, red, and painful, you ve experienced the inflammatory response.

13 The Immune Response The immune response is a complex interaction between your body and an invading pathogen. It can be broken down into eight distinct stages.

14 Eight Stages of Immune Response 1. Pathogens invade the body. 2. Phagocytes engulf the pathogen. 3. Phagocytes digest the pathogen and T cells recognize antigens of the pathogen as an invader. 4. T cells bind to the antigens. 5. B cells bind to antigens and helper T cells. 6. B cells divide to produce plasma cells. 7. Plasma cells release antibodies into the bloodstream. 8. Antibodies bind to antigens to help other cells identify and destroy the pathogens.

15 Stage 2 of Immune Response Phagocytes engulf the pathogen. Phagocytes are white blood cells. They are scavenger cells that are constantly on the lookout for pathogens to attack. Other types of phagocytes: ~ monocytes ~ neutrophils ~ macrophages

16 Stage 3 of Immune Response Phagocytes digest the pathogen and T cells recognize antigens of the pathogen as an invader. An antigen encodes the phagocyte and triggers the immune response by signaling for the helper t-cells to produce antibodies.

17 Stage 4 & 5 of Immune Response 4. T cells bind to the antigens. Types of T cells: ~ Helper T s - trigger the production of B cells & killer T s ~ Killer T s attack & destroy infected body cells. Not pathogens, just infected cells. ~ Suppressor T s coordinate the activities of other T cells. They turn off or suppress helper T s when the infection has been cleared. 5. B cells bind to antigens and helper T cells.

18 Stage 6-8 of Immune Response 6. B cells divide to produce plasma cells. 7. Plasma cells release antibodies into the bloodstream. ~ Antibody: a protein that acts against a specific antigen. Creates immunity to that specific pathogen. 8. Antibodies bind to antigens to help other cells identify and destroy the pathogens.

19 Role of Memory Lymphocytes Your immune system has a memory. Some T cells and B cells that have been activated by antigens become memory cells. These cells circulate in your bloodstream & through the lymphatic system. This is how you only get certain diseases one time can you think of an example??

20 Common Communicable Diseases Respiratory Infections (Viral & Bacterial) 1. Common Cold 2. Influenza 3. Pneumonia 4. Strep Throat 5. Tuberculosis Hepatitis 1. A commonly spread through contact with feces. Vaccine is available to prevent. 2. B - more serious than A, found in body fluids, spread by sexual contact. There is a vaccine to prevent. No cure. 3. C most common bloodborne infection in US, spread by direct contact with infected blood. No cure.

21 Common Communicable Diseases Disease Cause / Transmission Symptoms Treatment / Prevention Mononucleosis Virus attacks lymphocytes; spreads through direct contact Chills, fever, sore throat, fatigue & swollen lymph nodes Rest if tired Measles Virus spreads when an infected person coughs, sneezes, or talks; highly contagious High fever, red eyes, runny nose, cough, bumpy red rash usually on head or face No definite treatment; vaccine for prevention Encephalitis Virus carried by mosquitoes; causes brain to swell Headache, fever, hallucinations, confusion, paralysis If caused by herpes virus, medication Meningitis Virus or bacteria causes swelling of membranes covering brain Fever, severe headache, nausea, stiff neck Vaccine for bacterial. Antiviral med for other

22 Prevention Strategies Wash hands Handle food properly to avoid foodborne illnesses Eat a balanced diet and exercise regularly Avoid sharing eating utensils, makeup, combs, brushes & personal items Take care of yourself when you re sick (cover your mouth, wash your hands) Use mosquito repellant Practice abstinence from sexual activity Learn to manage stress. Stress makes you vulnerable to illness if you do not find ways to manage it effectively.

23 Questions??