1. Infection and Immunity

2. Chapter 12 Infection and Immunity
Learning Outcomes:
Discuss the nature of infection, types of pathogens, and the course of infections
Describe the body’s defenses against infection
Discuss immunity and immunization
Describe common infectious diseases
Discuss the causes, transmission, symptoms, diagnosis, and treatment of sexually transmitted infections

3. Infection viruses protozoa
Infectious (communicable) diseases caused by pathogens which are disease-causing organisms
Types of pathogens include:
viruses protozoa
bacteria parasitic worms
fungi
Modes of transmission

4. Microbes & Pathogens
Most microorganisms are not pathogenic, some essential to our health and life
Microbes are either endogenous (originate inside the body or exogenous (originate outside the body)
Immune system normally recognizes and destroys invasive pathogens and rids the body of diseased or worn-out cells; however when system is compromised or overrun, infection can occur

5. Bacteria
Single cell organisms, live in soil, air, plants, and animals including humans
Harmful bacteria release toxins
Use nutrients from host to reproduce
Grouped in families: Staphylococci, Streptococci, Chlamydia, Rickettsiae
Typically treated with antibiotics; however some are becoming resistant (MRSA)
Vaccinations are available for some (DPT)

6. Viruses Contain DNA or RNA, “hijack” the cell
Some remain dormant for long periods; others reproduce quickly.
Enter the body through eyes, nose, skin, mouth, or genital tract
Antibiotic treatment is ineffective
Prevention including immunizations is most effective in combating

7. Other Pathogens Fungi – plant organism (yeasts and mold)
Infections typically occur on skin
Ringworm (fungal infection of hair, skin, nails)
Candida (yeast-like fungus)
diaper rash, thrush (use of antibiotics)
Protozoa – single-celled aquatic animals
Malaria and diarrhea – major health problems in tropical climates and developing countries
Parasitic Worms (helminths) – multi-cellular
Pinworms, tapeworms, flukes – Flourish in intestines;
can be round or flat, microscopic to several feet in length

8. Body’s Defenses First Line of Defense: Physical and Chemical Barriers
Skin Mucous Membranes
Cilia Chemical Defenders
Second Line of Defense: Immune System
Specialized white blood cells
lymphocytes, phagocytes, NK cells
Immune response:
Cell-mediated immunity
Antibody-mediated immunity
Nonspecific immune response

9. Specific Immune Response
If nonspecific response cannot destroy antigens, lymphocytes are recruited.
T-Cells [Helper T cells, Killer T cells, Suppressor T-Cells]
B-Cells [produces antibodies, memory cells]
Lymph nodes

10. Immunity & Immunization
Innate Immunity: mother’s antibodies in fetus/newborn, temporary and limited
Acquired Immunity: Develops after birth
Active:
Natural Acquired Active Immunity (NAAI)
Develop naturally after producing antibodies when infected with the pathogen
Artificially Acquired Active Immunity (AAAI)
Immunizations with weakened or killed pathogen – body produces antibodies
Passive: injected with antibodies

11. Immune System Disorders
Allergies: Hypersensitivity to normally harmless substances; triggers release of histamine – causing typical symptoms; anaphylaxis – severe reaction
Asthma: triggers include allergens, pollutants, stress
Autoimmune Disorders: immune system attacks healthy cells as if they were antigens
Rheumatoid arthritis, lupus, multiple sclerosis

12. Common Infectious Diseases
“Common Cold” – over 200 viruses
Influenza – viral
3 families type A, B, C – mutate – need annual flu shot
Pneumonia – viral or bacterial
Legionnaire’s Disease – deadly bacterial pneumonia
Tuberculosis – bacteria
high incidence among IV drug user, homeless, people with HIV/AIDS
Lyme Disease – bacteria spread by deer ticks
Mononucleosis – Epstein-Barr virus
More prevalent between years of age

13. Sexually Transmitted Infections
Transmitted through sexual contact including: vaginal or anal intercourse, oral sex, transmission from mother to child during child-birth and breastfeeding as well as contact with contaminated items
Bacterial STIs – can be treated, may be asymptomatic
Gonorrhea
Syphilis
Chlamydia – 2nd most common, can cause PID in women

14. Sexually Transmitted Infections
Viral STIs – no cure, treatments may provide relief
HIV/AIDS – long period from HIV infection to AIDS
Transmitted through contaminated blood, semen, vaginal secretions or breast milk
Genital Herpes
Transmitted by genital and oral contact
Infected women higher risk of miscarriage, vaginal birth dangerous for baby – C-section results
Viral Hepatitis – Hepatitis B, C, D – sexual transmission
Vaccine available for hepatitis B & D, B is mandated
HPV/Genital Warts
World’s most common, most will contract in lifetime
Can progress to genital warts – linked to cervical cancer
HPV vaccines available for both men and women

15. Sexually Transmitted Infections

16. Sexually Transmitted Infections