Chapter 17

1. Chapter 17 Infectious Diseases and Sexually Transmitted Infections:Risks and Responsibilities

2. Objectives • Discuss the risk factors for infectious diseases and how your immune system works to protect you. • Describe the most common pathogens. • Explain the major emerging and resurgent diseases affecting humans today. • Discuss the various sexually transmitted infections. • Discuss human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS).

3. Assessing Your Disease Risks • Risk factors you cannot control • Heredity • Aging • Environmental conditions • Organism resistance

4. Assessing Your Disease Risk – cont. • Risk factors you can control • Personal habits • Dosage, virulence, and where agent enters the body • Age at time of infection • Preexisting level of immunity • Health and vigor of immune system • Genetic factors controlling immune response • Nutritional status of host • Comorbidities • Environmental surroundings • Psychological factors

5. The Body’s Defenses Against Disease-Causing Pathogens Figure 17.1

6. Types Of Pathogens And Routes Of Transmission • Direct/indirect contact • Autoinoculation • Airborne contact • Food-borne infection • Animal-borne infection • Interspecies transmission • Water-borne • Insect-borne

7. Routes of Disease Transmission Table 17.1

8. Bacteria • Single celled organisms • Three major types: cocci, bacilli, and spirilla • Bacterial toxins cause disease • Common bacterial infections: • Staphylococcal – toxic shock syndrome • Streptococcal – strep throat • Meningitis • Pneumonia • Legionnaire’s disease • Tuberculosis • Periodontal diseases • Rickettsia-caused diseases

9. Viruses • The smallest of the pathogens, consists of a protein structure that contains RNA or DNA requires a cell host • Common cold • Influenza • Infectious mononucleosis • Hepatitis – A, B, C • Mumps • Chicken pox • Measles • Rabies

10. Is it a Cold or the Flu? Figure 17.2

11. Ways in Which Hepatitis A, B, and C Are Contracted Figure 17.3

12. Other Pathogens • Fungi – hundreds of species, uni- or multicellular plant organism: candidiasis, athlete’s foot, ringworm • Protozoa – single-celled organisms: trichomoniasis, giardiasis • Parasitic worms – largest of the pathogens, pin worms, tape worms • Prions – self-replicating, protein based agent: mad cow disease

13. Your Body’s Defenses • Skin – physical barrier against pathogens • Enzymes – complex proteins in sweat that creates inhospitable environment for pathogens • Mucous membranes trap organisms • Cilia – hair-like protrusions that sweep trapped organisms toward body openings so they can be expelled

14. Keeping Defenses Healthy Table 17.2

15. The Immune System • Immunity – a condition of being able to resist a particular disease by counteracting the substance that produces the disease • Antigen – any substance capable of triggering an immune response • Antibody – produced by the body and are matched to that specific antigen • Cell-mediated immunity – a grouping of lymphocytes that can attack and destroy the foreign invader

16. Body Response • Fever – a rise in temperature above 98.6°F • Results from toxins secreted by pathogens that interfere with the control of body temperature • Pain – early sign of injury • Referred pain – present in one location of the body although the source is at another location

17. The Immune Response Figure 17.4

18. Vaccines • Consists of a killed or attenuated versions of a disease-causing microorganism, or an antigen that is similar to but less dangerous than the disease antigen • Acquired immunity • Natural immunity • Active immunity • Passive immunity

19. Recommended Adult Immunization Schedule, by Vaccine and Age Group, 2006 Figure 17.5

20. Emerging And Resurgent Diseases • Factors: overpopulation, inadequate healthcare, drug resistance, increased international travel • Mad cow disease • Dengue and dengue hemorrhagic fever • West Nile virus • Ebola hemorrhagic fever • Severe acute respiratory syndrome (SARS) • E. coli 0157:H7 • Cholera • Hantavirus • Listeriosis • Malaria

21. ABC News: Infectious Disease Play Video | Infectious Disease

22. ABC News: Infectious Disease Discussion Questions: • What is the difference between an epidemic and pandemic? • What animals, other than birds, have been identified as having the “Bird flu?” • What strategies have the Thailand Ministry of Public Health and the Centers for Disease Control designed to monitor the spread of the Bird Flu in Thailand?

23. Factors Contributing to Emergent/Resurgent Disease Spread and Possible Solutions Table 17.3

24. Sexually Transmitted Infections • 15.3 million new cases reported each year in U.S. • More than 65 million people live with an incurable STI • 2/3 of all STIs occur in people 25 years of age or younger • 1 in 4 new STI infections occur in teenagers

25. Modes Of Transmission • Sexual intercourse • Oral-genital contact • Hand-genital contact • Anal intercourse

26. Signs or Symptoms of Sexually Transmitted Infections (STI) Figure 17.6

27. Chlamydia • Often presents no symptoms • Affects mostly women • If left untreated can affect • Men – prostate gland, seminal vesicles • Women – cervix or fallopian tubes • Both – arthritis like symptoms, damage to heart and blood vessels • Easily treated with antibiotics

28. Pelvic Inflammatory Disease (PID) • Term used to describe numerous infections of the uterus, fallopian tubes, and ovaries • Often results from an untreated STI • Symptoms include: abdominal pain, fever, unusual vaginal discharge • Left untreated increases risk for infertility, chronic pelvic pain, recurrent upper genital infections

29. Gonorrhea • 700,000 cases per year • Bacteria pathogen Neisseria gonorrhoeae • Primarily infects the linings of the urethra, genital tract, pharynx, and rectum • High risk are males aged 20 to 24; females 15-19 • Treatment with antiobiotics • If left untreated, can cause sterility

30. Syphilis • Caused by a bacterial organism • Progresses in stages • Primary – development of a chancre that disappears in three to six weeks • Secondary – 1 to 12 months after chancre disappears, a rash or white patches on the skin appear which last a few weeks or months • Latent – infectious lesions, infection can be passed on to fetus (congenital syphilis) • Late – heart damage, central nervous system damage, blindness, paralysis, dementia • Treatment - antibiotics

31. Pubic Lice • Small parasites that are usually transmitted during sexual contact • Lay eggs at the base of pubic hairs • Treatment – washing clothing, furniture, and linens • Usually takes 2 to 3 weeks to kill all larval forms

32. Genital Warts (HPV) • Genital warts caused by human papillomavirus (HPV) • Affects 5.5 million Americans per year • 2 types • Full-blown genital warts • Flat warts • 30% progress to precancerous cells • Treatment for genital warts – podophyllin, cryosurgery, simple excision, laser surgery, creams containing 5-fluorouracil, interferon injections

33. Candidiasis (Moniliasis) • A yeast like fungus caused by Candida albicans • Found naturally in the vaginal tract, become problematic when normal chemical balance is disturbed • Factors that affect chemical balance • Antibiotics • Changes in hormone levels due to pregnancy, breastfeeding, or menopause • Douches or spermicides • Sexual intercourse • STIs

34. Trichomoniasis • Caused by a protozoan • Many carriers experience no symptoms • Symptoms may include: foamy, yellowish, unpleasant-smelling discharge, burning sensation, itching, and painful urination • Transmitted by sexual contact and spread by toilet seats, wet towels, or other items with discharged fluids on them • Treatment – oral metronidazole

35. General Urinary Tract Infections (UTIs) • Caused by various factors • Invading organisms travel up the urethra and enter the bladder • Prevention is aided by diligent hand washing • Treatment depends on the organism

36. Herpes • Caused by virus • Genital herpes is caused by herpes simplex virus (HSV) • Two types of HSV • Type 1 • Type 2 • No cure for herpes, although some drugs can ease symptoms

37. Preventing Herpes Table 17.4

38. HIV/AIDS • Acquired immune deficiency syndrome affected 60 million people worldwide since 1981 • Human immunodeficiency virus causes AIDS • Over 38.6 million people are estimated to be living with HIV or AIDS • 4.1 million new cases were diagnosed worldwide in 2005

39. Women And AIDS • In 2005, women accounted for over 60% of AIDS cases in U.S. • AIDS is the leading cause of death in African American women aged 25 to 44 • Women have been underrepresented in clinical trials for HIV treatment and prevention • Factors for disparities: economically disadvantages, cultural norms, rape, sexual abuse, caregiving burdens, less education, passive role in negotiating safe sex

40. How HIV Is Transmitted • HIV enters the host from an infected host • Mucous membranes of the genitals and anus are easiest route of entry • Once inside the host, the virus begins to multiply • Virus begins to destroy helper T-lymphocytes • Virus changes the genetic structure of the cells it attacks • The body begins to produce antibodies

41. High Risk Behaviors • Exchange of body fluids • Injecting drugs • Receiving a blood transfusion prior to 1985 • Mother-to-infant (prenatal) transmission

42. Symptoms Of HIV Disease • Months or years after initial infection of HIV before symptoms appear • Immune system changes occur over years • May experience a number of opportunistic infections • Colds, sore throats, fever, tiredness, nausea, night sweats, generally appear as pre-AIDS symptoms

43. Testing For HIV Antibodies • ELISA test detects presence of HIV antibodies • Western Blot test is a more expensive confirmatory test • Positive results do not ensure the infected person will develop AIDS • Early detection is important so that infected individuals can receive immediate treatment

44. New Hope And Treatments • New drugs have slowed the progression from HIV to AIDS • Protease inhibitors block the HIV protease enzyme from cutting protein chains to form new viruses • Protease inhibitors are difficult to manufacture • No cure is known

45. Preventing HIV infection • Avoid risky behaviors • Take responsibility for your own health • Seek information from health educators or other health professionals

46. Tattoo and Piercing Safety Table 17.5