1. Chapter Eleven: Preventing Infectious Diseases
Image source: The McGraw-Hill Companies, Inc./Jill Braaten

2. Infectious Disease Transmission
Pathogen: A disease-causing agent
Epidemic: A highly significant increase in the number of cases of an infectious illness existing in a given time period in a given geographical area
Pandemic: An epidemic that has crossed national boundaries, thus achieving regional or international status
Example: HIV/AIDS

3. Pathogens Viruses Prions Bacteria Fungi Protozoa Rickettsia
Parasitic worms

4. Chain of Infection
Figure 11.1 The Chain of Infection

5. Chain of Infection Agent: Causal pathogen
Reservoir: Pathogen’s environment
Portal of exit
Mode of transmission
Direct
Indirect
Port of entry
New host

6. Stages of Infection Incubation stage Prodromal stage Clinical stage
Decline stage
Recovery stage

7. Body Defenses Mechanical Cellular-chemical (“immune system”)
Figure 11.2; The Body’s Defense Systems

8. Divisions of the Immune System
Cell-mediated immunity
T cell-mediated
Humoral immunity
B cell-mediated
Acquired immunity
Naturally acquired immunity (NAI)
Response to naturally occurring pathogen
Artificially acquired immunity (AAI)
Response to immunization
Passively acquired immunity (PAI)
From extrinsic antibodies

9. Immune Response
Figure 11-3 The Immune Response

10. Immunizations
Vaccinations should be given against the following infectious conditions:
Chicken pox
Meningococcus
Pneumococcal infection
Childhood diarrhea
Diphtheria
Whooping cough
Hepatitis B
Hepatitis A
Haemophilus influenza type B
Tetanus
Rubella (German measles)
Measles (red measles)
Polio
Mumps

11. Immunizations Recommended for Adults
Figure 11-4 Immunizations Recommended for Adults

12. Nosocomial Infections
Infections spread in conjunction with the delivery of health care services
Between 32, ,000 deaths/year are attributed to these infections

13. The Common Cold (Acute Rhinitis)
Acute upper-respiratory-tract infection
Caused by different viruses
Common symptoms; usually last several days
Treatments manage symptoms but do not cure the infection
More severe symptoms may indicate flu, pneumonia, or another infection
Prevention: Handwashing

14. Influenza Acute viral infection More serious than common cold
Especially dangerous for young children, pregnant women, older people
Annual vaccination
Risk of spread of highly virulent Avian and H1N1 influenza

15. Tuberculosis Bacterial infection of the lungs Symptoms
Chronic coughing
Weight loss
Spread through coughing
Requires long-term treatment with antibiotics
Antibiotic-resistant strains are a concern

16. Pneumonia Infectious respiratory conditions
May be bacterial, viral, fungal, rickettsial, mycoplasmal, or parasitic
Bacterial is most common, especially among people with other illnesses
Vaccination for pneumococcal pneumonia for children and older adults

17. Other Infectious Diseases
Mononucleosis (“mono”)
Viral infection characterized by weakness, fatigue, swollen glands, sore throat, and low-grade fever
Chronic fatigue syndrome
Characterized by severe exhaustion, fatigue, aches, and depression
Bacterial meningitis
Infection of the thin membranous coverings of the brain
Higher risk among college students living in residence halls
Immunization available

18. Other Infectious Diseases
Lyme disease
Bacterial infection transmitted by deer ticks
Hantavirus pulmonary syndrome
Extreme pulmonary distress
Transmitted from deer mice to humans
West Nile virus
Transmitted by mosquitoes
Flulike symptoms; may involve encephalitis
Tampon-related toxic shock syndrome
Image source: Centers for Disease Control and Prevention

19. Viral Hepatitis Inflammation of the liver Symptoms Types:
Fever, nausea, abdominal pain, jaundice
Types:
Type A – associated with fecal contamination of food due to poor food handling
Type B – sexual contact, IV drug use, tattooing, piercing
Type C – similar to type B
Type D – difficult to treat; found in type B sufferers; contact with bodily fluids
Type E – water contamination (rare)
Vaccination available for types A and B
Image source: The McGraw-Hill Companies, Inc./Christopher Kerrigan, photographer

20. HIV/AIDS Human immunodeficiency virus (HIV)
Acquired immunodeficiency syndrome (AIDS)
HIV attacks the helper T cells of the immune system
Spread
Direct contact involving the exchange of body fluids (blood, semen, vaginal secretions)
Sharing of hypodermic needles
Infected blood products
Perinatal transmission (mother to fetus or newborn)

21. HIV/AIDS
HIV cannot be transmitted by sweat, saliva, or tears, even though trace amounts of HIV are observed
Women are at higher risk than men of contracting HIV from an infected partner
HIV concentration is higher in semen compared with vaginal secretions

22. Diagnosis of HIV Infection
Enzyme linked immunosorbent assay (ELISA)
Western BLOT test

23. The Course of HIV Infection
Newly infected may experience flu-like symptoms within 1 or 2 months of exposure
Symptoms disappear quickly
Immune system is unable to clear HIV from the body
Asymptomatic stage
Could last for months to over 12 years
Length depends on overall health, age, gender, strain of infection
Immune system worsens
Level of CD4 helper T cells
Opportunistic infections

24. Treatment of HIV Infection
No cure at this time
HAART (highly active antiretroviral therapy) can significantly reduce viral load
Antiviral drugs
Drug resistance
Image source: The McGraw-Hill Companies, Inc./Christopher Kerrigan, photographer

25. Prevention of HIV Infection
Learn the sexual history and HIV status of your partner
Limit the number of sexual partners
Use condoms correctly and consistently
Avoid contact with body fluids
Curtail the use of drugs
Never share hypodermic needles
Refrain from sex with known injectable drug users and other high-risk partners
Get regular tests for STDs
Do not engage in unprotected anal intercourse

26. Number of Lifetime Sexual Partners among Adults (Age 20-59)
Figure 11-5 Number of Lifetime Sexual Partners among Adults Age 20-59

27. Sexually Transmitted Diseases
HIV/AIDS
Chlamydia
Human papillomavirus
Gonorrhea
Herpes simplex
Syphilis
Pubic lice
Vaginal infections
Cystitis and urethritis

28. Prevalent STDs Chlamydia Human papillomavirus (HPV)
Bacterium Chlamydia trachomatis
Urethritis
Left untreated, can cause pelvic inflammatory disease and infertility in women
Human papillomavirus (HPV)
Often asymptomatic
Can cause genital warts, cervical cancer
Vaccine; not curable

29. Prevalent STDs Gonorrhea Herpes simplex Bacterium N. gonorrhoea
Symptoms: painful urination, discharge
Treated with antibiotics; some strains are drug-resistant
Herpes simplex
HSV 1 (oral) and HSV II (genital)
Painful blisterlike sores
Pattern of recurrences
Persistent; treated with antiviral drugs

30. Prevalent STDs Syphilis Pubic lice (“crabs”)
Bacterium Treponema pallidum
Three stages:
Primary stage: Painless sore called a chancre
Secondary stage: General symptoms of illness
Latent stage: May recur many years after initial contact; profound damage to many body systems
Left untreated, can cause death
Pubic lice (“crabs”)
Cause intense itching
Treated with prescription and OTC drugs

31. Prevalent STDs Vaginal infections Cystitis (infection of bladder)
Yeast infection (Candida albicans)
Bacterial vaginosis (BV)
Protozoa Trichomonas vaginalis
Cystitis (infection of bladder)
Urethritis (infection of urethra)
Caused by various pathogens
Treated with antibiotics

32. Chapter Eleven: Preventing Infectious Diseases