1. Infection, Immunity, and Noninfectious Disease

2. Diseases
Processes that affect proper body functioning accompanied by associated signs and symptoms
Noninfectious diseases - caused by genetic abnormalities, environmental factors, or a combination of both
Cystic fibrosis, lead-poisoning, asthma
Infectious diseases - caused by pathogens such as bacteria, viruses, fungi, parasitic worms
Colds, flu, sexually transmitted infections

3. Genetic Diseases
Two types: Inherited diseases (inherit “defective” gene) and diseases caused by errors when gametes are formed
Defective (mutated) genes caused by ionizing radiation, toxic chemicals, drugs
Common inherited diseases in the U.S.
Sickle-cell anemia
Cystic fibrosis
Duchenne muscular dystrophy

4. Noninfectious Diseases Caused by an Interaction of Genes and Environment
Asthma
Narrowed airway passages and difficulty breathing
Attacks can be triggered by air pollution, URIs, smoke, dust
Ulcers
Diabetes mellitus
Migraine headaches
Cardiovascular disease
Cancer

5. Trends in Infectious Disease
Infectious diseases are not significant contributors to death in the U.S. today
Worldwide, infectious diseases are the leading cause of death
Many strains of bacteria have become resistant to antibiotics
With international travel commonplace, transmission of infection is a worldwide concern

6. Chain of Infection
Agent of Infection (Pathogen)
Transmission
Host

7. Pathogens
Bacteria (unicellular organisms with a simple cell structure)
Cause diseases such as strep throat, pneumonia, food infection
Rickettsias (bacterialike organisms that live within host cells)
Cause diseases such as typhus, Rocky Mountain Spotted Fever

8. Pathogens (cont’d) Viruses (hereditary material with a protein coat)
Cause diseases such as cold, flu, mumps, measles, chicken pox, hepatitis, HIV infection
Fungi (cause opportunistic infections)
Cause diseases such as athlete’s foot, yeast infections

9. Ringworm

10. Toenail fungus

11. Pathogens (cont’d)
Protozoans (single-celled organisms with a complex cell structure)
Cause disease such as malaria, “trich” infections
Parasitic worms
Tapeworms, roundworms, flukes
Live in digestive system and cause digestive disorders. Flukes can also inhabit the liver, lungs, or veins.

12. Pathogens (cont’d) Arthropods Lice, fleas, mites, and ticks
Cause infestations of various body parts

13. Transmission of Disease
Noncommunicable
Communicable

14. Noncommunicable Diseases
Caused by: Growth of bacteria that normally inhabit the body
Skin infections
Ingestion of toxins or poisons produced by some bacteria
Food poisoning or food infection
Pathogens that infect people via environment or animal sources

15. Communicable Diseases
Transmitted from person to person by
direct or indirect contact
a common vehicle (food, water, a common drinking glass)
the air
vectors (organisms other than humans, such as mosquitoes)

16. Host Stress can reduce resistance to infection
Exhaustive exercise can lower immune system function
Race and age affect resistance or susceptibility to disease

17. Treating Infections Antibiotics (kill or inhibit growth of bacteria)
Over-the-counter medications can sometimes relieve symptoms
Specific medications have been developed to treat certain viral and protozoan infections, and worm infestations

18. Sexually Transmitted Infections
Spread from person-to-person by intimate contact
Caused by certain viruses, bacteria, yeasts, and protozoans
Infestations caused by certain mites and lice

19. HIV Transmission Sexual contact with infected person
Semen, vaginal secretions, or blood
Tears in skin and mucous membranes
Exposure to infected blood or blood products
Shared needles
Blood transfusions
Placental transfer during fetal development, labor/delivery, and breastfeeding

20. Yeast Infections Candidiasis
Acquired through intercourse or develops in women after taking antibiotics
Itching, burning, irritation, swelling, and white vaginal discharge
Can be treated with OTC antifungal creams
Males may experience irritation, swelling, and a rash or white patches

21. SUMMARY
Noninfectious diseases have hereditary or environmental causes, or a combination of both
Genetic diseases are inherited
Two primary causes of infectious diseases are bacteria and viruses
The human body combats infectious disease with both specific and nonspecific types of immunity

22. SUMMARY (cont’d) The severity of a disease depends on:
the type of organism
its virulence
how it spreads in the body
the chemicals it produces
its ability to combat the defense mechanisms of the body
the body’s reaction to the pathogen

23. SUMMARY (cont’d) Many drugs have been developed to combat infection
Adolescents and young adults are at highest risk for contracting STIs