Chapter 3: Infectious Disease

Question 1

Pathogen

Answer 1

Infectious disease-causing agent

Question 2

Types of Pathogens?

Answer 2

o	Bacteria
o	Viruses
o	Fungi
o	Protozoa
o	Parasitic worms

Question 3

Transmission of Pathogens?

Answer 3

o People (direct/indirect/airborne)
o Food
o Water
o Animals/Insects

Question 4

1st line of defense

Answer 4

o	Intact skin
o	Cilia
o	Mucous coat
o	Elevated body temp.
o	Cough, tears, saliva

Question 5

2nd line of defense

Answer 5

o Cell-mediated immunity (macrophages and T-cells)
o Humoral Immunity (B-cells to antibodies)
-these immune cells recognize pathogens since they have antigens on their surface

Question 6

Chain of Infection?

Answer 6

• Pathogen (virus)
• Human Reservoir (first infected)
• Portal of exit (pathogen exits)
• Transmission (enters another human)
• Portal of entry (human #2 infected)
• Establishment of disease in new host

Question 7

Acquiring Immunity?

Answer 7

o 1. Fetus gets antibodies from it’s mother
o 2. Injection of antibodies (cannot fight disease in future)
o 3. Exposed to pathogen, then develop immunity
o 4. Vaccinated (can fight it again)

Question 8

Infectious Diseases in Canada?

Answer 8

• Colds
• Influenza
• Hepatitis
• Meningitis
• Reproductive and Urinary infections
• Sexually transmitted Infections

Question 9

Cold

Answer 9

• 200 distinct types
• spread by coughs, sneezes
• best cure your immune system

Question 10

Influenza

Answer 10

• More severe symptoms (aches, chills, dry cough)

- Annual vaccine usually available

Question 11

Hepatitis

Answer 11

• Viruses (A-G) cause inflammation of liver
• Symptoms: high fever, headaches, fatigue, stiff/aching
• Hep A/E transmitted by contaminated water
• Hep B/C/D transmitted through sexual contact

Question 12

Meningitis

Answer 12

• Infection of fluid and membranes surrounding brain and spinal cord
• Symptoms: fever, drowsiness, confusion, severe headache

Question 13

Reproductive and Urinary tract infections?

Answer 13

• Vaginal Infections (itching, burning)
• Penile Infections (redness, irritation)
• Urinary Tract (pain while urinating)

Question 14

Protection at individual level?

Answer 14

o	Wash hands often with hot water and soap
o	Adequate sleep and exercise
o	Eat a balanced diet
o	Don’t share food/drinks
o	Avoiding rubbing your eyes and touching your mouth
o	Don’t bite your nails
o	Don’t smoke
o	Practice Safe Sex

Question 15

Protection at community level?

Answer 15

o Pasteurization: heat-treating of fluids such as milk, orange juice, and beer to kill microorganisms
o Vaccination: used to eradicate common infectious disease
o Proper use of Antibiotics: Using them responsibly, micro-organisms can build up a tolerance towards certain antibiotics meaning that they may not be as useful as before
o Nutrition
o Adequate housing

Question 16

Cell-mediated immunity

Answer 16

• Consists of macrophages and T-cells
• -Fight pathogens
• -Thousands of T-cells work together to kill pathogens
• Macrophages
• • surround and digest foreign matter
• -aid in humoral immunity by engulfing antibody-bound pathogens

Question 17

Humoral Immunity

Answer 17

• Antibodies:
• -proteins that sick to specific antigens on pathogens
• -made by B-cells
• -Coat pathogens and make them clump together so new pathogens:
• –cannot infect new cells
• –more effectively eaten by macrophages

Question 18

B-Cells

Answer 18

White blood cells that produce antibodies and aid in immunological memory

Question 19

T-Cells

Answer 19

White blood cells specialized to assist B cells (helper T) and others directly kills infected cells (killer T)

Question 20

Antibody

Answer 20

Specialized Y-shaped protein that tags antigens for destruction

Question 21

Anti-gen

Answer 21

Marker on pathogen that stimulates an immune response