Chp 15 Worksheet

Question 1

Communicable disease

Answer 1

A disease that can be transmitted from one person to another (e.g., influenza, tuberculosis).

Question 2

Noncommunicable disease. Ex.s?

Answer 2

A disease that cannot be transmitted from one person to another (e.g., acne, diabetes).

Question 3

Contagious disease. Ex.s?

Answer 3

A communicable disease that is easily spread from one person to another (e.g., chickenpox, measles).

Question 4

Examples of communicable diseases.

Answer 4

Influenza, tuberculosis, herpes.

Question 5

Examples of noncommunicable diseases

Answer 5

Acne, diabetes, heart disease.

Question 6

Examples of contagious diseases

Answer 6

Chickenpox, measles, COVID-19.

Question 7

Portal of entry

Answer 7

The site through which a pathogen enters the host (e.g., skin, mucous membranes, respiratory tract).

Question 8

Portal of exit

Answer 8

The site through which a pathogen leaves the host (e.g., respiratory secretions, blood, feces).

Question 9

Parenteral route

Answer 9

The entry of pathogens through breaks in the skin or mucous membranes, such as wounds, insect bites, or needle pricks.

Question 10

Infection

Answer 10

The colonization and multiplication of a pathogen in or on a host.

Question 11

Disease

Answer 11

The damage or impairment of the host’s normal functions as a result of the infection.

Question 12

Symptom

Answer 12

Subjective characteristics of a disease felt only by the patient (e.g., pain, nausea, fatigue).

Question 13

Sign

Answer 13

Objective manifestations of a disease that can be observed or measured by others (e.g., swelling, fever, rash).

Question 14

Resident microbiota

Answer 14

Microorganisms that constantly live on or in the body and are typically harmless or beneficial.

Question 15

Transient microbiota

Answer 15

Microorganisms that temporarily colonize the body but do not establish long-term residence; often includes pathogens.

Question 16

Steps in pathogenesis

Answer 16

1. Exposure/contact, 2. Adhesion, 3. Invasion, 4. Infection.

Question 17

Koch’s Postulate 1

Answer 17

The suspected pathogen must be found in every case of the disease and not in healthy individuals.

Question 18

Koch’s Postulate 2

Answer 18

The suspected pathogen must be isolated and grown in pure culture.

Question 19

Koch’s Postulate 3

Answer 19

The cultured/suspected pathogen must cause the same disease when inoculated into a healthy host.

Question 20

Koch’s Postulate 4

Answer 20

The pathogen must be re-isolated from the inoculated host and be identical to the original pathogen.

Question 21

Purpose of Koch’s Postulates

Answer 21

To establish a causal relationship between a specific pathogen and a specific disease.

Question 22

Limitations of Koch’s Postulates

Answer 22

Some pathogens cannot be grown in pure culture (e.g., viruses, certain bacteria); some diseases are caused by multiple pathogens or factors; ethical concerns prevent the use of human hosts for testing.

Question 23

ID50 (Infectious Dose 50)

Answer 23

The number of pathogen cells or virions required to cause infection in 50% of exposed hosts.

Question 24

LD50 (Lethal Dose 50)

Answer 24

The number of pathogen cells or virions required to kill 50% of exposed hosts.

Question 25

How ID50 and LD50 are determined

Answer 25

Using animal models.

Question 26

Benefits of virulence factors

Answer 26

Help microbes adhere to host cells, invade host tissues, evade the host immune system, and cause damage to the host.

Question 27

Importance of adhesion in infection

Answer 27

Adhesion allows pathogens to attach to host cells, which is the first step in colonization and infection.

Question 28

Hyaluronidase

Answer 28

Breaks down hyaluronic acid in connective tissue, allowing pathogens to spread.

Question 29

Collagenase

Answer 29

Breaks down collagen in connective tissue, facilitating tissue invasion.

Question 30

Exotoxin

Answer 30

Secreted toxins that cause damage to host cells.

Question 31

Cytotoxin

Answer 31

A type of exotoxin that kills host cells.

Question 32

Neurotoxin

Answer 32

A type of exotoxin that disrupts nerve function.

Question 33

Enterotoxin

Answer 33

A type of exotoxin that affects the intestines, causing diarrhea.

Question 34

Endotoxin

Answer 34

Not secreted; part of the outer membrane of Gram-negative bacteria, causing inflammation and fever.

Question 35

Lipopolysaccharide (LPS)

Answer 35

A type of endotoxin that triggers a strong immune response.

Question 36

Steps in AB toxin activity

Answer 36

1. The B subunit binds to host cell receptors. 2. The toxin is internalized by the host cell. 3. The A subunit is released and exerts its toxic effect (e.g., disrupting protein synthesis or cell signaling).

Question 37

Steps in botulinum toxin activity

Answer 37

1. The toxin binds to nerve cells at the neuromuscular junction. 2. It is internalized into the nerve cell. 3. The toxin blocks the release of acetylcholine, preventing muscle contraction and causing paralysis.

Question 38

Five stages of infectious disease

Answer 38

1. Incubation period, 2. Prodromal period, 3. Illness, 4. Decline, 5. Convalescence.

Question 39

Incubation period

Answer 39

Time between infection and the appearance of symptoms.

Question 40

Prodromal period

Answer 40

Early, mild symptoms appear.

Question 41

Illness

Answer 41

Disease is most severe, with clear signs and symptoms.

Question 42

Decline

Answer 42

Symptoms begin to subside as the immune system responds.

Question 43

Convalescence

Answer 43

The body returns to its pre-diseased state.

Question 44

Four ways virulence factors promote infection

Answer 44

1. Adhesion, 2. Invasion, 3. Immune evasion, 4. Toxin production.

Question 45

How capsules act as virulence factors

Answer 45

Capsules protect pathogens from phagocytosis by the host immune system, allowing them to evade detection and destruction.

Question 46

Antigenic variation

Answer 46

The ability of a pathogen to alter its surface proteins, allowing it to evade the host immune system.

Question 47

Antigenic variation in Neisseria

Answer 47

Neisseria (e.g., Neisseria gonorrhoeae) can change the expression of its surface proteins (pili and outer membrane proteins) through genetic recombination, allowing it to evade the immune system.

Question 48

Antigenic drift

Answer 48

Small, gradual changes in viral surface proteins due to mutations.

Question 49

Antigenic shift

Answer 49

Sudden, major changes in viral surface proteins due to reassortment of genetic material between different viral strains.

Question 50

Why influenza viruses are prone to antigenic shift

Answer 50

Influenza viruses have segmented genomes, which allows for the exchange of genetic material between different strains, leading to major changes in surface proteins.

Question 51

Why influenza A is more prone to antigenic shift than influenza B

Answer 51

Influenza A infects a wider range of hosts (including humans, birds, and pigs), increasing the chances of genetic reassortment. Influenza B primarily infects humans and is less prone to shift.

Question 52

Local infection

Answer 52

Infection that is a small area of the body, usually around the portal of entry.

Question 53

Focal infection.

Answer 53

A localized infection spreads to a confined secondary location.

Question 54

Systemic infection.

Answer 54

Infection that affects the entire body.

Question 55

Primary and secondary infections.

Answer 55

One pathogen infects first and causes an infection which makes the individual more susceptible to infection by another subsequent pathogen.

Question 56

Are all infections communicable?

Answer 56

No; sometimes humans are a 'dead end' host.