Infectious Processes Patho

Question 1

Chain of Transmission

Answer 1

Infectious Agent -> Reservoir -> Portal of Exit -> Mode of Transmission -> Portal of Entry -> Host
- Chain can be broken at any point

Question 2

Agent/Pathogen/Microbe

Answer 2

Disease-causing organism (infectious)

Question 3

Reservoir

Answer 3

• Place where pathogen lives and reproduces (human)

- Destroy: mosquito eradication, garbage disposal, sewage treatment

Question 4

Portal of Exit

Answer 4

• How organism gets out of reservoir

- Block: masks, gloves, isolation, condoms

Question 5

Mode of Transmission

Answer 5

• How organism is spread (surfaces, fluids, vectors)

- Block: sterile technique, hand washing, body substance isolation

Question 6

Portal of Entry

Answer 6

• How agent gets into host

- Block: masks, gloves, condom use

Question 7

Host

Answer 7

• Individual at risk for contracting organism

- Reduce susceptibility: vaccination, optimal rest and nutrition

Question 8

Epidemiology

Answer 8

Host -> vector -> agent and environment

Question 9

3 types of relationship btw host and pathogen

Answer 9

1. Symbiosis
2. Mutualism
3. Commensalism

Question 10

Symbiosis

Answer 10

Benefit to human and no harm to microorganism

Question 11

Mutualism

Answer 11

Benefit human and microorganism

Question 12

Commensalism

Answer 12

Benefit to microorganism and no harm to human

Question 13

Pathogenicity

Answer 13

Benefits organism and harms human

Question 14

Immunogenicity

Answer 14

Ability of microbe to induce immune response

Question 15

Host Characteristics

Answer 15

• Physical and Mechanical Barriers: epithelial cells (protective), mucus membranes, coughing/sneezing/peeing/pooping, sweat/saliva/tears
• Risk Factors: age, nutritional status, chronic illness, immunosuppression, chronic stress
• Immunization: directly or by herd immunity

Question 16

Host Defenses

Answer 16

• Physical & Mechanical Barriers
• Innate inflammatory response
• Adaptive immunity response

Question 17

2 classifications of microbes

Answer 17

• Normal microbial flora: beneficial

- Others: pathogenic/disease-causing

Question 18

Characteristics of pathogenic microbes

Answer 18

• Adherence (stickiness, makes it harder for our defenses to attack)
• Invasive (how microbes get access into host and survive)
• Endotoxins and Exotoxins
• Bacterial enzymes (degrade tissue or dissolve blood cells)
• Antiphagocytic factors (outside coating to disguise and get rid of)
• Endospores (internal store of resting state is resistant to heat and chemicals)
• Mobility (flagellum to move toward nutrients or away from repellants)
• Antimicrobial resistance (mutation that allows microbe to survive in presence of antibiotic)

Question 19

Bacteria Characteristics

Answer 19

• Single celled, rigid wall, no internal organelles
• Shapes: cocci (spherical), bacilli (rod or comma), spiral (twist)
• Gram stain tells us about cell wall components: positive (dark blue), negative (pink), acid fast (resist stain)
• O2 requirements: aerobic or anaerobic

Question 20

Fungi Characteristics

Answer 20

• Eukaryotic, contains organelles, form complex structures, thick rigid cell wall
• Many are part of normal flora (become a problem when defense mechanisms are compromised)
• Infections caused by fungi = mycoses, mycotic infections
• Locations: superficial and cutaneous, subcutaneous, systemic

Question 21

Parasite Characteristics

Answer 21

• Establish themselves with another organism and benefit from the other
• Types: protozoa (single-celled), helminthes (roundworms and flatworms), arthropods (invertebrate animals with jointed appendages)
• Sites: skin and GI tract

Question 22

Virus Characteristics

Answer 22

• Most common afflictions
• Simple microorganisms: no metabolism, incapable of independent reproduction
• Need to infect a permissive host to replicate, turn cells into replication machine
• Can bypass many defense mechanisms because they develop intracellularly (protected)

Question 23

Incubation

Answer 23

• Clinical Infectious Disease Stage 1
• period from initial exposure to onset of first symptoms
• still infectious

Question 24

Prodromal

Answer 24

• Clinical infectious disease stage 2

- occurrence of initial symptoms (mild)

Question 25

Illness

Answer 25

• Clinical infectious disease stage 3
• pathogen is multiplying rapidly
• immune and inflammatory responses are triggered
• development of symptoms specific to pathogen

Question 26

Convalescence

Answer 26

• Clinical infectious disease stage 4
• immune and inflammatory systems have successfully removed agent and symptoms decline
• latency phase with resolution until reactivation (fatal)

Question 27

Acute illness

Answer 27

severe manifestation but short course

Question 28

Chronic illness

Answer 28

lasts months to years

Question 29

Subclinical illness

Answer 29

patient functions normally even though disease process is well-established

Question 30

Exacerbation

Answer 30

sudden increase in severity

Question 31

Remission

Answer 31

decline in severity of the illness

Question 32

Assessment of Clinical Manifestations of Illness

Answer 32

• Depends on characteristics of pathogen and host
• Majority of signs and symptoms are from inflammation
• Nonspecific: fatigue, malaise, weakness, general aching, loss of appetite
• Hallmark is fever except in elder adults
• ADPIE: assess history, physical, labs, imaging and intervene to prevent infection, eliminate microorganisms, provide comfort care