Module 2 Chapter 10

Question 1

Host

Answer 1

Organism capable of sustaining nutritional and physical requirements of another organism.

Question 2

Infectious Disease

Answer 2

The host sustains injury at the hands of an invading organism.

Question 3

colonization

Answer 3

Presence of microorganisms within a host. No harm done, yet. Can lead to infectious processes if left unchecked and the organism is capable of disease.

Question 4

Microflora

Answer 4

Normal microorganisms that harmlessly inhabit the host.

Question 5

Virulence

Answer 5

The ability of a microorganism or pathogen to cause a disease. Disease-producing potential.

Question 6

Pathogens

Answer 6

Disease causing microorganisms.

Question 7

Saprophytes

Answer 7

Organisms that get nutrients from dead or decaying matter. Harmless.

Question 8

Mutualism

Answer 8

Interaction where both the host and the microorganism derive benefit from the relationship.

Question 9

Commensalism

Answer 9

The colonizing microorganism acquire a benefit from the relationship, does not harm the host.

Question 10

Parasitic Relationship

Answer 10

Only the microorganisms benefit from the relationship. The host either benefits nothing or is harmed from the relationship.

Question 11

Triad of infectious disease

Answer 11

Interactions between:
1. A susceptible host
2. The environment
3. Invading agent

Question 12

Prions
1. How does infection present?
2. How does infection spread?
3. Example?

Answer 12

Prions are proteins that are able to self-propagate.
1. Typically slowly results in neurological degradation. Ataxia, dementia, death.
2. The prions are self-propagating. They spread via consumption of infected meat usually.
3. Kuru, mad cow disease

Question 13

Viruses
1. Limitations of spread, why?
2. Capsid
3. Speed of action
4. Examples

Answer 13

Smallest intracellular pathogens.
1. Must reproduce inside the host. They use the host cells structure to replicate.
2. Have a DNA or RNA coat called a capsid.
3. Can cause immediate effect or lay dormant for extended periods.
4. Flu, HIV

Question 14

Bacteria
1. Cell structure
2. Gram (+) vs (-)
3. Movement

Answer 14

Small unicellular organisms that lack cellular structures. Have a cell wall for protection.
2. Gram (+) - cell wall is composed of peptidoglycan. Gram (-) - cell wall composed of lipopolysaccharide.
3. Can propel itself in some cases through the use of flagella.

Question 15

Contrast viruses and bacteria

Answer 15

Viruses - smaller. No cell structure. Protein or DNA coat.
Bacteria - Unicellular (prokaryotes), do not require a host to replicate, cell wall Gram (+) and Gram (-). Have specific survivable parameters.

Question 16

Rickettsiaceae

Answer 16

Combination or viral and bacterial characteristics. DNA or RNA. Cell wall. Cellular division. Obligate intracellular pathogen. Infect arthropods where they cause no symptoms. The arthropods in turn infect mammals through bites. Can cause Rocky Mountain Spotted fever, Lyme disease.

Question 17

Chlamydiaceae

Answer 17

Similar to the Rickettsiaceae. Viral properties - obligate intracellular pathogens. Bacteria - rigid cell wall, reproduce asexually by cellular division, contain DNA and RNA.

Uniquely, they spread via close contact.

Question 18

Fungi
1. Type of organism
2. When do they become infectious?
3. Categories - explain the differences
4. Restrictions
5. Examples

Answer 18

1. Fungi are free living, eukaryotic (nucleus, organelles, cell membrane), saprophytes.
2. Very few fungi cause risk for infection. The ones that do are typically limited to the skin.
3. Of the fungi that cause infections, there are two categories:
   a. Yeast - unicellular, reproduce by budding.
   b. Molds - multicellular.
4. Fungi growth is restricted by environmental factors like temperature. This prevents many of them from being able to grow on and in the body. It restricts others to specific areas of the body.
5. Candida, aspergillosis, dermatophytes (ring worm, jock itch, athletes foot)

Question 19

Parasites
1. Protozoa
2. Helminths
3. Arthropods/Ectoparasites

Answer 19

Any organism that derives benefits from a host organism.
1. Protozoa - unicellular animals. Most are saprophytes. Some are pathogens - malaria, dysentery, giardiasis.
2. Worms - nematodes (roundworms), cestodes (tapeworms), flukes. Enter the body via ingestion or penetration. Reproduce and feed off the host.
3. Vectors of infectious disease - spread the disease through bites. Mosquitos, ticks, lice, mites. Ectoparasites - parasites that live on the surface of the skin - scabies (mites), chiggers, lice, fleas.

Question 20

Epidemiology

Answer 20

The study of patterns and determinants of health within a population with the goal of controlling the disease.

Question 21

Incidence

Answer 21

Th e number of new cases of a disease affecting a certain population within a certain time period.

Question 22

Prevalence

Answer 22

Number of active cases of a disease in a population.

Question 23

Endemic Disease

Answer 23

A stable incidence/prevalence of disease within a specific geographical location

Question 24

Epidemic

Answer 24

an abrupt and unexpected increase in incidence/prevalence over the endemic level.

Question 25

Pandemic

Answer 25

Spread of a disease beyond continental boundaries.

Question 26

Nosocomial Infection

Answer 26

“Hospital acquired” - a disease that is contracted while in the hospital. Occurs after the first 48 hours.

Question 27

Phases of a disease course

Answer 27

1. Incubation
2. Prodromal
3. Acute
4. Convalescent
5. Resolution

Question 28

Incubation stage

Answer 28

The first phase of the disease course. Characterized by pathogen replication within the host cells without recognizable symptoms. Can be short or prolonged.

Question 29

Prodromal stage

Answer 29

Initial appearance of non-specific symptoms (low grade fever, malaise, myalgia, headache, fatigue). At this stage the disease can be transmitted to others.

Question 30

Acute stage

Answer 30

Disease specific symptoms become evident. The host feels the full force of the disease. The pathogen is rapidly proliferating.

Question 31

Convalescent Period

Answer 31

Containment of the pathogen, progressive elimination of the pathogen, repair of damage done, resolution of symptoms.

Question 32

Antimicrobial

Answer 32

fights against microorganisms

Question 33

Antibacterial
1. Where did most antibiotics come from?
2. Bactericidal Vs. Bacteriostatic]

Answer 33

AKA antibiotics
1. Most antibiotics are produced by bacteria and fungi as a byproduct of metabolism. Humans captured this information and have directed it against identified pathogens.
2. Bactericidal - eliminate bacteria. Lethal.
Bacteriostatic - Slow the spread of bacteria. Inhibit bacteria growth. When the bacteriostatic stimuli is removed the bacteria can start growing again.

Question 34

Antiviral Agents

Answer 34

Newer therapies. Cause host toxicity - this is where the antiviral medications cause toxic affects to the host organism. This is because many viruses utilizes the hosts own cells to proliferate.

Question 35

Antifungal Agents

Answer 35

Target the cytoplasmic membrane. Unlike human cell membranes which are reinforced with cholesterol, fungi cell membranes are reinforced with sterol ergosterol. This difference is utilized to target fungi cells and leave the host cells be.

Polyene binds to ergosterol which makes holes in the cell membrane leading to cell lysis.

Imidazole inhibits ergosterol synthesis.