Introduction to Infectious Disease Lecture Review

Question 1

a disorder caused by pathogenic organisms.

Answer 1

infectious disease

Question 2

the time between catching an infection and symptoms appearing

Answer 2

incubation period

Question 3

a microorganism that produces disease.

Answer 3

Pathogen

Question 4

True/False, ALL MICROORGANISMS ARE PATHOGENS!!

Answer 4

False. Some are part of our normal flora

Question 5

the ability of an organism to produce disease

Answer 5

Virulence

Question 6

Any person,animal, plant, soil or substance in which an infectious agent normally lives and multiplies

Answer 6

Reservoir

Question 7

diseasesconsidered to be of great public health importance

Answer 7

Reportable diseases

Question 8

disease that can be transmitted from animals to humans

Answer 8

Zoonosis

Question 9

List the 4 major categories of pathogenic organisms that cause infectious disease

Answer 9

Bacteria
Fungi
Viruses
Parasites

Question 10

Prokaryotic organism, typically a few mm in length, ranging fromspheres to rods and spirals.

Answer 10

Bacteria

Question 11

How are bacteria named?

Answer 11

Binomial with genus and species.
Genus is suggestive of morphology, discoverer or other characteristics
species is suggestive of metabolic features, biochemical characteristics or disease

Question 12

What is the “Genus” of a bacteria

Answer 12

The first part of the name, always always capitalized and underlined; Genus is suggestive of morphology, discoverer or other characteristics

Question 13

What is the “species” of a bacteria

Answer 13

the second part of the name, always capitalized and underlined; species is suggestive of metabolic features, biochemical characteristics or disease

Question 14

Staphylococcus epidermidis is a type of bacteria. Which part of this name represents the Genus?

Answer 14

Staphylococcus

Question 15

Staphylococcus epidermidis is a type of bacteria. Which part of this name represents the species?

Answer 15

epidermidis

Question 16

What is the purpose of a bacterial cell wall?

Answer 16

Determine shape of a bacterium
Provide strong structural support

Question 17

What is gram staining used for?

Answer 17

Differences in structure determine Gram staining.
Gram staining helps identify the bacterium as either gram positive or gram negative.

Question 18

A gram positive organism will stain

Answer 18

purple

Question 19

A gram negative bacteria will stain

Answer 19

pink

Question 20

A bacteria has “Bacillus” in its name. What shape will this organism be?

Answer 20

rod shaped

Question 21

A bacteria has “coccus” in its name. What shape will this organism be?

Answer 21

spherical/round

Question 22

A bacteria is seen under the microscope as multiple round cells in grape-like clusters. Would you expect this to be a Streptococcus sp. or a Staphylococcus sp.?

Answer 22

Staphylococcus sp.

Question 23

A bacteria is seen under the microscope as multiple round cells in long chains. Would you expect this to be a Streptococcus sp. or a Staphylococcus sp.?

Answer 23

Streptococcus sp.

Question 24

a large group ofeukaryoticorganisms that includes microorganisms such asyeastsandmolds, as well as the more familiar mushrooms.

Answer 24

Fungi

Question 25

Fungi can be divided into two groups:

Answer 25

Macroscopic fungi (mushrooms, puffballs, gill fungi) Microscopic fungi (molds, yeasts)

Question 26

Cells of microscopic fungi exist in two basic morphological types:

Answer 26

Yeasts Hyphae

Question 27

Ex of disease caused by microscopic fungi:

Answer 27

Yeasts--ear infections, caused by Malassezia sp. Hyphae-ringworm, caused by Microsporum or Trichophyton sp.

Question 28

Describe what a yeast would look like under the microscope

Answer 28

purple stain, larger than a bacteria, "snowman" or "packing peanut" appearance

Question 29

a small infectious agent that replicates only inside the living cells of other organisms

Answer 29

virus

Question 30

The basic structure of a virus consists of

Answer 30

capsid, nucleic acid, +/- an envelope.

Question 31

True or False. The nucleic acid of a virus consists of either DNA or RNA, but never both.

Answer 31

True

Question 32

non-mutual relationship between species, where one species, the parasite, benefits at the expense of the other, the host.

Answer 32

Parasitism

Question 33

The three main types of organisms causing parasitic infections

Answer 33

protozoa, helminths, and ectoparasites

Question 34

parasites that are single cells

Answer 34

Protozoa

Question 35

Protozoal life stages include:

Answer 35

Trophozoite: motile, feeding stage, requires ample food and moisture to remain active Cyst: dormant, resting stage for when conditions are unfavorable for feeding

Question 36

How do protozoa move?

Answer 36

Pseudopods: blunt, branched, or long and pointed; produces amoeboid motion Flagella: long, sheathed ,cylinders Cilia: similar to flagella, but shorter and more numerous

Question 37

2 major groups of parasitic helminthes are

Answer 37

Platyhelminthes and Aschelminthes

Question 38

Flatworms have a very thin, often segmented body are classified as:

Answer 38

Platyhelminthes (cestodes and flukes)

Question 39

Nematodes have elongated, cylindrical, unsegmented body and are classified as

Answer 39

Aschelminthes

Question 40

Examples of nematodes

Answer 40

Roundworms Whipworms Hookworms Pinworms

Question 41

animals harbor an infectious agent without displaying clinical signs and may transmit the infectious agent to other animals.

Answer 41

carrier animal (or reservoir animal)

Question 42

What is "horizontal" disease transmission?

Answer 42

Transmission of disease among unrelated animals

Question 43

What is "vertical" disease transmision?

Answer 43

Transmission of disease from a parent to an offspring in the period prior to birth or immediately after birth

Question 44

What is a "vector"

Answer 44

an organism, typically a biting insect or tick, that transmits a disease or parasite from one animal or plant to another.

Question 45

What is a "fomite"?

Answer 45

inanimate object that can harbor a disease causing organism

Question 46

Examples of horizontal transmission:

Answer 46

Direct contact Airborne Droplet Indirect (fomites) Vector-borne Fecal-oral

Question 47

What is transmission by direct contact?

Answer 47

Requires physical contact between infected and susceptible animals and the physical transfer of microorganisms Examples: Licking, Rubbing, Biting, Coitus

Question 48

True/False. Diseases spread by direct contact cannot survive long away from host

Answer 48

True!

Question 49

True/False. Organisms spread via airborne transmission must be capable of surviving for long periods of time outside the body and must be resistant to drying

Answer 49

True

Question 50

What is transmission by droplet contact?

Answer 50

Droplets containing microorganisms can be generated when an infected animal coughs, sneezes, or barks Droplets are too large to be airborne for long periods of time, and quickly settle out of air.

Question 51

What is transmission by indirect contact?

Answer 51

A susceptible animal is infected from contact with a contaminated surface or utensil (a fomite). Some organisms are capable of surviving on surfaces for an extended period of time, serving as a source of transmission.

Question 52

What is a biological vs a mechanical vector?

Answer 52

Biological vectors, such as mosquitoes and ticks may carry pathogens that can multiply within their bodies and be delivered to new hosts, usually by biting. Mechanical vectors, such as flies can pick up infectious agents on the outside of their bodies and transmit them through physical contact.

Question 53

What is fecal-oral transmission?

Answer 53

Inside the digestive system, the microorganisms multiply and are shed from the body in feces. Microorganisms enter the body through ingestion.

Question 54

How can two animals come into contact with a disease in their environment and only one of them get sick?

Answer 54

Host Factors (Age, Nutritional Status, Health Status, Immunization status, Stress) Environmental Factors (Temperature, Humidity, Sanitation) Agent Factors (Virulence, Mode of Transmission, Amount of Exposure)

Question 55

What characteristics of Infectious Disease that Influence Potential for Introduction?

Answer 55

1. its's persistence in the Environment 2. Whether it's immediately Infectious or needs time to develop to infectious stage 3. The organisms life cycle-- does it have an Indirect life cycle, requiring development in vector/another host?