In Vivo models

Question 1

Why would in vivo models be used to study microbial caused disease?

Answer 1

Can allow us to study the mechanisms that actually cause disease, as well as the interaction between the microbe and the immune system, view the disease from the host perspective, can allow us to find new treatments

Question 2

What are the ideal characteristics for an in vivo?

Answer 2

The causal agent, route of entry and spread in the body should be identical or at least similar to the situation in humans
The tissue involvement, severity and course and duration of disease should be measurable, predictable and amenable to analysis

Question 3

What are the the three R’s of using animal models in scientific labs?

Answer 3

Replacement
Reduction
Refinement

Question 4

What is the refinement principal in scientific animal testing?

Answer 4

The experiment should be refined to minimize animal pain and suffering

Question 5

What is the replacement principal in scientific animal testing?

Answer 5

The idea to replace organisms with those not covered under the protection act and reduce animal use in general wherever possible

Question 6

What is the reduction principal in scientific animal testing?

Answer 6

Use just enough organisms as is required to get useful data

Question 7

What are the two ways in which a microbe can cause disease?

Answer 7

It can release toxins or the immune system can react to the pathogen in a way the causes damage

Question 8

What can lead to an opportunistic pathogen causing disease?

Answer 8

A genetic defect
Exposure to antimicrobial compounds
Exposure to immunosuppressive drugs
Exposure to ionizing
After infection with an immunosuppressive drug

Question 9

What are the advantages of using C. Elegans as an animal model?

Answer 9

Has an innate immune system
Feeds on non-pathogenic microbes, allowing pathogenic bacteria to be introduced in food
Genome is sequenced and it is easy to knock out specific genes
Fast, easy and cheap to grow

Question 10

What are the disadvantages of using c. elegans as an animal model?

Answer 10

It does not have a circulatory or respiratory systems

Lacks an adaptive immune system

Question 11

How can C. Elegans be used to study microbial disease?

Answer 11

It can be used to identify host and disease factors by knocking out genes on the host or the microbe

Question 12

What are the advantages of using drosophila as an animal model?

Answer 12

The genome is sequenced
Contains well studied innate immune system
Short generation time, easy to store and keep

Question 13

What are the disadvantages of using drosophila as an animal model?

Answer 13

Many virulence factors which are essential for disease in mice are not essential in flies

Question 14

How is drosophila used to study microbial disease?

Answer 14

The thoracic segment is pierced with an infected needle (some are pierced with an sterile needle as control)
Antibiotics can be used by mixing it with the sugar water used on the filter paper for feeding

Question 15

What are the advantages of using zebrafish as an animal model?

Answer 15

Has a translucent embryo, adaptive and innate immune system, genes can be knocked in and out, there are lines of zebrafish with differently tagged cells, inexpensive once labs are established, can be injected with microbes at different

Question 16

What are the disadvantages of using zebrafish as an animal model?

Answer 16

It has a different body temperature to humans and often human pathogens have genes that are only activated when they are in the host

Question 17

What are the advantages of using galleria mellonella (wax moth)as an animal model?

Answer 17

Has an innate immune system, changes in pigmentation allows areas of necrosis to be easily identified, can survive at 37 degrees celcius, easy to infect and administer antibiotics, large enough to handle

Question 18

How are zebrafish used to study microbes?

Answer 18

Microbes are injected at different sites in the fish

Question 19

What are the disadvantages of using wax moths as a model organism?

Answer 19

They do not have an adaptive immune response and have not yet gained critical research mass

Question 20

How are wax moths used to study microbes?

Answer 20

They are injected with microbes, pigmentation can then be used to visualise disease progress

Question 21

What are the advantages of using mice as a model organism?

Answer 21

They are highly complex, containing an innate and adaptive immune response, they have an accelerated life cycle, many different lines are available, they are often genetically similar to each other, can be humanised to express human receptors

Question 22

What are the disadvantages of using mice as a model organism?

Answer 22

Selecting the correct strain for your research is critical, some pathogens are species limited and will not cause disease in mice but will in humans

Question 23

How are microbes studied in mice?

Answer 23

A mouse analogue pathogen is used or the mouse can be humanised

Question 24

How can biophotonic imaging be used in research?

Answer 24

It is a highly sensitive an non-toxic technique where certain cells or microbes are engineered to produce light which will be detected by a photosensitive camers this allows for dramatic reduction in the number of animals required for studies

Question 25

What are the advantages of using Macaque as a model organism?

Answer 25

Closer relative innate and adaptive immunity to humans

Question 26

What are the disadvantages of using a Macaque as a model organism?

Answer 26

It is an emotive species which is expensive, difficult to source and highly regulated