Introduction to Infection Flashcards
(36 cards)
1
Q
Why do we need to know the cause of infection?
A
- need to be able to measure infection with the correct tests
- need to give the correct treatment
- need to know the appropriate biosecurity measures to stop it spreading
- need to know what vaccines will be effective
- need to understand the disease progression
2
Q
What is the definition of infection?
A
- colonisation of an individual by an infectious agent
3
Q
What is the definition of a disease?
A
- when normal bodily functions are impaired, reducing performance and leading to clinical signs
4
Q
What is a carrier?
A
- any animal that can spread the pathogen
5
Q
What is aetiology?
A
- the cause, or causes of a disease or condition
- not all disease have a single aetiology some have multiple
6
Q
What is an incubation period?
A
- the time period between infection and when clinical signs are observed
can be a few days - months/years
7
Q
What is an infectious period?
A
- the time interval during which a host is infectious
8
Q
Why is incubation period important?
A
- helps with diagnosis
- helps with treatment
- important for biosecurity
9
Q
What are 4 ways we can categorise infectious agents?
A
- By size
- by location
- by evolutionary classification
- by transmission
10
Q
Size - what are microparasites?
A
- parasitic organisms you can see by the eye
- multicellular
- fleas, mites, ticks, worms (nematode, tapeworm, trematode)
11
Q
Microorganism lifestyles can be what?
A
- parasitic
- opportunistic
- mutualism/commensal
- symbiosis
- saprophyte
12
Q
Describe a parasitic lifestyle
A
- can cause a disease by themselves
- can infect healthy individuals
- commonly require a host to reproduce
13
Q
Describe a opportunistic lifestyle
A
- infection caused by an infectious agent due to an opportunity that has occurred allowing the infection to occur
- weakened immune system
- removal of a microbiome
- breached barrier
- current infection
14
Q
Describe a commensal/mutualism lifecycle
A
- a relationship where one or both benefit, but without detriment affect to either party
- commensals can become opportunistic
15
Q
Describe a symbiosis lifecycle
A
- a relationship where both organism benefit and are dependent on each other
- e.g., microbiome in cattle/ horse GI tract
16
Q
Describe a saprophyte lifecycle
A
- microorganism that lives on dead or decaying organic matter
- impact of saprophytic bacteria on post-mortems of animals
17
Q
How do we classify infectious agents by location?
A
- extracellular or intracellular
- localised or disseminated
18
Q
What can location be split into for parasitology?
A
- endoparasites (helminths, protozoans)
- ectoparasites (fleas, ticks, lice, mites, monogeneans)
19
Q
where are most ectoparasites found?
A
- skin
20
Q
where are most helminths found?
A
- alimentary
- cardiorespiratory
21
Q
where are most protozoan parasites found?
A
- blood-borne
22
Q
How can pathogens be divided based on evolution?
A
- organisms are either prokaryotic or eukaryote
23
Q
Why are viruses an exception to evolution categories?
A
- viruses are neither prokaryotic or eukaryote
- they don’t fully meet definition of an organism
- no virus can replicate independently
24
Q
What are prions and why don’t they fit into the evolution category?
A
- they don’t fit into prokaryote or eukaryote
- just proteins but transmissible
- can misfold host prion proteins
- cause Bovine Spongiform Encephalopathy
25
What is a Eukaryotic cell?
- eukaryotic cells have a nucleus and other organelles that are surrounded by a membrane
- they are found in multicellular organisms
26
What are the components of a eukaryote?
- plasma membrane
- cilia
- cytoplasm
- cytoskeleton
- centriole
- lysosomes
- peroxisome
- mitochondria
- ER
- Golgi apparatus
- nucleolus
- nucleus
- nuclear envelope
- ribosomes
27
What is a prokaryotic cell?
- prokaryotic cells from single-celled organisms such as bacteria
- they do a membrane bound nucleus or organelles
28
What are the components of a prokaryote?
- nucleoid area containing DNA
- capsule
- plasma membrane
- cytoplasm
- flagellum
- plasmid - small circles of DNA
- ribosomes
29
Why does it matter whether an infectious agent is prokaryotic or eukaryotic?
- immune recognition varies between the two
- treatments are designed to interact with unique molecules in the pathogen
- different structures are found in prokaryotic/eukaryotic organisms
30
What are Toll-like receptors?
- they are receptors in key immune cells that can recognise specific pathogen-associated molecular patterns (PAMPs)
31
What routes do pathogen have to transmit?
- ingestion
- aerial transmission
- direct contact
- indirect contact - e.g., fomites
- inoculation - vector bone bites
- iatrogenic transmission - creates by doctor
- across placenta
32
What can transmission be subdivided into what?
- Horizontal
- Vertical
- transmission can be both
33
What is horizontal transmission?
- transmitted from any individual to another of the same generation
34
what is vertical transmission?
- transmission from one generation to the next by infection of embryo/foetus/newborn by parent
35
What is a direct lifecycle?
- a lifecycle in which a parasite is transmitted directly from one host to the next without an intermediate host or vector
36
What is an indirect lifecycle?
- where one or more intermediate hosts are required
