Lecture 6A & B Flashcards
1
Q
What is a Passive vector
A
agent does not
replicate within the vector.
2
Q
What is active vector
A
agent does replicate
within the vector.
3
Q
What are the route of transmission
A
- Vector-borne transmission
- Airborne transmission
- Faeco-oral transmission
- Direct transmission
- Indirect / fomite transmission
- Common vehicle transmission
- Iatrogenic transmission
- Zoonotic transmission
4
Q
What are the types of transmission
A
Horizontal and Vertical transmission
5
Q
What is horizontal transmission
A
- Vector-borne transmission
- Airborne transmission
- Faeco-oral transmission
- Direct transmission
- Indirect / fomite transmission
- Common vehicle transmission
- Iatrogenic transmission
- Zoonotic transmission
6
Q
What is Vertical transmission
A
Mother to offspring transmission in utero
or in ovo (early post-partum period)
Transmission across placenta, in birth
canal, in colostrum/milk
7
Q
What can vertical transmission do
A
Cause embryonic death, mummification,
resorption (time of gestation) or congenital
defects
8
Q
What is Disease control
strategy based on
A
Vaccination
Movement restrictions
Stamping out
Quarantine
9
Q
When does the disease happen
A
when a non-vector animal(reservoir animal) infect a vector animal
10
Q
What are some passive vector disease
A
• Equine infectious anaemia: biting flies
• Myxomatosis: fleas, mites, mosquitos
• HIV/AIDS: injecting drug use
(not primary route of transmission)
11
Q
How to prevent passive transmission
A
Prevent contamination of vector Prevent access of vector to susceptible new host Immunological protection of susceptible new host
12
Q
What disease is Equine infectious anaemia
A
Retrovirus disease
13
Q
How is Equine infectious anaemia transmitted
A
Transmitted by biting flies:
tabanid flies and stable flies
(stomoxys spp.).
14
Q
How does Equine infectious anaemia spread
A
Iatrogenic spread (non-sterile needles and syringes) Blood containing EIAV is transmitted when fly bites next host
15
Q
What does Equine infectious anaemia do
A
White cells attacking red blood cells Sub-acute EIA: continued moderate fever followed by recovery. Some recurrent episodes of fever/disease Chronic EIA: mild illness, fever, anaemia, oedema
Life-long persistent infection
16
Q
How to control Equine infectious anaemia
A
Prevent insect bites
Remove life-long carriers
(Coggins test)
Use sterile needles and syringes
17
Q
What is myxomatosis
A
Poxvirus disease of rabbits: Causes benign fibromas in wild rabbits in Americas Severe generalised disease in European rabbits
18
Q
What are the vectors for myxoma virus
A
Mosquito, fleas
19
Q
What is Arboviruses
A
Arthropod borne viruses
replicate in their haematophagous arthropod hosts and
transmitted to vertebrate host by biting
20
Q
What does haematophagous mean
A
blood sucking
21
Q
What are the usual virus reservoir for mosquito
A
birds
22
Q
What is ornithophilic mosquito?
A
bird attracted mosquito
23
Q
What is enzootic cycle
A
also enzootic or sylvatic transmission cycle, is a portion of the natural transmission cycle of a pathogen
24
Q
What is epizootic cycle
A
An epidemic outbreak of disease in an animal population, often with the implication that it may extend to humans
25
What is the pathogenesis of genus flavivirus
```
Bite from infected arthropod
Local virus replication
Viraemia
Dissemination to target organs
(endothelium, liver, foetus, CNS)
Family Flaviviridae
Mature virions quite labile:
sensitive to heat, detergents, common disinfectants
```
26
Where did west nile virus start?
USA bronc zoo in queens
27
Why was the virus so successful?
there were a lot of birds present in the city
28
What is the distinct clinical syndromes in NSW 2011 of the arbovirus
* Myalgia and arthralgia
| * Neurological signs and encephalitis
29
How do you monitor the arbovirus outbreak
```
Monitoring:
Disease in vertebrate host
Antibody in vertebrate host
Presence of vector
Presence of virus in vector
```
30
What is a good indicator whether a place is safe
Presence of vector
Presence of virus in vector
before arriving
31
What causes Bluetongue
African Horse Sickness
Equine Encephalosis
Genus
| Orbivirus
32
What does blue tongue infect
Disease of sheep, cattle and goats
33
What are the clinical signs of blue tongue
Hyperaemia of oral and buccal cavities (salivation / frothy mouth)
Nasal discharge (serous – mucopurulent – blood flecked)
Cyanosis of the tongue
Hyperaemia of the coronary bands
Oedema (head and neck)
34
Why was it hard to cure blue tongue
there are 25 setypes of bluetongue, and are different virulence
35
What are the control for bluetongue
Vaccination programmes
Monitoring schemes: Vector and host surveillance
Live attenuated vaccines are available and used overseas
36
What are the reservoir host of african horse sickness
horses
37
What are African Horse Sickness
Peracute pulmonary form:
Nasal discharge progressing to respiratory distress and often 100% mortality
difficult to breath due to oedema
38
What is the definition of infection
entry and development or
multiplication of an infectious agent in the
body.
39
What is the definition of disease(infectious)
clinical and/or
| pathological manifestation of infection
40
What is anthroponosis
from infected humans [farmers, owners, veterinarians...] to
| animals
41
What is the Basis of host specificity
• Presence/absence of Host receptors for
colonisation; presence/absence of Pathogen
adhesion systems or other virulence factors
• Persistence within tissues, macrophages, and
translocation
• Frequency of contact between different host
species or mode of contamination
• Host-specific immune responses
42
What is the difference between Salmonella Gallinarum vs. Salmonella Dublin in
experimentally infected calves
– Dublin and Gallinarum are both able to colonize
and invade bovine intestines, BUT...
– Dublin persists within the mucosa and tranlocates
in lymph more than other serovars
43
Major cause of antibiotic resistance in human pathogens
```
is the (over) use of
antibiotics in humans rather than animals.
```
44
Where does Enterotoxinogenic E. coli (ETEC) fimbriae colonise
– Colonise the intestine and cause diarrhoea
| toxins
45
Is virtually all animal-derived human pathogens arose from
| pathogens of other warm-blooded vertebrates
yes
46
What increases the Probability of cross-species infection
* abundance of the existing donor host
* frequency of encounters with donor host
* phylogenetic distance between the hosts
* pathogen variability
47
How many percent of the zoonotic pathogen do not persist
• approx. 25% do not persist in humans without
| repeated reintroductions from animals
48
What is 1: agent
only in
animals type of transmissibility
Not zoonotic
49
2: primary
| infection
None, only from
| animals
50
3: limited
| outbreak
From animals or
humans (few
cycles)
51
4: long
| outbreak
From animals or
humans (many
cycles)
52
5: exclusive
human
agent
Only from
| humans
53
What evolution does Yesinia pestis have
* Lost genes encoding urease, toxic for fleas
| * Gained genes helping flea gut colonisation
54
What is one disease that is anthroponotic
S. aureus infection in broiler
| chickens
55
What does ELISA detect
antibodies
56
What can serum component do
```
• Neutralize toxins
• Agglutinate bacteria
• Precipitate toxins
• Lyse bacteria (with assistance of
complement)
```
57
What are antibodies produced by
B cells
58
What does antibodies recognise
recognise antigens in a specific way
59
What is the basic structure of antibody
2 heavy chains and 2 light chains
60
What is an epitope
An epitope is a part of an antigen that is recognised by
| immune system
61
What is a paratope
A paratope is the part of the antibody binding the antigen
√ The paratopes is defined by a combination of the variable
region of the heavy and light chains of the antibody
62
Where can B cell epitopes be accessed?
B cell epitopes are
| accessible from the outside
63
Where are B cell epitope located
```
– Exposed on the surface of the
cell
• Antibodies are hydrophilic and
water soluble
• Antibodies can not pass
through the plasma membrane
```
64
What does the choice of isotype depend on
– Depends on cytokine environment
| – Depends on type of T cell help provided
65
What is the full name for ELISA
ELISA = Enzyme-Liked Immuno-Sorbent Assay
66
What is are the steps for indirect
1. Antigen - coated well
2. Add specific antibody to be measured
3. add enzyme-conjugated secondary antibody
4. Add substrate (S) and measure color
67
What are the steps for sandwich ELISA
1. Antibody-coated well
2. Add antigen
3. Add enzyme-conjugated secondary antibody
4. Add substrate and measure color
68
What is the meaning indirect of captured antigen
– Often using a detection antibody and an antibody to the
detection antibody (i.e. indirect detection)
– Amplification (several enzyme linked antibodies bind to 1
detection antibody)
– Capture antibody and detection antibody MUST be different
• Different species
• Different isotypes
69
Why is indirect detection flexible
– Increased flexibility (only needs one enzyme linked reagent
70
What is streptavidin
– Very strong binding to biotin
– Increased flexibility
• Can be bound to fluorescent molecule (FITC)
• Can be bound to enzyme for ELISA
– One streptavidin molecule can bind 4 biotin molecules and
several enzymes can be bound to one stretavidin molecule
• Amplification
71
What is sandwich ELISA
• Epitope recognised by the capture and detection Ab
needs to be different
• Capture Ab needs to be relatively pure as the binding
to the ELISA plate is by adsorption and this non-specific
72
What is the difference between IgG and IgM
IgM is the first stage of the antibody, or the first time it was affected
73
What is class switch
changing from IgM to IgG
74
Is class reversible
Class switch is irreversible
75
How many antibodies does one be cell produce
one, epitope
76
How to immortalise b cells
Thymidine Kinase (TK)
mutant method
Thydmidine: rescue of nucleotide synthesis pathway
77
Why cancer cell can never die
Cancer cell has a mutation in the Thymidine Kinase gene (TK-) to achieve this.
78
What does aminopterin do
blocks pathways for synthesis of nucleotides
79
How help to cancer cell survive in HAT
In the presence of hypoxanthine
| and thymidine a rescue pathway exists provided that thymidine kinase (TK) and HGPRT enzymes are present.
80
How to select TK- myeloma cells
– Myeloma cells are naturally TK+
– To make TK- myeloma cells culture in presence of
bromodeoxyuridine
– The bromodeoxyuridine gets incorporated into the
DNA and kills the cells only TK- cells survive
81
How to select Ab negative myelomas
Myeloma cells used for fusion are derived from B
cells and normally make their own antibodies
– This would result in mixed Ab secretion (native Ab of
fusion partner, native Ab of spleen cells and mixed
Ab with different specificity)
– Need to select for H and L chain negative mutants so
that only native Ab of spleen cells are remaining
82
What is the diagnostic application of monoclonal antibodies
Detection of specific proteins
• Detection of specific small molecule (i.e. competitive dip-stick test)
– Detection of antibiotic in milk
83
what is the use of PCR
It’s a quick, easy way to create copies
| of DNA from a small starting input
84
What is the annealing temperature
5 degree different from the melting temperature oh primer(lower)
85
What is the effect of MgCl2 in PCR
• Cofactor of DNA polymerase
86
what can high Mg2 concentration cause
increase PCR yield but
| decrease the specificity of the reaction
87
What can low Mg2 concentration cause
Lower Mg2+ concentrations increase specificity, but
| decrease yield.
88
What differs Conventional PCR vs qPCR
```
qPCR Uses non-specific DNA binding dyes
(SYBR GREEN)
2. Uses labelled probe that binds
between forward and reverse primers
(Taqman)
```
89
What is Cycle threshold (CT
| )
– The cycle number at which the
| signal crosses the threshold line.
