Virology

Question 1

What are Koch’s postulates?

Answer 1

1. microrganism found in diseased but not healthy individuals
2. microorganism must be cultured from the diseased individual
3. inoculation of healthy individual with culutred microorganism must recapitulated the disease
   4.microorganism must be reisolated from inoculated, diseased indiviual and matched to original microorganism

Question 2

What is the point of Koch’s postulates?

Answer 2

criteria designed to assess whether a microorganism causes a disease

Question 3

What is propagation of a virus?

Answer 3

To multiply, a virus has to enter a living cell. Thereafter, the viral genome is released from the capsid, and interacts with the host cell in order to replicate and to produce viral proteins.

Question 4

Why propagate a virus in a chicken egg?

Answer 4

-specific pathogen free
- isolate the virus
-inoculate membrane that best supports specific virus
- convinient for growing high titre stocks of viruses

Question 5

What are the requirments for culturing cells?

Answer 5

culutre flasks
tissue culture medium
cell culture incubator
sterile technique
safe working environment

Question 6

What is passaging cells?

Answer 6

Passaging cells (or splitting cells) involves taking a
fraction of cells from a cell culture and diluting those
cells in fresh medium in new dish. The passage number
of a cell line is used to keep track of how long a cell
line has been cultured for, and each passaging event
will represent a number of cell divisions

Question 7

What is the cytopathic effect?

Answer 7

Morphological chances induced by viral infection

Dependant on:
- the virus
- cell type
- multiplicity of infection
- time point
- isolate
-mutations

Question 8

WHat can plaque assays be used for?

Answer 8

– Quantify virus stock (pfu).
– Purify a virus stock (make clonal).
– Assay attenuation of virus stocks.
– Determine particle-to-pfu ratio.
– Generate/select recombinant viruses

Question 9

Parvoviridae properties

Answer 9

ssSND
non eneloped
small
icosahedral
RESISTANT (heat, disinfectants. pH)
only replicate in nucleus of dividing cells
(parvovirus)

Question 10

Signif parvoviruses

Answer 10

Canine parvovirus (highly contagious/ in utero)
feline panleucopaenia virus (abortions)
porcine parvovirus (SMEDI)
bovine parvovirus
goose/chicken/ duck parvovirus

Question 11

Patho of parvo

Answer 11

nasal or oral
- needs dividing cells
replicates in nucelus leaving intranuclear inclusion body
*big impacts on newborns and foetus as have lots of cell division

• bone marrow and interstinal crypts
  -continous rep
  highly suseptible to infection

Question 12

Immunity to parvo

Answer 12

annual booster
killed and live attenuated vaccines
(6-8 weeks of age, continue monthly)
3 shots enough
maternal antibody via colostrum protects newborn

Question 13

Parvo diagnosis

Answer 13

antigen in faecal, blood or tissue sample
haemagglutination assays
ELIZA or RIM
PCR
Immunohistochemistry

Question 14

Porcine parvo charactersitics

Answer 14

repro failure in pigs
Stillbirth Mummification Embryonic Death Infertility (SMEDI)
very resistant (70-73* for 30-60 mins to deactivatea)
endemic in herds
infected pig (viremia) –> sheds oral and feacal secretions
carrier boars (screen semen used for AI)

Question 15

Porcine parvo patho

Answer 15

infected pigs –> viremia –> without clinical disease or obvious lesions
strong humoral response
seroneg sows exposed during gestation cause repro issues
Virus loves foetal tissue

Question 16

Porcine parvo treament

Answer 16

no treatment
endemic
vaccinate breeding gilts and suseptible sows prior mating
vaccine (2-4 weeks prior mating)
boosters 6-12 months

Question 17

Porcine parvo prevention

Answer 17

biosecurity
quarantine nd screen
antibody or antigen testing
control human movement
allin-allout

Question 18

Canine parvo prevention

Answer 18

dogs secrete 3-4 days before clinical signs
isolation
footbaths
disposable clothing, bedding
disinfecting
puppy vaccines

Question 19

Papillomaviridae properties

Answer 19

dsDNA
non enveloped
icosahedral
stable in ennviro
RESISTANT (heat, lipid solvents, disinfectants)
loves epitheliol cells
hst specific
*unable to grow in cell culture

very species specific
WARTS (cell mass into papilloma)

Question 20

Signif Papillomaviridae

Answer 20

Bovine
- type 1&2 (young cattle - head, neck, penis)
(equine)
- type 3 (cutaneous pap)
- type 4 (alimentry tract)
- type 5 &6 (teat)

Equine (young, lips and muzzle)
Canine oral (young)
Ovine(sheep)

Question 21

Papillomavirus diagnosis

Answer 21

clinical apperance
histopathology
EM to look for virus in tissue
PCR
CANT CULTURE

Question 22

Equine sarcoids

Answer 22

– Locally invasive dermal fibroblastic skin
tumour
– Locally aggressive but not metastatic
– Benign skin tumour
– Most often on ventral abdomen, limbs,
head and sites of previous trauma
– Occur as a single or multiple lesions
– DO NOT REGRESS !!
* EPV regress in 4 - 8 weeks

Caused by BPV types 1 or 2

Question 23

Equine sarcoid risk factors

Answer 23

age (2-6)
breed (quater>throurough>standard)
genetic suseptibility
absense of immune recog

Transmission (cattle –> horse/horse–>horse
SKin abrasions

Question 24

equine sarcoid diagnosis

Answer 24

PCR
qPCR
Biopsy
histopathology

Question 25

equine sarcoid treatment

Answer 25

surgical excision
cryotherapy
immunotherapy
radiofrequency hyperthermia
laser surgery
siRNA

Question 26

Poxviridae properties

Answer 26

large
complex structure
dsDNA
enveloped
BREAKS A LOT OF RULES

can survive in environemnt (yearsvin dried scabs)
sensitive (heat/detergent)
ONLY REPLICATE IN CYTOPLASM (inclusion bodies)
predilection liking) for epidermal cells

Question 27

SIgnnif pox viruses

Answer 27

Smallpox
Vaccinia
Cowpox
Camel and mouse pox
Parapoxvirus (ORF) –> scabby mouth)
Pseudocowpox
Bovine papular stomatitis virus
Croc and caiman pox
Capriopox (sheep and goat)
Suipoxvirus (swine pox)
Leporipoxvirus (myxoa)
avipoxvirus(fowlpox)

MANY ZOONOTIC-> localised skin lesions

Question 28

Pox path

Answer 28

contagious
small abrasions (between animals) –> direct and indirect
Vectors
Aerosols
ALL CAUSE SKIN LESIONS
like epiderml cells
cell associated viremia
viral rep and assembly in cytplasm
virions releasrd (budding)
LIVE VIRAL VACCINES NEEDED

Question 29

Pox diagnosis

Answer 29

clinical apperance
histopathologgy
isolation of irus in cell culture
EM
PCR

Question 30

Pox prevention

Answer 30

Vaccine (only commercial and lab rabbits)
live modified
not permitted for pet rabbits (vaccine)
ectoparasite control
pet rabbits in rural areas

Question 31

Scabby mouth properties

Answer 31

ORF
sheep and goats
pustular dermititis
zoonotic
muzzle nd lips
scabs
eyes, lower legs, teats

Question 32

Scabby mouth spread

Answer 32

direct or indirect
dry stable environ
epitheliotropic

Question 33

What are diagnostic methods to detect the virus itself?

Answer 33

• growth in culture
• Nucleic acids (PT-PCR, PCR)
• Antigens (ELIZA, IFA, IB/WB, LFT/RAT)
• Activities (HA)

Question 34

What are diagnostic methods to detect the immune response to a virus?

Answer 34

• Antibiodies (ELIZA, HAI, virues
• neutralisation (IGA< IB/WB)

Question 35

What are Prions?

Answer 35

– Infectious proteinaceous particles
– “Infectious proteins”
– Lack nucleic acid
– Non-immunogenic
– Extremely resistant to:
– Heat
– Chemicals
– Irradiation
– Cause Transmissible Spongiform
Encephalopathies (TSEs)