lecture 13/ -avian virology Flashcards
fwhat is MD
Marek’s disease
what virus causes MD?
mardiviruses, which are herpesviruses
what organs are infected by MDV?
skin, lungs, immune, adrenal glands, liver, GI, etc
where are infectious viral particles of MD made?
feather follicle epithelium
how is MDV transmitted?
inhalation of feather dander in environment
since it is a herpes virus, MDV establishes….
latency
where does MDV establish latency? how is this dif from other herpesviruses?
what do these cells become?
latency mainly in CD4+ T cells (versus trigeminal ganglia)
T cells become tumor cells
what pathology is noted when a bird is infected with MDV?
visceral and neural lymphomas
what are some cliical manifestations of MD?
chronic polyneuritis
visceral lymphoma
immunosuppression
transient paralysis
acute brain oedema
acute rash
how has vaccination influence the virulence of MDV, historically?
increasing virulence
as virulence increases, how are the spleen, bursa of fabricius, and thymus impacted?
you are presented with a broiler chicken that has neck paralysis, dyspnea, skin tumors, and irregular pupils. what virus are you concerned about
MDV
how can the sciatic nerve gross appearance be used to help diagnose MDV?
loss of striation, discoloration, swollen
what is unique about the latency of MDV versus other herpesviruses?
establishes latency in cd4 t cells versus trigeminal ganglion
what kind of virus causes avian leukosis tumors
retrovirus
where will you NOT find tumors with avian leukosis ?
skin, muscle, nerves, proventriculus
what differentiates the bursa of fabricius in marek’s disease vs avian leukosis
mareks- enlarged, sometimes tumorous
leukosis- nodular
what is the neoplastic immune cell involved with mareks disease? what about avian leukosis?
mareks-t cells
leukosis- b cells
how does transmission differ between mareks disease and avian leukosis?
avian leukosis has vertical transmisison!! in addition to horizontal
mareks is only horizontal
do MDV vaccines prevent infection?
no, but they prevent tumor formation
at what day are eggs moved from setter to hatcher compartment? what is it called when we vaccinate at this time?
day 18
in ovo vaccination
something else about vaccine strat in ovo…. broilers are the only animal known- special
why is it beneficial to vaccinate broilers in ovo?
less probability of being infected with MDV (shorter window of susceptibility)
less labour - you are transporting at day 18 anyways
why does layer industry not use in ovo tech
we use only females with layers and the machine cannot differentiate sex –> vaccines would be wasted on males (lol)
what is it called when you vaccinate after birds hatch
what is ILT
infectious laryngotracheitis
what family is ILTV a part of
herpesviridae
ILTV is endemic in ____
backyard flocks
how is ILTV transmitted
eye drop, direct contact, shared airspace
what are the gross lesions of ILTV
blood, mucus, and yellow caseous exudate or a hollow caseous cast in the trachea
a chicken presents with blood tinged mucus, conjunctivitis, and is dyspnic. what virus do you suspect?
ILTV
what is seen on histology of the trachea and conjunctiva with ILTV
syncytia cells
where is ILTV cultivated within an egg? what other virus can be cultivated here?
chorioallantoic membrane
avian pox virus too
how neat are the modified live ILVT vaccines? is there another option?
not very!! its like orf - lots of disadvantages
could give recomb fowlpox/HVT vaccine with ILTV genes
no inactivated vaccine
true or false- ILTV replicates superficially in the epithelium
false – goes quite deep
what is the best way to avoid ILTV infection
good biosecurity
what is IB? what kind of virus?
infectious bronchitis
coronavirus
depending on the strain, IBV causes disease of…
respiratory, renal, myopathy, reproductive, and gastro
major clinical signs of IBV
dyspnea, discolored eggs, irregular shaped eggs, water albumin
what virus is associated with shell-less egg syndrome
IBV
what cells does IBV target
epithelial cells
what virus (and strain) is associated with false layer syndrome?
IBV, specifically the Delmarva strain
how does IBV lead to false layer syndrome
Delmarva strain leads to cystic oviduct leads to false layer syndrome
what is the pathology of nephropathogenic IBV strains?
urate deposition in kidney / tubules –> leads to mortality
what tissue samples would be helpful to test for IBV?
nasal, tracheal, kidney, intestinal, caecal tonsils*
Which of the following statement about in ovo vaccination
against Marek’s disease (MD) is TRUE?
a Vaccination usually takes place seven days before hatch
b Vaccine is inoculated into the yolk sac
c In ovo vaccination is not as effective as post-hatch vaccination
d Vaccine is inoculated into the amniotic cavity
e Vaccine is inoculated onto the chorioallantoic membrane
d Vaccine is inoculated into the amniotic cavity
Marek’s disease (MD) is different from avian leukosis since:
a The MD is caused by a retrovirus but avian leukosis is caused by a herpesvirus
b MD is characterized by visceral tumors and avian leukosis is
characterized by lymphoid depletion
c MD but not the avian leukosis is characterized by neurological
signs
d Causative viruses of both MD and avian leukosis are transmitted
vertically
e Both MD and avian leukosis are commonly seen in 1-7 days old
chickens
c MD but not the avian leukosis is characterized by neurological
signs
Infectious laryngotracheitis virus (ILTV) infection:
a Leads to anemia and diarrhea in addition to respiratory signs
b Is endemic in commercial flocks in Canada and rest of north
America
c Is an acute infection and the causative virus is cleared in 7-10
days post-infection
d The causative virus belongs to the Family, Retroviridae
e Is characterized by dyspnea and blood-tinged respiratory mucus
e Is characterized by dyspnea and blood-tinged respiratory mucus
What is NOT true about Infectious bronchitis virus (IBV)
infection:
a Causes egg production drops and poor egg quality
b Is endemic in commercial flocks in Canada
c Vaccines are not available for the control
d The causative virus belongs to the Family, Coronaviridae
e The clinical signs include respiratory clinical manifestations
c Vaccines are not available for the control
False layer syndrome (FLS):
a Leads to poor egg quality
b Is considered a foreign animal disease in Canada
c Is associated with development of cystic oviduct lesions
d The causative virus belongs to the Family, Herpesviridae
e Affected birds suffer from respiratory clinical signs
c Is associated with development of cystic oviduct lesions
what is seen on histo with avipox
epithelial hyperplasia and ballooning degeneration
what is special about replication with Pox viruses?
replicates in cytoplasm instead of nucleus, despite being a DNA virus
something about gross lesions of dry avipox
something about wet avipox
how is dry avipox transmitted
abrasions, mosquito bites, cannibalism
how is wet avipox transmitted
aerosols
how are vaccines delivered for axipox
wing-web method in chickens/pigeons, drumstick stab - turkeys
how can you check if a vaccine against fowlpox worked?
look for scab / reaction site
what is unique about the genome of infectious bursal disease (Gumboro disease)
segmented
how many serotypes of IBDV are there? subgroups?
2
1 has 3 subgroups (classic, virulent, very virulent)
2 is nonpathogenic
when is clinical disease common if a chicken becomes infected with IBDV
3-6 weeks of age
IBDV has a tropism for dividing ______ in _____
IBDV has a tropism for dividing pre B cells in B of Fabricius
chicken presents with D+, anorexia, depression, ruffled feathers, and the vent feathers are stained with fecus and urates.
what are you concerned about
IBDV
what are strategies to use to protect against maternal antibodies (concerning IBDV)
short answer q**
choose appropriate vaccine type (whether its classic, virulent, or very virulent)
immune complex vaccine
what is CAV
chicken anemia virus
what does CAV target? what is the result
targets thymus –> prevents maturation of T lymphocytes
what family and genus is CAV a part of
family Circoviridae and the genus Gyrovirus.
where are clinical signs seen with CAV? (what age)
younger than 2-3 weeks
true or false: the transmission of CAV is horizontal only
false - vertical too
broiler presents with lameness (hockey stick legs) - what are you concerned about
reo viral arthritis
You are asked to vaccinate a flock of chickens to prevent pox viral infection. You administer the vaccine via
a In ovo route
b Intramuscular
c Wing web
d Drinking water
e Aerosols
c Wing web
In ovo immune complex vaccines against infectious bursal disease (IBD)
a Consists of T cells and the vaccine virus in one formula
b Prevent maternal antibody interference
c Provide passive as well as active immunity
d Provide passive immunity only when maternal antibody levels are low
e Used for stimulating innate immune responses rather than antibody-mediated immune responses
b Prevent maternal antibody interference
