avian viral diseases 2 - Tesse Flashcards
Pox virus is ____ shaped
brick
which 3 viruses have a segmented genome
influenza viruses
birna viruses
rotaviruses
AVian pox target cells
epithelial cells in the skin
epithelial hyperplasia and ballooning degeneration, with borrel bodies are found with:
avian pox virus
Avian pox targets ____ areas
unfeathered
what are the two forms of avian pox virus
cutaneous (dry)
wet
Cutaneous form of pox virus transmission
abrasions, mosquito bites and cannibalism
what is the mortality of cutaneous avian pox virus
low
which is more severe: cutaneous or wet avian pox
wet
transmission of wet avian pox
aerosolized virus in poultry -> respiratory
what is the tracheal lesion found in the wet form of avian pox
diffuse necrosuppurative tracheitis with locally extensive diptheretic membrane
Avian pox diagnosis
drop pox virus on chorioallantoic membrane of 9-11 day old. Pox virus will create plaques on the membrane 6 days postinoculation
Control of avian pox
vaccination via wing web method (chickens and pidgeons) or drumstick stab method (turkey)
Recombinant vx are available as well, as avian pox is the backbone of many other disease vaccines (infectious laryngotracheitis, newcastle) for in ovo or day 1 post hatch
monitoring avian pox vaccine take
scab or swelling at site of vaccine administration in wing web area 8-10 days post vx indicates development of immune response against fowl pox
what is the importance of pox virus
- used as a vector for vaccines
- causing disease
infectious bursal disease (gumboro disease) etiology
Family: birnaviridae
genera: avibirnanirus (IBDV)
which serotype of IBDV is non-pathogenic?
serotype 2
which serotype of IBDV is pathogenic
serotype 1
what are the three subgroups of IBDV-1
classic/standard (10-50% mortality)
variant (no mortality) but immune suppression
very virulent (50-100% mortality)
Clinical IBDV is common in what age of birds
3-6 weeks of age
which two species get subclinical IBDV in the absence of immunosuppression
turkeys and ducks
IBDV has a tropism for what type of cells in what organ
dividing pre-B cells in the bursa of fabricius
pathogenesis of bursa of fabricius atrophy in IBDV
inflammation of B of fabricius -> B cell necrosis and apoptosis -> acquired B lymphocyte deficiency -> atrophy
What two avian viruses deplete B cells
Marek’s and IBDV
what is the gross appearance of the B of Fabricius in IBDV cases
inflamed and swollen with hemorrhages. It appears enlarged, edematous, hemorrhagic and gelatinous
IBDV on histology
immunohistochemical staining
Gross appearance of kidneys in IBDV
severe urate accumulation leading to a colour change
IBDV clinical signs
anorexia, depression, ruffled feathers, diarrhea, urates in urine
IBDV diagnosis
acute disease and bursal lesion suggest IBDV. virus isolation/RT PCR in the b of fabricius is confirmatory
control of IBDV
vaccination
-broilers: ED18, D1 and D14-21
-layers: D14-21
what are some things that can interfere with IBDV vaccination?
improper storage and/or preparation
uneven vx administration, often due to route of administration (in ovo is great, others not so much)
maternal antibody interference
How do maternal antibodies interfere with the IBDV vaccine?
If you want to vaccinate early (3 weeks), you have to use a very virulent vaccine to overcome maternal antibodies.
at 3-6 weeks, use an intermediate vaccine.
post 6 weeks, use an avirulent vaccine.
what are the two strategies for overcoming maternal antibody interference with avian IBDV vaccines?
- immune-complex vaccines (coat the vaccine virus in antibodies)
- vaccinate with decreasing virulence as maternal antibodies decline
how do immune complex vaccines counteract maternal antibodies
vaccine virus is protected with vaccine antibodies. with these vx antibodies coating the virus, the maternal antibodies can’t interfere with it. over time, the vx antibodies decay, and virus replication can begin AFTER maternal antibodies are depleted.
Chicken infectious anemia etiology
spherical, ss-non enveloped dna virus
family: circoviridae
genus:gyrovirus
T/F: chicken anemia virus is very susceptible to the environment
false. it is very resistant
how many serotypes of chicken anemia virus are there
1
what age of chickens develop clinical signs of chicken infectious anemia
only young chicks, although all ages can be infected
target cell of chicken anemia virus
T-cells
match the avian virus to the target cell:
- chicken anemia virus
- IBDV
a. B cell
b. T cell
1-> b
2->a
What are the three major impacts of chicken infectious anemia
- bad performance and increased mortality in broilers
- leading secondary infectious and vaccination failures
- vertical transmission from breeders to their progeny leading to clinical disease
What are the two avian viruses that can transmit vertically
chicken infectious anemia and avian leukosis virus?????? can someone fact check this????
T/F: chicken infectious anemia can be transmitted horizontally and vertically
true
which cells does chicken infectious anemia virus target
hemocytoblast ( progenitor cell to RBCs, heterophils, thrombocytes) and T lymphocyte precursor. These cells undergo apoptosis, resulting in anemia, immunosuppression
what is the most important consequence of CAV infection
immune suppression
Which flock should you vaccinate against CAV: breeder flock or commercial flock?
breeder flock.
(don’t ask me why. This lecture is a nightmare)
what is the significance of the incubation period of CAV
relatively long -> takes weeks to spread through entire flock
where does CAV replicate
in most lymphopoeitic organs
T/F: CAV enhances the effect of other immunosuppressive agents, such as mareks or IBDV
true
what is a gross lesion found in the neck of chickens that may indicate CAV
thymus atrophy
CAV gross lesions
subcutaneous hemorrhage, secondary bacterial infection leading to gangrenous dermatitis (“blue wing disease”). These are caused by anemia and immunosuppression respectively.
What happens to the bone marrow in CAV infected birds
atrophies, and is replaced by fat
control of CAV
maternal antibodies protect against CAV (so vaccinate your breeders!!)
when should you vaccinate breeders against CAV
between 8-16 weeks of age
Reo viral arthritis in broiler chickens causes ______ legs
“hockey stick” legs
a broiler is lame and has legs that look like hockey sticks. whats your diagnosis
reo viral arthritis
Reo virus has many variants. What does this mean for vaccines?
vaccine strains for reo virus do not protect against disease caused by the variant reoviruses
you are asked to vaccinate a flock of chickens to prevent pox viral infection. you administer the vaccine via
wing web innoculation
In ovo immune complex vaccines against infectious bursal disease (IBD):
a. consist 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. are used to stimulate innate immune responses rather than antibody-mediated immune responses
b. prevent maternal antibody interference
What gross lesion is found consistently in 4 week old broiler chickens infected with a field strain of infectious bursal disease virus
inflamed swollen bursa of fabricius with hemorrhages
What are the clinical signs of dry (cutaneous) avian pox
Follicular epithelial hyperplasia and folliculitis, hyperkeratosis and ulceration
What are the oral lesions found in wet avian pox
Severe multifocal to coalescing mucosal hyperplasia
