Flashcards in Infectious bursal disease and chicken infectious anemia Deck (27)
What is infectious bursal disease?
Acute, contagious viral disease of young chickens, characterized by diarrhea, vent pecking, trembling, incoordination, inflammation and then atrophy of the bursa of Fabricius and immunosuppression
Who does IBD occur in?
What age of bird does IBD occur in?
Most severe in birds 3-6 weeks but can occur if they have a functional bursa (1-16wk)
Why is IBD worse when a bird is infected earlier?
more severe immunosuppression and a higher degree of susceptibility to subsequent pathogens
What happens once a premise has been contaminated with IBD?
The disease tends to reoccur, usually as subclinical infection
What causes IBD?
virus of Birnaviridae family
How many serotypes of IBD virus exist? Are they all pathogenic?
Two serotypes, only serotype 1 is pathogenic
How resistant is the IBD virus?
very resistant to most disinfectants and environmental factors persists for months. can be transmitted by fomites
How does the IBD virus cause disease?
lymphocidal--severely damages the bursa of Fabricius (and thymus, spleen, cecal tonsils)
What can be the effect of IBD on vaccination of birds against other diseases>
vaccine failure can occur because the chicks have damaged humoral immunity
How is IBD transmitted?
horizontally (can be form contaminated premises/fomites or infected chicks).
How contagious is IBD?
What can harbor IBD virus?
the lesser meal worm
Is there a carrier state for IBD?
Can IBD be transmitted through eggs?
What are clinical signs of very virulent IBD?
1. initially bursa enlarged, edematous, reddened, may have hemorrhages
2. hemorrhages can occur in thigh, pectoral muscle, junction of proventriculus, ventriculus (toxemia)
3. variant IBD strains induce rapid bursal atrophy and severe immunosuppresion
How is IBD diagnosed?
1. acute outbreak in susceptible chicks, short course, bursal lesions
2. paired serology
How is IBD controlled?
1. vaccination of breeders multiple times up to before laying
2. can vaccinate chicks but difficult to time b/c have maternal immunity
3. in ovo
4. sanitation--not very successful
What is chicken infectious anemia?
a disease of chickens caused by a circovirus. aplastic anemia, generalized lymphoid atrophy, subQ and IM hemorrhage, immunodepression
Where is CIA found?
Are chickens the only known hosts of CIA?
What animals are susceptible to infection? What animals become diseased?
Any age of chicken can be infected but clinical disease only seen in first 2-4 weeks. (unless IBD infection as well)
What is the most important method of transmission for CIA
vertical (but also via feces)
What are the clinical signs of CIA?
1. anemia (6-27%)
2. depression, pale tissues, decreased weight gain, secondary infectioun
3. mortality variable--depends on other infectiouns
4. inteference with vaccination against marek's, IBD
What are the lesions of CIA?
1. thymic atrophy
2. fatty yellowish bone marrow (esp femur)
How is CIA diagnosed?
1. clinical signs, gross lesions
2. isolation and ID of virus
4. PCR--test of choice for ID of virus