Infectious bursal disease and chicken infectious anemia

Question 1

What is infectious bursal disease?

Answer 1

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

Question 2

Who does IBD occur in?

Answer 2

primarily chickens

Question 3

What age of bird does IBD occur in?

Answer 3

Most severe in birds 3-6 weeks but can occur if they have a functional bursa (1-16wk)

Question 4

Why is IBD worse when a bird is infected earlier?

Answer 4

more severe immunosuppression and a higher degree of susceptibility to subsequent pathogens

Question 5

What happens once a premise has been contaminated with IBD?

Answer 5

The disease tends to reoccur, usually as subclinical infection

Question 6

What causes IBD?

Answer 6

virus of Birnaviridae family

Question 7

How many serotypes of IBD virus exist? Are they all pathogenic?

Answer 7

Two serotypes, only serotype 1 is pathogenic

Question 8

How resistant is the IBD virus?

Answer 8

very.

very resistant to most disinfectants and environmental factors persists for months. can be transmitted by fomites

Question 9

How does the IBD virus cause disease?

Answer 9

lymphocidal–severely damages the bursa of Fabricius (and thymus, spleen, cecal tonsils)

Question 10

What can be the effect of IBD on vaccination of birds against other diseases>

Answer 10

vaccine failure can occur because the chicks have damaged humoral immunity

Question 11

How is IBD transmitted?

Answer 11

horizontally (can be form contaminated premises/fomites or infected chicks).

Question 12

How contagious is IBD?

Answer 12

highly contagious

Question 13

What can harbor IBD virus?

Answer 13

the lesser meal worm

Question 14

Is there a carrier state for IBD?

Answer 14

no

Question 15

Can IBD be transmitted through eggs?

Answer 15

no

Question 16

What are clinical signs of very virulent IBD?

Answer 16

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

Question 17

How is IBD diagnosed?

Answer 17

1. acute outbreak in susceptible chicks, short course, bursal lesions
2. paired serology

Question 18

How is IBD controlled?

Answer 18

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

Question 19

What is chicken infectious anemia?

Answer 19

a disease of chickens caused by a circovirus. aplastic anemia, generalized lymphoid atrophy, subQ and IM hemorrhage, immunodepression

Question 20

Where is CIA found?

Answer 20

everywhere!

Question 21

Are chickens the only known hosts of CIA?

Answer 21

yes

Question 22

What animals are susceptible to infection? What animals become diseased?

Answer 22

Any age of chicken can be infected but clinical disease only seen in first 2-4 weeks. (unless IBD infection as well)

Question 23

What is the most important method of transmission for CIA

Answer 23

vertical (but also via feces)

Question 24

What are the clinical signs of CIA?

Answer 24

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

Question 25

What are the lesions of CIA?

Answer 25

1. thymic atrophy

2. fatty yellowish bone marrow (esp femur)

Question 26

How is CIA diagnosed?

Answer 26

1. clinical signs, gross lesions
2. isolation and ID of virus
3. serology
4. PCR–test of choice for ID of virus

Question 27

how is CIA controlled?

Answer 27

1. immunization of breeder flocks prior to onset of egg production–not too close because could transmit to egg!
2. exposure of breeder flocks to contaminated litter–risky