Cause of chicken infectious anemia
- circovirus
- a hardy ss DNA virus
- ubiquitous worldwide
Which chickens are most affected by chicken infectious anemia
Broilers and layers
Only natural hosts of chicken infectious anemia
Chickens
Trans. Of chicken infectious anemia
Vertical transmission is most important
Also horizontally
When is clinical disease seen with chicken infectious anemia**
Only during first 2-3 weeks of life, after which chicks become resistant. However, ALL ages are susceptible to infection
CS of chicken infectious anemia
ANEMIA = only specific sign
Low PCV
Blood may be slow to clot, prone to bleeding
Birds pale, depressed
Mortality of chicken infectious anemia
5-10%, can be up to 60%
Exacerbating “factors” of chicken infectious anemia
Marek'd dz Infectious bursal dz Inclusion body hepatitis virus Staph Clostridium Mycotoxins Stress
Sequelae of chicken infectious anemia
- aplastic anemia
- generalized lymphoid depletion
- SC and IM hemorrhages
- immunosuppression
- secondary infections –> high mortality
Dx of chicken infectious anemia
- CS, gross lesions
- PCR, IF, IHC, ELISA
Prevention of chicken infectious anemia
- live modified virus vaccine protects parental flocks and passively protects chicks
- most flocks naturally exposed
- vaccinate 6 wks prior to onset
- vaccinate ALL birds and avoid spreading it to younger birds or layers
Infectious bursal (Gumboro) disease cause
Birnavirus
-a highly contagious, stable virus
Trans. Of infectious bursal (gumboro) disease
Fecal/oral, highly contagious
NO egg transmission, no carrier state**
What species/age affected by gumboro dz?
Only chickens, usually chicks 3-6 wks
2 forms of Infectious bursal (Gumboro) disease
1) sub-clinical: immunosuppression w/o CS; most economically important
2) clinical: rapid increase in mortality, 3-4 wks
CS of Infectious bursal (Gumboro) disease
- rapid onset
- ruffled feathers
- depression, anorexia
- watery white diarrhea
- severe prostration
- death
Gross lesions of Infectious bursal (Gumboro) disease
- swollen, exudative, hemorrhagic bursa of F**
- Hemorrhages in muscles +/- kidneys, proventriculus, gizzard
- renal tubules distended w/ urates
Cardinal microscopic lesions of Infectious bursal (Gumboro) disease
- mostly in the bursa of F
- necrosis of lymphocytes in follicles
- edema, hyperemia, heterophils
- cystic cavities
- interfollicular fibroplasia
- follicular atrophy
Dx of Infectious bursal (Gumboro) disease
- virus isolation in egg
- impression smears from bursa
- IF, PCR
- Agar gel precipitation (AGP)
- must determine pathotype of field virus involved in outbreak
Virulent strains –> INTRAfollicular staining
Non-virulent strains –> INTERfollicular staining
Importance of ELISA with Infectious bursal (Gumboro) disease**
Used for monitoring vaccination response and maternal Ab persistence in young chicks
Why vaccinate YOUNG CHICKS against gumboro disease?
Prevents immunosuppression, Mb, Mt after natural infection
Why vaccinate BREEDERS against gumboro disease?
To stimulate development of high and persistent levels of Ab to be transferred to progeny during laying period
Ab for Gomboro dz persist longer in layers or broilers?
Layers (7 vs. 4 days)