L11: Marek's Disease Flashcards
1
Q
Cause of marek’s disease
A
Alphaherpesvirus
-causes solid lymphoid tumors that originate in the thymus-derived lymphoid (T) cells**
2
Q
Incubation period of marek’s disease vs. lymphoid leukosis (LL)
A
Marek’s disease has shorter incubation period (
3
Q
How many serotypes of Marek’d disease?
A
3
1 and 2 are in chickens
3 is in turkeys
4
Q
Trans. Of marek’s disease
A
- feather follicle epithelium is the virus “gateway” to contaminate poultry house environment**
- cell desquamation, feathers, dander
- most likely via resp. Route
5
Q
CS of Marek’s disease**
A
4 key syndromes:
1) neural lymphoma –> drooped wings, legs extended, torticollis, paralysis
2) ocular lymphoma –> blindness
3) cutaneous lymphoma
4) visceral lymphoma
6
Q
Necropsy of Marek’s disease
A
- neoplastic nerve lesions
- rarely, a diffusely enlarged bursa of F
- iris invaded by lymphoid cells
- “bumps” on skin/feather follicles
- red leg
- tumors on combs, GIT, liver, lungs, muscle, heart, repro organs, etc.
7
Q
Dx of Marek’s disease: differentiate from LL***
A
- Marek’s seen in younger birds
- Marek’s has INTERfollicular microscopic tumors, PLEOMORPHIC lymphoid infiltrates, and NERVES infiltrated by lymphoid cells
- paralysis and paresis seen in Marek’s
8
Q
Prevention of Marek’s disease
A
- vaccination in ovo or on day of hatching
- biosecurity
- all-in/all-out
Vaccination for serotypes 2 and 3 have protective synergism**
Do NOT use serotype 2 vaccines alone!
