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93 Cards in this Set

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What is the most common lymphoproliferative disease of backyard chickens?
Marek's Disease
What is Marek's Disease also known as? (3 things)
range paralysis
polyneuritis
grey eye
What is the causitive agent of Marek's Disease?
herpesvirus
In Marek's Disease, what is infiltrated by pleomorphic lymphoid cells?
peripheral nerve trunks and the viscera
In Marek's Disease what infiltrates peripheral nerve trunks and the viscera?
Pleomorphic lymphoid cells
What is the most common lymphoproliferative disease of backyard chickens?
Marek's Disease
What is Marek's Disease also known as? (3 things)
range paralysis
polyneuritis
grey eye
What is the causitive agent of Marek's Disease?
herpesvirus
In Marek's Disease, what is infiltrated by pleomorphic lymphoid cells?
peripheral nerve trunks and the viscera
In Marek's Disease what infiltrates peripheral nerve trunks and the viscera?
Pleomorphic lymphoid cells
In what year was Marek's disease first described?
1907
When was the herpesvirus that causes Marek's disease attenuated and used as a vaccine?
1970
What distinction does Marek's disease have in cancer research?
It is the first practical effective anti-cancer vaccine in any species.
What season are broilers most affected by Marek's disease?
Winter
What is the natural host of Marek's disease? What other species might one find it in?
Chickens are primary natural host, may see in quail
Is Marek's disease transmitted directly or indirectly?
Both.
How is Marek's disease transmitted?
Virus replicates in the epithelial cells of feather follicles. Virus associated with feathers and dander is infective.
Egg transmission is rare.
A chick infected with Marek's disease at 1 day would start shedding virus when? When will clinical signs and gross lesions appear?
2 weeks shedding
3-4 weeks clinical signs and gross lesions
What age chickens most commonly show clinical signs?
4-16 weeks
What are the clinical signs of Marek's disease?
Asymmetric progressive paresis (eventually paralysis) of one or more extremity
What is the characteristic stance with Marek's disease?
One leg outstretched forward, the other backward due to unilateral sciatic neuritis, with drooping of one wing (if wings are involved)
What causes transient paralysis in young adults due to lymphocytic meningoencephalitis with edema?
Marek's disease
Why does blindness occur with Marek's disease?
Depigmentation of iris due to mononuclear infiltration of iris.
What gross lesions are seen in peripheral nerves with Marek's disease?
localized or diffuse enlargement (2-3x), loss of cross-striations, yellow to gray-white discoloration, lesions often unilateral
With Marek's disease, where are visceral tumors most common?
liver, spleen, kidney, proventraculus, uterus/ovary and heart
T or F:
Marek's disease often involves the bursa of Fabricius
False, it rarely does
T or F: Marek's Disease can cause cutaneous tumors
T, they have a distinct follicular orientation
What type of infiltrate is in the peripheral nerves in Marek's disease?
-neoplastic - lymphoblastic cells
-inflammatory cell infiltrates - small lymphocytes and plasma cells
What type of infiltrate is in the iris in Marek's disease?
neoplastic infiltrates
What type of infiltrate is in the visceral tumors in Marek's disease?
-pleomorphic neoplastic lymphocytes
-small to medium lymphocytes, lymphoblasts and primitive cells
-T-cell lymphoma
What percentage of commercial flocks are vaccinated against Mareck's disease?
virtually 100%
When are broilers vaccinated for Marek's disease?
18 days of incubation - with a machine.
T or F: Immunity from vaccination for Marek's disease is considered lifelong.
True
What is the treatment for Marek's disease?
No effective treatment
T or F: Birds can be slaughtered with Marek's disease.
F, they will be condemed at slaughter.
What group of poultry diseases does Lymphoid Leukosis belong to?
The "sarcoma group"
What is the causitive agent of Lymphoid Leukosis?
a retrovirus
A viral-induced neoplastic disease of young adult & mature chickens characterized by neoplasia of the bursa of Fabricius with metastasis to many internal organs describes what?
Lymphoid Leukosis
What five classes of neoplasms belong to the leukosis/sarcoma group?
Leukoses
Connective tissue tumors
Epithelial tumors
Endothelial tumors
CNS tumors
T or F:
Lymphoid Leukosis is a common disease of commercial broilers
False, mortality is common in chickens > 16 weeks
What is the most common transmission method for Lymphoid Leukosis? (Horizontal or Vertical)
What is the most important method of transmission?
Most common: Horizontal - bird to bird
Most important: vertical, because it allows spread from generation to generation.
What does it mean that chicks hatched from infected eggs are permanently viremic?
The are immune tolerant because they do not develop antibody. The are at increased risk for developing lymphoid leukosis. They will shed virus when in production (egg).
What are some clinical signs of Lymphoid Leukosis?
none to non-specific: pale comb and head parts, emaciated/unthrifty, may have enlarged abdomen (hepatomegaly), enlarged bursa of Fabricius, decreased egg production in flocks with high rates of infection.
Which disease infects younger chickens, Mareck's or Lymphoid Leukosis?
Mareck's disease
What gross lesions exist with Lymphoid Leukosis?
grossly visible tumors: nearly always involves the bursa of Fabricius. Tumors are creamy-white and bulge of cut surgace. Growth may be nodular or diffuse or a combo
What do the tumors consist of in Lymphoid Leukosis?
Monomorphic population of large, neoplastic lymphocytes where the predominant cell is the lymphoblast
Where do neoplastic cells originate from in Lymphoid Leukosis?
Bursal B-lymphocytes
T or F
Removal of the bursa in chicks prevents the development of lymphoid leukosis.
True
Cite differences between Marek's disease and Lymphoid Leukosis.
MD - younger birds, paresis/paralysis, lesions in nerves, CNS involvement, skin involvement, pleomorphic cells, NO tumors in bursa
LL - older birds, tumors in bursa, none of above, monomorphic cells
An acute, highly contagious viral disease of young chickens characterized by diarrhea, incoordination, and inflammation (followed by atrophy) of the bursa of Fabricius with immunosuppression
Infectious Bursal Disease
Also known as "Gumboro disease"
Infectious Bursal Disease
Infectious Bursal Disease aka what?
Gumboro disease
What is the causitive agent of Infectious Bursal Disease?
birnavirus (dsDNA virus)
What is the natural host for Infectious Bursal Disease?
Chicken
What age group does Infectious Bursal Disease primarily affect?
3-6 week old chickens, but may occur up to 16 weeks of age (length of functional bursa)
What modes of transmission does Infectious Bursal Disease spread?
Horizontal, no vertical (egg)
List some clinical signs of Infectious Bursal Disease
-sudden onset of diarrhea, tremors and incoordination
-ruffled feathers and droopy appearance
-vent picking
How long may the infective virus persist in litter for Infectious Bursal Disease?
Months
What gross lesions are seen with Infectious Bursal Disease?
Dehydration, petechial hemorrhages in thigh and pectoral muscles, enlarged and reddened bursa(initially), bursa atrophy by day 5 PI, bursa 1/3 original weight by day 8 PI
How fast does Infectious Bursal Disease spread through a flock?
Explosively! Morbidity high, mortality varies
List six causes of "sudden deaths" in chickens and turkeys.
1. Omphalitis
2. Colibacillosis
3. Cardiomyopathies
4. Fowl Cholera (P.mult)
5. Erysipelas
6. Aortic rupture in turkeys
What is omphalitis?
Infection of the yolk sac - a major cause of chick and poult mortality during the first week of life.
What is a common pathogen associated with omphalitis?
E. coli
What is considered the most important source of infection with omphalitis? What are two other sources?
Fecal comtamination of eggs most important. Others include ovarian infections or salpingitis
What does mortality rate depend on with omphalitis?
Specific strain of E. coli
What are the clinical signs of omphalitis?
reddened naval, chicks and poults often found dead, may have distended abdomen with wetness of the feathers covering the abdomen - "mushy chick disease"
What lesions are seen with omphalitis?
Reddening of navel tissues, yolk sac is markedly enlarged and filled with runny, dark yellow to green (green-brown) yolk material, malodorous, viscera is soft and friable to being covered with a fibrinous exudate (peritonitis)
How can omphalitis be prevented?
usually a hatchery problem, clean eggs prior to setting, clean incubator and water trays prior to setting, minimize contamination during incubation
A localized or systemic bacterial infection resulting in deposition of fibrinous exudate in teh thoracic and abdominal cavities and or the air sacs, joints, eyes, reproductive tract, meninges.
Colibacillosis
What is different between colibacillosis in mammals and poultry?
In mammals, usually a primary enteric disease. In poultry, most often a secondary event
What are some factors that increase host susceptibility to e. coli infections in poultry?
viral infections, bacterial infections, environmental, parasites, toxins
What are some clinical signs of colibacillosis?
peracute to acute septicemia (birds dead without signs of illness), respiratory signs (air sacculitis with deposition of fibrin), enteritis with excess mucus (diarrhea), panophthalmitis, synovitis and arthritis (fibrinous exudate in joints)
What is "white heart sac"
fibrinous pericarditis associated with colibacillosis
Are cardiomyopathies common causes of "sudden death" in chickens and turkeys?
No
What age group does "round heart disease" of chickens affect?
4-8 month old birds
What do the lungs, liver and kidneys look like with cardiomyopathies?
Lungs are edematous, liver and kidneys congested
What is the etiology of cardiomyopathies?
unknown
What age group is most affected by spontaneous cardiomyopay in turkeys?
2-3 week old poults
What age group broiler chickens are affected by ascites and and right ventricular failure?
4-7 weeks old
What is a major cause of ascites and right ventricular failure in broiler chickens?
Pulmonary hypertension possibly caused by hypoxemia (high altitude connection)
What is the causitive agent of Fowl Cholera?
P. multocida
What is an acute bacterial septicemia of domesticated and wild birds (waterfowl) associated with high morbidity and mortality?
Fowl cholera
What is an acute bacterial septicemia characterized by sudden deaths of individual older male turkeys?
Erysipelas caused by Erysipelothrix rhusiopathiae
T or F: Erysipelas is zoonotic to humans
True
What is the first sign of erysipelas in turkeys? Other signs?
Sudden deaths. Others include crusty lesions on head and swollen purplish turgid snoods, affected fertility in male, may see emaciation, weakness and anemia if endocarditis is present.
What is the tx of choice for Erysipelas?
Penicillin
What age group of turkeys is aortic rupture most common in?
7-24 weeks old
T or F:
Marek's disease often involves the bursa of Fabricius
False, it rarely does
What lesions are seen with aortic rupture in turkeys?
Marked pallor of head, skin and musculature; large blood clots in abdomen
T or F: Marek's Disease can cause cutaneous tumors
T, they have a distinct follicular orientation
What type of infiltrate is in the peripheral nerves in Marek's disease?
-neoplastic - lymphoblastic cells
-inflammatory cell infiltrates - small lymphocytes and plasma cells
What type of infiltrate is in the iris in Marek's disease?
neoplastic infiltrates
What type of infiltrate is in the visceral tumors in Marek's disease?
-pleomorphic neoplastic lymphocytes
-small to medium lymphocytes, lymphoblasts and primitive cells
-T-cell lymphoma