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Chicken Anaemia Virus Disease Flashcards (view source)
Revision as of 11:20, 29 June 2011
, 11:20, 29 June 2011no edit summary
*Chicks older than 14 days old do not show any clinical signs if infected via horizontal transmission.
*Chicks older than 14 days old do not show any clinical signs if infected via horizontal transmission.
|l8=Chicken Anaemia Virus Disease#Clinical Signs
|l8=Chicken Anaemia Virus Disease#Clinical Signs
|q9=What species of birds does the CAV infect?
|q9=How is ''Chicken anaemia virus disease transmitted?
|a9=
|a9=
*Chickens (but can also affect quail).
*Horizontally through fomites and faecal-oral as the virus is excreted by a small number of vertically infected hatch mates. This occurs in older chickens that lack maternal derived antibodies.
*Vertically as chicks hatch from infected layers of naive flocks over a period of 3 to 6 weeks. After this period the breeder layers develop sufficient CAV antibodies to stop the transmission of the virus to the egg. Clinical signs are seen in 10-14 day old chicks.
|l9=Chicken Anaemia Virus Disease#Signalment
|l9=Chicken Anaemia Virus Disease#Epidemiology
|q10=What species of birds does the CAV infect?
|q10=How many serotypes of CAV are there?
|a10=
|a10=One
*Chickens (but can also affect quail).
|l10=Chicken Anaemia Virus Disease#Epidemiology
|q11=How can CAV isolates be distinguished?|a11=Restriction endonuclease analysis of amplified DNA.
|l10=Chicken Anaemia Virus Disease#Signalment
|l11=Chicken Anaemia Virus Disease#Epidemiology
|q12=What is the mortality rates within the flock?
|a12=
*5 to 10% (but can be as high as 60%).
*Mortality peaks during the third week of life
|l12=Chicken Anaemia Virus Disease#Epidemiology
|q13=What is the distribution of CAV?
|a13=Worldwide - distribution including commercial poultry and specific pathogen free (SPF) flocks.
|l13=Chicken Anaemia Virus Disease#Distribution
|q14=How do you diagnose ''Chicken anaemia virus disease''?
|a14=
*Clinical signs
*Decreases in haematocrit from normal ranges (32-37.5%) to below 27%
*Increases in the amount of immature blood cells
*Virus isolation (confirms diagnosis) - but growth of CAV in cell cultures can be difficult.
Levels of infection can be estimated by the detection of raising antibody titres.
Many diagnostic tests have been develop:
*Immunoperoxidase staining
*ELISA
*PCR
*Dot blot hybridisation
*Indirect immunofluorescence
|l14=Chicken Anaemia Virus Disease#Diagnosis
Post mortem findings include:
*severe atrophy of the lymphoid organs. The thymus, bursa of Fabricius, and to a lesser extent the spleen are all affected by a depletion of lymphocytes and sequential hyperplasia of reticular cells. Common finding include haemorrhages throughout the skeletal muscle and subcutaneous tissue and pale watery bone marrow. Severe aplasia of the bone marrow occurs and haematopoietic cells are replaced with adipose tissue, giving the bone marrow its watery texture and characteristic change in colour from red to yellow.
|l14=Chicken Anaemia Virus Disease#Epidemiology
|q15=What can be found on postmortem?
|a15=
*Severe atrophy of the lymphoid organs (thymus, bursa of Fabricius, and to a lesser extent the spleen). All become depleted of lymphocytes and reticular cells become hyperplastic.
*Haemorrhages throughout the skeletal muscle and subcutaneous tissue
*Pale watery yellow bone marrow - due to severe aplasia of the BM and the haematopoietic cells being replaced with adipose tissue
|l15=Chicken Anaemia Virus Disease#Diagnosis
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