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Chicken Anaemia Virus Disease Flashcards (view source)
Revision as of 09:12, 25 August 2011
, 09:12, 25 August 2011no edit summary
<FlashCard questions="6">
<FlashCard questions="14">
|q1=?
|q1=What is Chicken anaemia virus disease (CAV) also commonly known as?
|a1=
|a1=
|l1= #
*Chicken anaemia
|q2= ?
*Chicken infectious anaemia
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*Blue wing disease
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|l1=Chicken Anaemia Virus Disease#Introduction
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|q2=What are the virus properties?
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|a2=
|l3= #
*Non-enveloped icosahedral single stranded DNA (ssDNA) virus
|q4= ?
*23-25 nm diameter
*Small circular genome of negative sense
*Very hardy and resistant to high temperatures, acidic pH (pH3), chloroform and commercial disinfectants.
*Morphologically and antigenically different to other circoviruses such as ''Porcine circovirus'' (PCV) and ''Psittacine beak and feather disease virus'' (PBFDV).
|l2=Chicken Anaemia Virus Disease#Introduction
|q3=What family does CAV belong to?
|a3=Circoviridae
|l3=Chicken Anaemia Virus Disease#Introduction
|q4=What chemicals destroy the virus?
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|a4=
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*Hypochlorite and iodophor (formalin only reduces its infectivity).
|l4=Chicken Anaemia Virus Disease#Introduction
|q5=Is Chicken anaemia virus disease considered to be a zoonosis?
|a5=No
|l5=Chicken Anaemia Virus Disease#Introduction
|q6=What species of birds does the CAV infect?
|a6=
*Chickens (but can also affect quail). The disease severely affects 10-14 day old chicks.
|l6=Chicken Anaemia Virus Disease#Signalment
|q7=What are the clinical signs of Chicken Anaemia Virus Disease?
|a7=
Clinical signs include:
*Pale; comb, wattle, eyelids, legs and carcass,
*Anorexia, weight loss, stunting, and unthriftiness
*Cyanosis, petechiation and ecchymoses,
*Weakness, lethargy and sudden death.
Neurological signs include:
*Dullness
*Depression
*Paresis
Clinical signs are dependent on the age of the bird. Chicks develop clinical signs within two weeks of hatching if infected via vertical transmission. Chicks older than 14 days old do not show any clinical signs if infected via horizontal transmission.
|l7=Chicken Anaemia Virus Disease#Clinical Signs
|q8=How is Chicken anaemia virus disease transmitted?
|a8=
*Horizontally through fomites and faecal-orally 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.
|l8=Chicken Anaemia Virus Disease#Epidemiology
|q9=What is the mortality rates within the flock?
|a9=
*5 to 10% (but can be as high as 60%).
*Mortality peaks during the third week of life
|l9=Chicken Anaemia Virus Disease#Epidemiology
|q10=What is the distribution of CAV?
|a10=Worldwide - distribution including commercial poultry and specific pathogen free (SPF) flocks.
|l10=Chicken Anaemia Virus Disease#Distribution
|q11=How do you diagnose Chicken anaemia virus disease?
|a11=
*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 developed: immunoperoxidase staining, ELISA, PCR, indirect immunofluorescence
|l11=Chicken Anaemia Virus Disease#Diagnosis
|q12=What can be found on postmortem?
|a12=
*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
|l12=Chicken Anaemia Virus Disease#Diagnosis
|q13=What is the treatment for Chicken anaemia virus disease?
|a13=
There is no specific treatment for infected birds with this virus; culling is likely to be the most appropriate option for commercial flocks.
|l13=Chicken Anaemia Virus Disease#Treatment
|q14=How is Chicken anaemia virus disease controlled?
|a14=
Vaccination of breeding hens with both live attenuated and wild vaccines reduces the vertical transmission rate.
At a farm level rigorous cleaning with hypochlorite, iodoform or formalin is recommended and biosecurity is important to try and erradicate on farm infections.
|l14=Chicken Anaemia Virus Disease#Control
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