Chicken Anaemia Virus Disease Flashcards

Question	Answer		Article
What is Chicken anaemia virus disease also commonly known as?	Chicken anaemia Chicken infectious anaemia Blue wing disease		Link to Article
Which virus causes Chicken anaemia virus disease and what are it's properties?	Chicken anaemia virus (CAV): Non-enveloped icosahedral single stranded DNA (ssDNA) virus 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).		Link to Article
What family does the Chicken anaemia virus (CAV) belong to?	Circoviridae		Link to Article
What chemicals destroy the virus?	Hypochlorite and iodophor (formalin only reduces its infectivity).		Link to Article
How many proteins does CAV produce?	Three: Non-enveloped icosahedral single stranded DNA (ssDNA) virus VP1 (52kDA) - structural protein; intracellular form of the capsid protein VP2 (24 kDA) - found in small amounts in the purified virus VP3 (14 kDA) - involved in apoptosis (programmed and controlled cell death with no lysis of the cell. Causes apoptosis of infected stem cells in the bone marrow (BM). Sequential damage to BM inhibits the production of red blood cells (RBC), white blood cells (WBC), lymphoid tissue and platelets. Vaccines need to contain both VP1 and VP2 to be antigenic. Due to VP3 apoptotic properties it has the potential to be an anti-cancer agent.		Link to Article
Is Chicken anaemia virus disease considered to be a zoonosis?	No		Link to Article
What species of birds does the CAV infect?	Chickens (but can also affect quail). The disease severely affects 10-14 day old chicks.		Link to Article
What are the clinical signs of Chicken Anaemia Virus Disease?	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.		Link to Article
How is Chicken anaemia virus disease transmitted?	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.		Link to Article
How many serotypes of CAV are there?	One		Link to Article
How can CAV isolates be distinguished?	Restriction endonuclease analysis of amplified DNA.		Link to Article
What is the mortality rates within the flock?	5 to 10% (but can be as high as 60%). Mortality peaks during the third week of life		Link to Article
What is the distribution of CAV?	Worldwide - distribution including commercial poultry and specific pathogen free (SPF) flocks.		Link to Article
How do you diagnose Chicken anaemia virus disease?	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		Link to Article
What can be found on postmortem?	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		Link to Article
What is the treatment for Chicken anaemia virus disease?	There is no specific treatment for infected birds with this virus;culling is likely to be the most appropriate option for commercial flocks.		Link to Article
How is Chicken anaemia virus disease controlled?	Vaccination of breeding hens with both live attenuated and wild vaccines reduces the vertical transmission rate. Wild type vaccines are cheaper but can increase horizontal transmission rates and hidden reduction in production of older birds. At a farm level rigorous cleaning with hypochlorite, iodoform or formalin is recommended and biosecurity is important to try and erradicate on farm infections.		Link to Article