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==Introduction==

==Introduction==

Chicken anaemia virus disease is commonly referred to as chicken anaemia, chicken infectious anaemia and blue wing disease.  It is caused by the '''''chicken anaemia virus''''' (CAV), which is a non-enveloped icosahedral '''single stranded DNA (ssDNA) virus'''.  CAV  is 23-25 nm diameter and is part of the Circoviridae, composing of a small circular genome of negative sense. The virus iis '''difficult to eradicate''' as it is '''very hardy and resistant to high temperatures, acidic pH (pH3), chloroform''' and '''commercial disinfectants'''.  CAV can be '''destroyed with hypochlorite and iodophor''' and '''formalin can reduce its infectivity'''.  It  is also morphologically and antigenically different to other circoviruses such as [[Porcine Circoviruses| ''porcine circovirus'' (PCV)]] and [[Psittacine Beak and Feather Disease|  ''psittacine beak and feather disease virus'' (PBFDV)]].   

Chicken anaemia virus disease is commonly referred to as chicken anaemia, chicken infectious anaemia and blue wing disease.  It is caused by the '''''chicken anaemia virus''''' (CAV), which is a non-enveloped icosahedral '''single stranded DNA (ssDNA) virus'''.  CAV  is 23-25 nm diameter and is part of the Circoviridae, composing of a small circular genome of negative sense. The virus iis '''difficult to eradicate''' as it is '''very hardy and resistant to high temperatures, acidic pH (pH3), chloroform''' and '''commercial disinfectants'''.  CAV can be '''destroyed with hypochlorite and iodophor''' and '''formalin can reduce its infectivity'''.  It  is also morphologically and antigenically different to other circoviruses such as [[Porcine Circoviruses| ''Porcine circovirus'' (PCV)]] and [[Psittacine Beak and Feather Disease|  ''Psittacine beak and feather disease virus'' (PBFDV)]].   

CAV produces three types of proteins of VP1 (52kDA), VP2 (24 kDA) and VP3 (14 kDA) kDa .  Structural protein VP1 is the intracellular form of the capsid protein and VP2 is found in small amounts in the purified virus. Vaccines need to contain both of these to be antigenic.  '''VP3''' is involved in '''apoptosis''' which involves the '''programmed and controlled death of a cell'''.  This process does not involve the lysis of the cell and therefore limits damage to surrounding cells and tissues. It also initiates pathogenicity and '''apoptosis of infected stem cells in the bone marrow (BM)''', resulting in damage to the BM.  As a result the virus '''inhibits the production of red blood cells (RBC), white blood cells (WBC) and platelets.  Lymphoid tissues are also affected'''.  Due to its apoptotic properties VP3 has the potential to be an anti-cancer agent.  It is '''not considered a zoonosis'''.

CAV produces '''three types of proteins''' of '''VP1''' (52kDA), '''VP2''' (24 kDA) and '''VP3''' (14 kDA) kDa .  '''Structural protein VP1'' is the intracellular form of the capsid protein and '''VP2''' is found in small amounts in the '''purified virus'''. Vaccines need to contain both of these to be antigenic.  '''VP3''' is involved in '''apoptosis''' which involves the '''programmed and controlled death of a cell'''.  This process does not involve the lysis of the cell and therefore limits damage to surrounding cells and tissues. It also initiates pathogenicity and '''apoptosis of infected stem cells in the bone marrow (BM)''', resulting in damage to the BM.  As a result the virus '''inhibits the production of red blood cells (RBC), white blood cells (WBC) and platelets.  Lymphoid tissues are also affected'''.  Due to its apoptotic properties VP3 has the potential to be an anti-cancer agent.  It is '''not considered a zoonosis'''.

CAV is difficult to grow but can be grown in chickens, embryonated eggs and in cell culture. The most commonly used cell line is MDCC-MSB1 (a Marek’s disease transformed chicken lymphocyte cell line) <ref name=" Yuasa, 1983">Yuasa, N. (1983). '''Propagation and infectivity titration of the Gifu-1 strain of chicken anemia agent in a cell line (MDCC-MSB1) derived from Marek's disease lymphoma'''. ''National Institute of Animal Health Quarterly'', Japan, 23(1):13-20; 18 ref. </ref>, <ref name=" Goryo et al., 1987"> Goryo, M., Suwa, T., Matsumoto, S., Umemura, T., Itakura, C. (1987). '''Serial propagation and purification of chicken anaemia agent in MDCC-MSB1 cell line'''. ''Avian Pathology, 16(1):149-163; [7 fig.]; 18 ref''. </ref>. Virus production in this way may lead to the potential for Marek’s disease virus contamination of vaccines.

CAV is difficult to grow but can be grown in chickens, embryonated eggs and in cell culture. The most commonly used cell line is MDCC-MSB1 (a Marek’s disease transformed chicken lymphocyte cell line) <ref name=" Yuasa, 1983">Yuasa, N. (1983). '''Propagation and infectivity titration of the Gifu-1 strain of chicken anemia agent in a cell line (MDCC-MSB1) derived from Marek's disease lymphoma'''. ''National Institute of Animal Health Quarterly'', Japan, 23(1):13-20; 18 ref. </ref>, <ref name=" Goryo et al., 1987"> Goryo, M., Suwa, T., Matsumoto, S., Umemura, T., Itakura, C. (1987). '''Serial propagation and purification of chicken anaemia agent in MDCC-MSB1 cell line'''. ''Avian Pathology, 16(1):149-163; [7 fig.]; 18 ref''. </ref>. Virus production in this way may lead to the potential for Marek’s disease virus contamination of vaccines.