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).
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.
What are the clinical signs of Chicken Anaemia Virus Disease?
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.
Clinical signs include:
Pale; comb, wattle, eyelids, legs and carcass, *Anorexia, weight loss, stunting, and unthriftiness