Chicken anaemia virus affects the development of the blood cells and the immune system in young chickens.

Affected chickens are pale (anaemic), stunted and show increased mortality between 10 to 24 days of age. Gangrenous dermatitis “blue wing” may be seen. On post mortem the characteristic signs include a pale carcass, atrophied thymus and bone marrow as well as muscular haemorrhage. Development of age resistance occurs. Subclinical infection may affect broiler performance. The chicken is infected via the infected egg and the virus spreads easily among chickens. Adult chickens do not show any signs if they become infected with the virus.

The vaccine is given to pullets prior to lay, to ensure that maternal antibodies are present.