[2] CAV is a non-enveloped icosahedral single stranded DNA virus,[3] which causes bone marrow atrophy, anemia, and severe immunosuppression.

Clinical signs of CAV infection are predominantly found in young chicks due to vertical transmission from the breeder hens whose maternal antibodies have not yet formed following exposure.

Clinical disease is rare today because of the widespread practice of vaccinating breeders, but the subclinical form of the disease—which normally affects birds more than two weeks of age following horizontal transmission of the virus via the fecal–oral route—is ubiquitous.

[5] Signs include a pale comb, wattle, eyelids, legs and carcass, anorexia, weakness, stunting, unthriftiness, weight loss, cyanosis, petechiation and ecchymoses, lethargy, and sudden death.

In older chickens, an infection with no apparent symptoms may cause reduced growth rates due to a poor feed conversion ratio.