Cause

Infectious anaemia is caused by a very resistant small virus known as CAV (Chicken Anaemia Virus).

Transmission

The major mode of transmission of infectious anaemia is through infected breeder hens (vertical). Horizontal transmission can be through bird-to-bird contact, infected equipment and clothing, etc.

Clinical signs and lesions

CAV causes a syndrome in young chicks up to approximately 3 weeks of age. Adult birds may get infected but will not develop clinical signs. The disease is characterized by increased mortality and anaemia associated with atrophy of the haematopoietic tissues in the bone marrow. Subcutaneous and intramuscular haemorrhages can be found accompanied with atrophy of the lymphoid system. Affected birds may show focal skin lesions (also known as blue-wing disease). Mortality rates vary from 20% to 70%. Affected flocks will show poor growth resulting in significant economic losses.

Diagnosis

The diagnosis can be based on the clinical signs and pathological findings in affected birds. Blood serum testing for specific CAV antibodies can be carried out (IFT, VN, ELISA). Virus isolation is also possible but it is time-consuming and expensive.

Treatment and control

No treatment is available for infectious anaemia. Maternally derived antibodies can offer protection by vaccinating breeders hence still is the best approach to successful CAV control.