Chicken Anaemia

calendar icon 22 March 2019
clock icon 3 minute read


A viral disease of chickens caused by Chicken Anaemia Virus or CAV. Prior to confirmation that it is in fact a virus it was known as Chicken Anaemia Agent or CAA.

Mortality is typically 5-10% but may be up to 60% if there are predisposing factors present such as intercurrent disease (Aspergillosis, Gumboro, Inclusion body heptatitis etc.) or poor management (e.g. poor litter quality).

Transmission is usually vertical during sero-conversion of a flock in lay, lateral transmission may result in poor productivity in broilers.

The virus is resistant to pH 2, ether, chloroform, heat (70°C for 1 hour, 80°C for 5 minutes) and many disinfectants even for 2 hours at 37°C. Hypochlorite appears most effective in vitro.


  • Poor growth.
  • Pale birds.
  • Sudden rise in mortality (usually at 13-16 days of age).
  • No clinical signs or effect on egg production or fertility in parent flock during sero-conversion.

Post-mortem lesions

  • Pale bone marrow.
  • PCV of 5-15% (normal 27-36%).
  • Atrophy of thymus and bursa.
  • Discoloured liver and kidney.
  • Gangrenous dermatitis on feet, legs wings or neck.
  • Acute mycotic pneumonia.


Gross lesions, demonstration of ongoing sero-conversion in parent flock, virus may be isolated in lymphoblastoid cell line (MDCC-MSB1).


Good hygiene and management, and control of other diseases as appropriate, may be beneficial. If gangrenous dermatitis is a problem then periodic medication may be required.


Live vaccines are available for parents, their degree of attenuation is variable. They should be used at least 6 weeks prior to collecting eggs for incubation. Their use may be restricted to those flocks that have not sero-converted by, say, 15 weeks.

Immunity: there is a good response to field challenge (in birds over 4 weeks of age) and to attenuated live vaccines.

Serology: antibodies develop 3-6 weeks after infection, and may be detected by SN, Elisa, or IFA.

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