Diagnosis of Chicken Anemia Virus Infections – Laboratory Tests
Laboratory tests for the diagnosis of CAV infections can be divided into those for antigen determination and those for antibody determination.
Isolation and identification of CAV
Viral isolation is usually done in embryonated specific pathogen free (SPF) eggs after yolk sac inoculation.
Virus isolation can also be attempted on MSCC-MSB1 cells culture, a lymphoblastoid cell line established from Marek’s Disease and Lymphoid Leukosis lymphomas. Growth is slow with low titers and at least 7-10 subcultures of inoculated cells are necessary for accurate end points for CAV infective titers. The virus can be isolated from different organs (liver, thymus, lung, heart, Bursa, muscle and bone marrow) but liver and buffy coat preparations are the preferred samples.
DNA-based virus detection
PCR
Polymerase chain reaction (PCR) utilizes specific primers which recognize the genome of the virus. The virus can be detected in the same target organs collected for virus isolation.
Antigen determination
Immunofluoresence
Immunofluoresence test with fluorescein-conjugated antibodies that attach to the virus when present, for example on MDCC-MSB1 infected cells culture
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Antibody determination
Virus neutralization test (VN)
Chicken serum is mixed with CAV growing on embryonated eggs or cell cultures. When the growth of the virus is inhibited, the antibodies in the serum are identified. Usually the ß method is used. This means that known virus is used at a constant concentration and is tested against varying two-fold dilutions of suspect serum. From the serial dilutions the antibody titre is calculated.
Enzyme linked Immuno Sorbent Assay (ELISA)
A competitive Elisa is used. The plates are covered with a complex of a monoclonal antibody and CAV. The complex is detected by an enzyme-labelled anti-γ-globulin. After adding an enzyme substrate, a resulting coloured product is measured. This test is useful to confirm the response to field infections and adequate antibody responses to vaccination.
The FlockChek* Chicken Anemia Virus Antibody Test Kit from IDEXX Laboratories is an ELISA test for detecting CAV antibodies in chicken serum.
FlockChek* Chicken Anemia Virus Antibody Test Kit
The FlockChek Chicken Anemia Virus Antibody Test Kit is an enzyme-linked immunosorbent assay (ELISA) designed to detect antibody to chicken anemia virus (CAV) in chicken serum.
Laboratory tests are required for a definitive diagnosis of CAV infection in chickens.
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