Persistent infection with chicken anaemia virus and some effects of highly virulent infectious bursal disease virus infection on its persistency

Molecular and Pathological Analysis of Chicken Anemia Virus Isolated from Field Infection in Three Egyptian Provinces

“…In all PCR positive flocks, the thymus, liver, bursa of Fabricius and spleen collective samples were positive; this is probably because CAV targets erythroid and lymphoid progenitor cells in the bone marrow and thymus respectively (Adair, 2000). The obtained result revealed the detection of CAV DNA in 65% of tissues of investigated broiler chicken flocks and agreed with Mohamed (2010) Bülow and Schat (1997) reported CAV even in the presence of high neutralizing antibodies titers and Imai et al (1999) suggesting that the virus may persist in the presence of antibodies. In addition, live vaccines produced with CAV, contaminated eggs and cells may have played a role in the dissemination of CAV to chickens due to the previously undetected CAV infection in SPF flocks (Barrios et al, 2009).…”

Chicken infectious anaemia vaccinal strain persists in the spleen and thymus of young chicks and induces thymic lymphoid cell disorders

“…Hu et al (1993a) showed that persistent viraemia occurs in CIAV-infected birds in the absence of antibody production. The viral persistence of pathogenic CIAV was confirmed by Imai et al (1999), who suggested that CIAV can induce persistent infection in Figure 4. Analysis of relative expression of CD4 and CD8 molecules on thymocytes from CIAV-vaccinated and control groups at various times p.v.…”

“…It was previously reported that pathogenic CIAV was recovered from blood cells or lymphoid organs of infected birds at different days p.i. even in the presence of low or high viral-neutralizing antibodies (Yuasa et al, 1983;Imai et al, 1999). We can hypothesize that the incompetent immune system of the very young chicks favours a decrease of the CD4…”

TT virus infection: a novel virus-host relationship

“…This situation closely resembles the replication of the distantly related CAV in chickens. Anaemia, thrombocytopaenia and loss of T lymphocytes resulting from CAV replication in bone marrow and thymus are exacerbated by co-infection with other viruses, such as the immunosuppressive infections bursal disease virus [28]. Therefore, it is possible that TTV may have a similar adverse effect on bone marrow function, particularly in association with immune suppression.…”