Effects of chicken anaemia virus on experimental leukosis, induced by avian myelocytomatosis virus Mc29

Abstract

The effects of concomitant infection with chicken anaemia virus (CAV) on the incidence, clinical manifestation and mortality from leukosis, induced by the avian myelocytomatosis virus strain Mc29 were studied. Experimental one-day-old 15 I line White Leghorn chickens were inoculated simultaneously with Mc29 and CAV or with Mc29 alone and observed daily for clinical signs and mortality. Both groups of chickens inoculated with Mc29 virus strain alone or in combination with CAV deve­loped tumours and died within 57 days. Necropsy has been performed on all dead birds following the standard protocol. Organ samples from thymuses, spleens, bone marrow, and livers were collected and histopathologically investigated. Neoplasms detected included myelocytomas, nephroblastomas and hepatocellular carcinomas. In addition, 50% of the CAV/Mc29-inoculated chickens developed epithelial type thymomas. However, no such lesions were found in chickens infected with Mc29 alone. No significant differences in the clinical course of leukosis between the two experimental groups of chickens were observed. The results indicated that CAV infection did not affect substantially the incidence and mortality from avian leukosis, induced by myelocytomatosis virus strain Mc29, but contributed to greater variety of the induced tumours.