Chicken hepatomegaly and splenomegaly associated with novel subgroup J avian leukosis virus infection

BACKGROUND: Subgroup J avian leukosis virus (ALV-J) is an oncovirus which can induce multiple types of tumors in chicken. In this report, we found novel ALV-J infection is closely associated with serious hepatomegaly and splenomegaly in chicken. CASE PRESENTATION: The layer chickens from six flocks in Jiangsu province, China, showed serious hemoperitoneum, hepatomegaly and splenomegaly. Histopathological results indicated focal lymphocytic infiltration, cell edema and congestion in the liver, atrophy and depletion of lymphocyte in the spleen. Tumor cells were not detected in all the organs. avian hepatitis E virus (aHEV), which is thought to be the cause of a very similar disease, big liver and spleen disease (BLS), was not detected. Other viruses causing tumors or liver damage including Marek’s disease virus (MDV), reticuloendotheliosis virus (REV), fowl adenovirus (FAdV) and chicken infectious anemia virus (CIAV) were also proved negative by either PCR or RT-PCR. However, we did detect ALV-J in those chickens using PCR. Only novel ALV-J strains were efficiently isolated from these chicken livers. CONCLUSIONS: This is the first report that chicken hepatomegaly and splenomegaly disease was closely associated with novel ALV-J, highlighting the importance of ALV-J eradication program in China. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12917-022-03139-1.