Naturally Occurring Co-infection of Avian Leukosis Virus (subgroups A-E) and Reticuloendotheliosis Virus in Green Peafowls (Pavo muticus)

ABSTRACT Most of the neoplastic diseases affecting poultry have a viral etiology, such as Marek’s disease, avian leukosis/sarcoma and reticuloendotheliosis. In the present paper, histopathology and molecular methods were performed, in addition of necropsy and gross morphology evaluation, for the differential diagnosis of these diseases in two green peafowls (Pavo muticus). The affected birds showed non-specific signs, such as depression, anorexia, and diarrhea. At necropsy, diffuse enlargement by several times the normal size of the liver and the spleen was observed. In one of the birds, the liver presented white to grayish discoloration was present, and focal and nodular growths in the other bird. Grossly, the other visceral organs and the peripheral nerves were normal. Microscopically, most of the tumor cells were large and uniform with pleomorphic nuclei. The PCR analysis for Marek’s disease virus (MDV), avian leukosis virus (ALV), lymphoproliferative disease virus (LPDV), and reticuloendotheliosis virus (REV)based on their specific sequences showed the presence of ALV subgroups A-E and REV. According to these results, definitive diagnosis was co-infection of ALV and REV in naturally-infected green peafowls.

摘要 危害禽类的肿瘤性疾病大多具有病毒性病因，例如马立克氏病（Marek’s disease）、禽白血病/肉瘤病以及网状内皮组织增殖症。本研究通过尸检、大体形态学评估，结合组织病理学与分子生物学方法，对2只绿孔雀（Pavo muticus）的上述疾病开展鉴别诊断。患病孔雀表现出精神沉郁、食欲减退、腹泻等非特异性临床症状。尸检可见肝脏与脾脏较正常体积弥漫性肿大数倍：其中1只孔雀的肝脏出现灰白色变色，另1只则可见局灶性结节状增生。大体观察下，其余内脏器官及外周神经均无异常。镜下观察可见多数肿瘤细胞体积较大、形态均一，细胞核具有多形性。针对马立克氏病病毒（MDV）、禽白血病病毒（ALV）、淋巴增生性疾病病毒（LPDV）及网状内皮组织增殖症病毒（REV）的特异性基因序列进行聚合酶链式反应（PCR）检测，结果显示样本中存在A-E亚型禽白血病病毒与网状内皮组织增殖症病毒。综合上述检测结果，确诊该2只自然感染的绿孔雀为禽白血病病毒与网状内皮组织增殖症病毒混合感染。