Plasma protein, haematologic and blood chemistry changes in African grey parrots (Psittacus erithacus) experimentally infected with bornavirus

Bornaviruses are considered to be the causative agent of proventricular dilatation disease (PDD) in psittacine birds. In order to detect haematological and blood chemistry changes during the development of PDD and a possible correlation with clinical signs and the virological status, six African grey parrots (Psittacus erithacus) were experimentally infected with parrot bornavirus 4 (PaBV-4) by subcutaneous route. All six parrots developed clinical signs of varying extent and successful infection was confirmed in all the birds by seroconversion or detection of RNA of the PaBV-4 infection strain. Based on population-based and intra-individual reference ranges established during 12 months prior to experimental infection, only minor haematological changes were detected in individual birds after infection. Changes in blood chemistry were restricted to aspartate aminotransferase, creatine kinase, total protein, glucose and uric acid. Plasma protein electrophoresis revealed marked changes starting 10 weeks post infection characterized by an increase in the γ-globulin fraction and a gradual decrease to normal values during weeks 22–34. Indications of an acute-phase reaction at the initial stages of infection were not detected. While three birds suffered from clinical signs of PDD, which included weight loss and neurological disorders and died before development of haematological and plasma protein changes, recovery of clinical disease was paralleled in the remaining birds by an increase in γ-globulins and bornavirus-specific antibody titres.博尔纳病毒（Bornaviruses）被认为是鹦鹉类鸟类腺胃扩张症（proventricular dilatation disease, PDD）的致病原。为检测PDD发生过程中的血液学与血液生化指标变化，及其与临床症状、病毒学状态的潜在关联，研究通过皮下接种途径，对6只非洲灰鹦鹉（Psittacus erithacus）人工感染鹦鹉博尔纳病毒4型（parrot bornavirus 4, PaBV-4）。全部6只鹦鹉均出现程度不一的临床症状，且通过血清转换或检测PaBV-4感染株RNA，确认所有个体均成功感染。基于实验感染前12个月建立的群体水平与个体内参考区间，感染后仅在个别个体中检测到轻微血液学变化。血液生化指标的异常仅局限于天冬氨酸氨基转移酶、肌酸激酶、总蛋白、葡萄糖及尿酸。血浆蛋白电泳结果显示，感染后10周起出现显著变化，表现为γ-球蛋白组分升高，并在感染后22~34周逐渐回落至正常水平。未在感染初期检测到急性期反应的迹象。3只鹦鹉出现包括体重减轻与神经功能障碍在内的PDD临床症状，并在血液学与血浆蛋白变化出现前死亡；其余个体的临床症状缓解过程与γ-球蛋白水平升高、博尔纳病毒特异性抗体滴度上升同步发生。