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

Abstract

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.

Protein electrophoresis of non‐traditional species: A review

“…51 Thus far, these types of changes have been reported mostly in avian samples with infectious processes. [52][53][54][55][56][57][58][59][60] An abnormal electrophoretogram, therefore, can demonstrate the presence of an acute-phase response but is not supportive of the presence of any one specific disease. The exception is the presence of paraproteinemia, which is most commonly observed with lymphoproliferative diseases and some infectious diseases; the latter is primarily described in mammals.…”

“…113 EPH has been used as an adjunct tool in the diagnosis of infectious diseases, including chlamydiosis, aspergillosis, sarcocystosis, bornavirus infection, and mycobacteriosis. [52][53][54][55][56][57][58][59][60]64 In a study of African penguins with presumed or confirmed aspergillosis, a significant increase in alpha 2 globulins was associated with a specificity of 92% and a negative predictive value of 81%. In conjunction with increases in beta globulins and 3-hydroxybutyrate, the specificity was 98%.…”

Seeing beyond a Dilated Proventriculus: Diagnostic Tools for Proventricular Dilatation Disease in Psittacine Birds

“…Other changes such as leukocytosis and heterophilia have been inconsistently reported in some patients and may be associated with stress and secondary infections [20]. These findings have been supported by experimental studies [37]. Although the bloodwork of patients suffering from PDD might not indicate any definitive indication of the infection, it is advisable to perform hematology and clinical chemistry assessments of suspected patients to rule out differential diagnoses and to assess their general health.…”

“…Birds suffering from PDD show inconsistent changes in hematology and clinical chemistry assessments, and most are usually related to the catabolic state induced by gastrointestinal malabsorption, such as nonregenerative anemia and decreased total protein and albumin levels [ 20 , 37 ]. Additionally, elevated levels of muscle enzymes such as lactate dehydrogenase, creatine kinase and aspartate aminotransferase may be seen in infected birds.…”

“…Birds mount a detectable, although variable, humoral response to bornaviral infections. Therefore, serological methods such as Western blotting and enzyme-linked immunosorbent assay (ELISA) may be employed as tentative diagnostic tools in order to identify anti-PaBV antibodies [ 37 , 38 , 39 ]. Unfortunately, there is no available commercial ELISA for PDD to date, and these tests are usually performed by few laboratories.…”