Recombinantly expressed virus-like particles (VLPs) of canine circovirus for development of an indirect ELISA.

Canine circovirus (CanineCV) is an emerging pathogen in domestic dogs, detected in multiple countries in association with varying clinical and pathological presentations including diarrhoea, vasculitis, granulomatous inflammation, and respiratory signs. Understanding the pathology of CanineCV is confounded by the fact that it has been detected in asymptomatic dogs as well as in diseased dogs concurrently infected with known pathogens. Recombinantly expressed self-assembling Virus-like particles (VLPs) lack viral genomic material but imitate the capsid surface conformations of wild type virion, allowing arrays of biological applications including subunit vaccine development and immunodiagnostics. In this study, full length CanineCV capsid gene was expressed in Escherichia coli followed by two-step purification process to yield soluble capsid protein in high concentration. Transmission electron microscopy (TEM) confirmed the capsid antigen self-assembled into 17-20 nm VLPs in glutathione S-transferase (GST) buffer, later utilised to develop an indirect enzyme-linked immunosorbent assay (iELISA). The respective sensitivity and specificity of the proposed iELISA were 94.10% and 88.40% compared with those obtained from Western blot. The mean OD450 value for western blot positive samples was 1.22 (range 0.12-3.39) and negative samples was 0.21 (range 0.07-0.41). An optimal OD450 cut-off of 0.35 was determined by ROC curve analysis. Median inter-assay and intra-assay validation revealed that the iELISA test results were reproducible with coefficients of variation 7.70 (range 5.6-11.9) and 4.21 (range 1.2-7.4). Our results demonstrated that VLP-based iELISA is a highly sensitive method for serological diagnosis of CanineCV infections in dogs, suitable for large-scale epidemiological studies.

A Multicentre Epidemiologic Study of Sudden and Unexpected Death in Adult Cats and Dogs in Australia.

Sudden and unexpected death (SUD) is a common reason for animals to undergo post-mortem examination. There is limited literature examining the causes of SUD in cats and dogs, and no research specific to Australia. The purpose of this study was to investigate the epidemiology and pathology of SUD in cats and dogs in a multicentric study across Australia. Retrospective post-mortem reports of SUD in cats and dogs were obtained from four veterinary schools in Australia distributed across four states. The frequency of SUD between institutes ranged from 2.1% to 6.5%. Dogs composed the majority of the study population (76%), and males outnumbered females, particularly in the feline subpopulation. After necropsy, 37% of SUD remained cause unknown, the largest category in both cats and dogs. When cause was identified, cardiovascular disease was most common in both species, followed by gastrointestinal disease in dogs, and trauma in cats. In dogs, multinomial logistic regression identified age as a risk factor significantly associated with the four largest categories of SUD. This study identified causes of SUD in Australian cats and dogs, including novel causes not previously reported. Further, this study revealed a higher rate of unsolved SUD in Australia than can be found in the literature from other countries.