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Background: Canine coronavirus (CCoV), canine rotavirus (CRV), canine parvovirus (CPV), and canine distemper virus (CDV) cause gastroenteritis in dogs, and co-infections of these pathogens are common in China. In particular, CCoV and CRV are confirmed to have important zoonotic potential and cause public health issues. It is difficult to diagnose these diseases based only on clinical manifestations and pathological damage. Methods: In this study, four pairs of specific primers and probes targeting the CCoV M, CRV VP7, CPV VP2, and CDV N genes were designed. The reaction conditions, including the primer and probe concentrations, annealing temperatures, and reaction cycles, were optimized for the development of a quadruplex RT-qPCR for the detection of CCoV, CRV, CPV, and CDV. The assay was used to test 1028 clinical samples to validate its application. Results: A quadruplex RT-qPCR was successfully established for the differential detection of CCoV, CRV, CPV, and CDV, with good specificity, high sensitivity, and excellent repeatability. The assay could specifically detect CCoV, CRV, CPV, and CDV without cross-reactivity with the other canine viruses tested. It showed high sensitivity with limits of detection (LOD) of 1.1 × 102 copies/reaction for all four plasmid constructs. It showed excellent repeatability, with 0.05–0.90% intra-assay variation and 0.02–0.94% inter-assay variation. The 1028 clinical samples were tested using the quadruplex RT-qPCR and a reported reference RT-qPCR. The positivity rates of CCoV, CRV, CPV, and CDV were 9.53%, 0.97%, 25.68%, and 5.06% using the developed assay, and 9.05%, 0.88%, 25.68%, and 4.86% using the reference assay, with agreements higher than 99.32%. Conclusion: The results indicated that a rapid and accurate quadruplex RT-qPCR was developed for the detection and differentiation of CCoV, CRV, CPV, and CDV. [ABSTRACT FROM AUTHOR]

Background: The red panda has been classified as an endangered species due to the decreased number in the world and disease is considered as a great threat to the health and survival of the cubs in captivity. Results: This study analyzed 32 red panda cub mortalities (15 females and 17 males, age less than two months) through gross necropsy, microbiological examination, and histopathological observation at the Chengdu Research Base of Giant Panda Breeding, China, during 2014–2020. The results showed that screenings for canine distemper virus, canine parvovirus, rotavirus and parasite infection were all negative, however bacteria such as Klebsiella pneumoniae, Proteus mirabilis, Escherichia coli, Enterococcus faecalis, Pseudomonas were isolated from the tissue samples of some cubs. The major causes of death were respiratory (43.75%) and digestive system disease (28.13%), followed by cardiovascular disease (12.5%) and neonatal stillbirths (9.38%). Renal system diseases and trauma were also detected, at lower incidence (one case for each). The mortality rate within 15 days of birth was 68.75% and gradually decreased with age, there was no significant difference in gender. Conclusion: This study can provide a scientific basis for the analysis of the cause of death among red panda cubs in captivity, so as to improve the survival rate, help build the captive population and further the ex-situ conservation management of this endangered species. Additionally, our research may also provide insights into the in-situ conservation of wild red pandas by identifying emerging disease threats within the wild population and potential treatment for rescued individuals. [ABSTRACT FROM AUTHOR]