Evaluation of safety and efficacy of the bone marrow mesenchymal stem cell and gelatin-nano-hydroxyapatite combination in canine femoral defect repair.

Femoral shaft fracture is a common bone trauma in dogs. The limitation of mesenchymal stem cells in bone defect applications is that the cell suspension cannot be fixed to the bone defect site. In the study, our objective was to substantiate the combined application of canine bone marrow mesenchymal stem cells (cBMSCs) and gelatin-nano-hydroxyapatite (Gel-nHAP) and evaluate its therapeutic effect on bone defect diseases in dogs. Experiments were performed to evaluate the following: (1) the porosity of Gel-nHAP; (2) the adhesion of cBMSCs to Gel-nHAP; and (3) the effect of Gel-nHAP on cBMSC proliferation. The efficacy and safety of the combination of cBMSC and Gel-nHAP in the repair of femoral shaft defects were evaluated in animal experiments. The results showed that Gel-nHAP supported the attachment of cBMSCs and exhibited good biocompatibility. In the animal bone defect repair experiment, significant cortical bone growth was observed in the Gel-nHAP group at week 8 (p < 0.05) and in the cBMSCs-Gel-nHAP group at week 4 (p < 0.01). We demonstrated that Gel-nHAP could promote the repair of bone defects, and the effect of cBMSC-Gel-nHAP on the repair of bone defects was profound.

Isolation and Genetic Characterization of Emerging H3N2 Canine Influenza Virus in Guangdong Province, Southern China, 2018-2021.

H3N2 canine influenza virus (CIV) emerged in dogs in China or Korea around 2005 and was first reported in 2008. In 2015, H3N2 CIV was detected in the United States and caused a huge outbreak. To date, H3N2 CIV is continuously circulating in dog populations in China, Korea, and the United States. For continuous monitoring of H3N2 CIV in China, we collected 180 dog nasal swab samples and 196 cat nasal swabs from veterinary hospitals in Guangdong Province between 2018 and 2021. Six emerging H3N2 CIV strains were isolated. Following full genome sequencing and phylogenetic analyses, we found that A/canine/Guangdong/1-3/2018 and A/canine/Guangdong/1-3/2021 diverged from the reported sequences of the Chinese H3N2 CIV strains. Moreover, we found that these H3N2 CIV strains belong to the group that contains US and northern China CIV strains in 2017 and 2019 and dominate in the dog population until 2021.

Novel parvovirus in cats, China.

Parvovirus is a common element of the feline virus group and usually causes gastroenteritis and leukopenia in cats. In this study, we identified a novel protoparvovirus from the Chinese domestic cats, which is genetically similar to canine bufavirus (98.0%-99.8%), but sharing low amino acid identities in the viral structural proteins 2 (VP2) (36.1-37.2%) to the well-known canine parvovirus type 2 and feline panleukopenia virus. This virus was provisionally designated as feline bufavirus (FBuV). Screening of fecal samples revealed a prevalence of 7.4% (19/257) in domestic cats. Diarrhea was present in 52.6% (10/19) of cats positive for FBuV. However, statistical analysis showed no association between FBuV and clinical signs. VP2 gene of the 19 field FBuV was sequenced and phylogenetic analysis demonstrated that FBuV determined from China had a genetic diversity. This study will strengthen the understanding of the epidemiology and genetic diversity of bufavirus and provide a foundation for further studies.

Detection of Anaplasma platys in dogs using real-time loop-mediated isothermal amplification.

Anaplasma platys is a parasite of canine platelets that causes infectious cyclic thrombocytopenia. In this study, a novel real-time loop-mediated isothermal amplification (RT-LAMP) method was developed to detect A. platys. RT-LAMP primer sets were designed using a citrate synthase gene sequence and the assay was performed at 63 °C for 30 min. No cross-reactivity was observed with other Anaplasma or Ehrlichia spp. and the method exhibited a similar level of sensitivity in detecting the organism in 58 canine blood samples to that of a nested PCR. This RT-LAMP is a rapid and potentially cost-effective method of diagnosing A. platys infection in dogs.