Although many vector-borne agents are potential zoonoses and cause substantial morbidity and mortality in dogs worldwide, there are limited data on these organisms in dogs of China. Quantitative PCRs for vector-borne agents were performed to investigate their prevalences in convenience whole blood samples obtained from 1114 dogs from 21 veterinary clinics and a commercial dog breeding facility in ten provinces of China. In addition, the PCRs were performed on 146 Rhipicephalus sanguineus senso lato and 37 Linognathus setosus collected from dogs in the commercial dog breeding facility. DNAs of Babesia gibsoni and B. vogeli (1.2 %), Ehrlichia canis (1.3 %), Hepatozoon canis (1.8 %) and Theileria orientalis (0.1 %) or a closely related organism were detected in the bloods of the dogs studied, and Babesia vogeli (3.4 %) and Ehrlichia canis (4.1 %) in R. sanguineus senso lato. The qPCRs for Anaplasma spp., Dirofilaria immitis and Leishmania spp. were negative for all blood samples, ticks and lice. At least one vector-borne agent was found in dogs from 5 of the 10 provinces investigated in this study. Overall, 4.4 % (49/1117) of the dogs studied were positive for at least one vector-borne agent with the prevalence being highest in the commercial breeding colony (24/97; 24.7 %). Our study confirms that B. vogeli, B. gibsoni, H. canis, and E. canis occur in China. Also, we present evidence that T. orientalis or a closely related organism can infect dogs.

Chlamydia suis is an important, globally distributed, highly prevalent and diverse obligate intracellular pathogen infecting pigs. To investigate the prevalence and genetic diversity of C. suis in China, 2,137 nasal, conjunctival, and rectal swabs as well as whole blood and lung samples of pigs were collected in 19 regions from ten provinces of China in this study. We report an overall positivity of 62.4% (1,334/2,137) of C. suis following screening by Chlamydia spp. 23S rRNA-based FRET-PCR and high-resolution melting curve analysis and confirmatory sequencing. For C. suis-positive samples, 33.3 % of whole blood and 62.5% of rectal swabs were found to be positive for the C. suis tetR(C) gene, while 13.3% of whole blood and 87.0% of rectal swabs were positive for the C. suis tet(C) gene. Phylogenetic comparison of partial C. suis ompA gene sequences revealed significant genetic diversity in the C. suis strains. This genetic diversity was confirmed by C. suis-specific multilocus sequence typing (MLST), which identified 26 novel sequence types among 27 examined strains. Tanglegrams based on MLST and ompA sequences provided evidence of C. suis recombination amongst the strains analyzed. Genetically highly diverse C. suis strains are exceedingly prevalent in pigs. As it stands, the potential pathogenic effect of C. suis on pig health and production of C. suis remains unclear and will be the subject of further investigations. Further study is also required to address the transmission of C. suis between pigs and the risk of 'spill-over' and 'spill-back' of infections to wild animals and humans.

Hepatitis E is a disease of major public-health concern mainly in developing countries. Although molecular and sero-epidemiological investigations of HEV have been performed in many provinces in China, the epidemiological data from Yunnan Province are limited and genotypes are not be fully characterized. In this study the prevalence and characteristics of hepatitis E virus (HEV) detected in pigs from Yunnan province, China was evaluated. A total of 13 out of 187 pig fecal samples collected in 2011 revealed HEV positive results; likewise, 7 out of 69 samples collected in 2012 exhibited positive results. These findings indicated a total prevalence of 7.8% (20/256). Phylogenetic and molecular evolutionary analysis results revealed that nine strains were found in the samples obtained in 2011, in which 87.1% to 99.4% nucleotide sequence identity was shared among these strains; and 77.0% to 81.9%, 52.2% to 53.6%, 77.0% to 88.2% and 77.9% to 96.8% nucleotide sequence identities were shared with strains representing genotypes 1, 2, 3, and 4. Five strains were detected in the samples obtained in 2012, in which 94.2% to 99.3% nucleotide sequence identity was shared among the strains, and 81.0% to 82.5%, 81.8% to 83.2%, 81.0% to 92.7% and 81.0% to 97.8% nucleotide sequence identities were shared with strains representing the genotypes 1, 2, 3, and 4. Analysis of fourteen detected HEV strains revealed that three of them were subtype 4d, two were subtype 4b; the nine remaining isolated strains were subtype 4 h. These results indicated that the prevalence of HEV in the swine herds of Yunnan was quite high, additional public-health concerns should focus on pork safety.

Porcine pseudorabies virus (PRV) causes astrocyte injury through oxidative stress, inflammatory responses, and metabolic dysfunction. Rhynchophylline (RHY) possesses antioxidant and anti-inflammatory properties, but its protective effects against PRV infection remain unclear. Using PRV-infected C8-D1A cells, we evaluated the antiviral and cytoprotective effects of RHY. At a non-toxic concentration of 5 μM, RHY significantly inhibited PRV replication, reduced intracellular reactive oxygen species, and alleviated oxidative stress by decreasing xanthine oxidase (XOD), myeloperoxidase (MPO), malondialdehyde (MDA), and nitric oxide (NO) levels while restoring superoxide dismutase (SOD) activity. RHY also modulated PRV-induced inflammatory imbalance by suppressing interleukin (IL)-6 and IL-8 and enhancing IL-4 and IL-10 expression. Metabolomic profiling revealed that PRV infection disrupted cellular metabolism, particularly pathways related to unsaturated fatty acid biosynthesis and the tricarboxylic acid (TCA) cycle, which were largely restored by RHY treatment. These findings indicate that RHY exerts antiviral, anti-inflammatory, and antioxidant effects by correcting PRV-induced metabolic disturbances in vitro .

Background: Pseudorabies virus (PRV), a zoonotic swine alphaherpesvirus, poses a severe threat to global pig production and public health. Aim: This study aimed to investigate the regulatory role of the RASSF6 gene in PRV-infected porcine alveolar macrophages (3D4/21). Methods: We established stable cellular models of RASSF6 overexpression (verified by qRT-PCR and immunofluorescence using an empty vector control) and siRNA-mediated RASSF6 silencing (verified by qRT-PCR) to investigate the role of RASSF6. Using these models, we assessed viral replication (quantified by qRT-PCR/TCID50) and apoptosis (analyzed by flow cytometry with Annexin V/PI staining and ELISA). Results: RASSF6 expression was significantly upregulated after PRV infection. RASSF6 overexpression inhibited 3D4/21 cell proliferation and PRV replication and promoted apoptosis through Bax and Caspase-3/9 activation. RASSF6 silencing promoted cell proliferation and viral replication and inhibited apoptosis. Conclusion: RASSF6 is a critical host defense factor against PRV infection in porcine alveolar macrophages. RASSF6 upregulation restricts viral replication by inducing apoptosis via Bax/caspase-3/9 activation and simultaneously suppressing cell proliferation. Conversely, RASSF6 silencing creates a permissive environment for PRV propagation by inhibiting apoptosis and enhancing cell survival. These findings reveal RASSF6-mediated apoptosis as a novel antiviral mechanism and highlight its potential as a therapeutic target for controlling PRV pathogenesis.