First Clinical Case of Equine Parvovirus-Hepatitis-Related Theiler's Disease in Asia.

Equine parvovirus-hepatitis (EqPV-H) is a newly identified etiologic agent of Theiler's disease (TD). We present a case of EqPV-H-related fulminant hepatitis in a 14-year-old thoroughbred mare in Korea. The mare had acute hepatopathy and gastrointestinal symptoms, with abnormal liver-related blood parameters. The horse was born in the USA and imported to Korea in 2017, with no history of administration of equine biological products after entry into Korea. The horse was diagnosed with EqPV-H-associated hepatitis after abdominal ultrasonography, laparotomy, and nested polymerase chain reaction (PCR) and in situ hybridization (ISH) assays. The serum, nasal swab, oral swab, and liver biopsy were positive for EqPV-H according to the PCR assay. Genetic analysis of the partial NS1 gene of EqPV-H showed a unique nucleotide substitution, distinct from that in previously deposited strains. EqPV-H DNA was found not only in hepatocytes but also in bile duct epithelium and Kupffer cells, particularly via ISH. To the best of our knowledge, this is the first case of EqPV-H-associated TD in Asia, providing the first clinical evidence for viral shedding from the mouth and nose, and identification of EqPV-H in the liver. This study contributes to a better understanding of the pathological features of EqPV-H-associated TD.

Evaluation of the protective effects of a nanogel-based vaccine against rabbit hepatitis E virus.

Infection with hepatitis E virus (HEV) has raised serious public health concerns worldwide. In this study, a nanogel-based vaccine encapsulating the capsid protein of rabbit HEV was developed and its protective efficacy was compared with a subunit vaccine. A total of 23 rabbits were divided into 5 groups: (1) negative control (n = 4), (2) positive control (n = 4), (3) nanogel control (n = 5), (4) nanogel vaccine (n = 5), and (5) subunit vaccine (n = 5). Rabbits were vaccinated two times, at weeks 0 and 1, with nanogel and subunit vaccines, respectively, and challenged with rabbit HEV at week 4. By week 11, rabbits vaccinated with the nanogel vaccine produced higher antibodies than those vaccinated with the subunit vaccine. Fecal viral shedding and viremia were identified in rabbits of the positive and nanogel control groups at weeks 6-10. However, there was no viral shedding and viremia in rabbits immunized with both the nanogel and subunit vaccines. Alanine aminotransferase and aspartate aminotransferase levels were not elevated in any rabbit. However, histopathological examination revealed much less hepatic inflammation in rabbits of the nanogel vaccine group compared to the positive and nanogel control groups. Significant increases in IL-12 and IFN-γlevels were identified from rabbits immunized with the nanogel vaccine. Collectively, these results indicate that the newly developed nanogel vaccine induced sufficient immunity leading to complete protection from HEV infection in rabbits. Application of this vaccine should be considered as a preventive measure against HEV infection in other animal species and humans.

Comparison of the Oral Microbiomes of Canines and Their Owners Using Next-Generation Sequencing.

The oral microbiome, which is closely associated with many diseases, and the resident pathogenic oral bacteria, which can be transferred by close physical contact, are important public health considerations. Although the dog is the most common companion animal, the composition of the canine oral microbiome, which may include human pathogenic bacteria, and its relationship with that of their owners are unclear. In this study, 16S rDNA pyrosequencing was used to compare the oral microbiomes of 10 dogs and their owners and to identify zoonotic pathogens. Pyrosequencing revealed 246 operational taxonomic units in the 10 samples, representing 57 genera from eight bacterial phyla. Firmicutes (57.6%), Proteobacteria (21.6%), Bacteroidetes (9.8%), Actinobacteria (7.1%), and Fusobacteria (3.9%) were the predominant phyla in the human oral samples, whereas Proteobacteria (25.7%), Actinobacteria (21%), Bacteroidetes (19.7%), Firmicutes (19.3%), and Fusobacteria (12.3%) were predominant in the canine oral samples. The predominant genera in the human samples were Streptococcus (43.9%), Neisseria (10.3%), Haemophilus (9.6%), Prevotella (8.4%), and Veillonella (8.1%), whereas the predominant genera in the canine samples were Actinomyces (17.2%), Unknown (16.8), Porphyromonas (14.8), Fusobacterium (11.8), and Neisseria (7.2%). The oral microbiomes of dogs and their owners were appreciably different, and similarity in the microbiomes of canines and their owners was not correlated with residing in the same household. Oral-to-oral transfer of Neisseria shayeganii, Porphyromonas canigingivalis, Tannerella forsythia, and Streptococcus minor from dogs to humans was suspected. The finding of potentially zoonotic and periodontopathic bacteria in the canine oral microbiome may be a public health concern.

Development of porcine respiratory and reproductive syndrome virus replicon vector for foot-and-mouth disease vaccine.

PURPOSE: Foot-and-mouth disease (FMD) is an economically important global animal disease. To control FMD virus (FMDV) outbreaks, a lot of different novel approaches have been attempted. In this study, we proposed a novel porcine reproductive and respiratory syndrome virus (PRRSV) as a replicon vector to express FMDV structural protein. MATERIALS AND METHODS: PRRSV infectious clone (PRRSVK418DM) was used to develop an expression vector through the reverse genetic manipulation of PRRSV; FMDVP12A3C gene of serotype O was synthesized and used for an antigen. MARC-145 cells (African green monkey kidney epithelial cell line) were used for electroporation mediated transfection. The transfection or the expression of P12A3C and N protein of PRRSV was analyzed by either replicon containing PRRSV alone or by co-infection of helper PRRSV. RESULTS: We constructed PRRSVK418DM replicon vector containing FMDVP12A3C, and genome sequences were confirmed by subsequent sequence analysis. In vitro expression of P12A3C and PRRSV N protein was confirmed by immunofluorescence antibody assay using antibodies specific for PRRSV N protein (anti-PRRSV N MAb), FMDV-VP1 (anti-VP1 MAb). CONCLUSION: The results indicate that PRRSV replicon vector can be a promising novel vector system to control FMDV and useful for vaccine development in the future.