Background: Enterobacter hormaechei is commonly considered a causative pathogen for nosocomial infections and it does not usually cause diseases in animals. However, researchers have recently dissociated the pathogenic Enterobacter hormaechei from foxes and piglets. Here, the Enterobacter hormaechei was first found to be associated with respiratory disease in unweaned calves in China. Case presentation: A 2-month-old calf was severely sick and diagnosed with respiratory infection by a rural veterinarian, and it died 5 days after treatment with penicillin G. The lung sample was then run through histopathological analysis and pathogen isolation. The sequence analysis and biochemical tests results showed the isolated bacterium strain to be Enterobacter hormaechei, and drug sensitivity tests showed resistance to all β-lactam antimicrobials and sensitivity to quinolones. Thickened alveoli septum, inflammatory cell infiltration, and erythrocyte diapedesis around the pulmonary alveoli septum were visible in lung histopathological sections. One week later, at the same farm, another calf showed similar clinical signs, and the Enterobacter hormaechei strain was isolated from its nasal discharge; after a week of treatment with enrofloxacin, as suggested by the results of drug sensitivity tests, this calf fully recovered. Conclusions: To the best of our knowledge, this is the first case report of calves with respiratory disease that was associated with E. hormaechei, and multi-drug resistance was observed in isolates.

Classical swine fever (CSF) is one of the most devastating and highly contagious viral diseases in the world. Since late 2014, outbreaks of a new sub-genotype 2.1d CSF virus (CSFV) had caused substantial economic losses in numbers of C-strain vaccinated swine farms in China. The objective of the present study was to explore the genomic characteristics and pathogenicity of the newly emerged CSFV isolates in China during 2014–2015. All the new 8 CSFV isolates belonged to genetic sub-genotype 2.1d. Some genomic variations or deletions were found in the UTRs and E2 of these new isolates. In addition, the pathogenicity of HLJ1 was less than Shimen, suggesting the HLJ1 of sub-genotype 2.1d may be a moderated pathogenic isolate and the C-strain vaccine can supply complete protection. The new CSFV isolates with unique genomic characteristics and moderate pathogenicity can be epidemic in many large-scale C-strain vaccinated swine farms. This study provides the information should be merited special attention on establishing prevention and control policies for CSF.

Porcine circovirus type 3 (PCV3) is a newly emerging circovirus that might be associated with porcine dermatitis and nephropathy syndrome, reproductive failure, and cardiac and multisystemic inflammation. To aid the prevention and control of the infectious disease caused by PCV3, we developed a novel isothermal amplification assay using polymerase spiral reaction (PSR), which allows the visual detection of preserved strains and clinical samples. This assay precisely amplified the PCV3 genome with the use of a water bath at 62 °C for 50 min. The detection limit was found to be 1.13 × 102 copies/μL by gel electrophoresis or with the use of a visible dye (an indicator comprising phenol red and cresol red). No cross-reaction with other porcine infectious viruses was observed. The detection results for 23 PCV3-positive samples by PSR were in accordance with loop-mediated isothermal amplification (LAMP) assay. The detection rate of the PSR assay for PCV3 positivity of clinical samples was 68/97, which was higher than LAMP assay (67/97). These results indicated that the PSR assay provides an accurate and rapid method for the detection of PCV3 with high sensitivity and specificity. It is particularly suited for use in a simple laboratory setting without a thermal cycler or gel electrophoresis equipment.

Avian gyrovirus 2 (AGV2), which is similar to chicken infectious anemia virus, is a new member of the genus Gyrovirus. AGV2 has been detected not only in chicken but also in human tissues and feces. This study analyzed 91 samples (8 from liver tissue and 83 from fecal samples) collected from king ratsnakes (Elaphe carinata) from 7 separate farms in Hubei and Henan, China, for AGV2 DNA using PCR. The results demonstrated a low positive rate of AGV2 (6.59%, 6/91) in the snakes, and all the positive samples were collected from the same farm. The AGV2 strain HB2018S1 was sequenced, and its 2376 nt genome comprised three partially overlapping open reading frames: VP1, VP2, and VP3. Phylogenetic analysis revealed that the HB2018S1 and NX1506-1 strains from chickens in China belong to the same clade and that they have a nucleotide identity as high as 99.5%. Additionally, recombination analysis showed that HB2018S1 might originate from the recombination of viruses similar to those detected in chickens and a ferret. A total of 10 amino acid mutation sites (44(R/K), 74(T/A), 256 (C/R), 279(L/Q), and 373(V/A) in AGV2 VP1; 60(I/T), 125(T/I), 213(D/N), and 215(L/S) in AGV2 VP2; and 83(H/Y) in AGV2 VP3) different from those observed in most reference strains were found in the genome of HB2018S1, indicating that the differences may be related to a transboundary movement among hosts, which needs further elucidation. To the best of our knowledge, this study is the first report on an AGV2-infected poikilotherm, suggesting that cross-host transmission of viruses with circular single-stranded DNA genomes would be a public health concern.