Rothia nasimurium was known previously as an opportunistic pathogen of animals. However, there are few reports regarding the pathogenicity of Rothia nasimurium. In September 2020, geese contracted a disease of unknown cause which brought economic losses to a farm in Jiangsu Province, China, prompting a series of investigations. The bacterium was isolated, cultured, and purified, and then identified using Gram staining, biochemical tests, matrix-assisted laser desorption/ionization time of flight mass spectrometry, and 16S rRNA sequence analysis. After determining the obtained bacteria species, antibiotic susceptibility tests and animal regression experiments were carried out. A strain of bacterium was successfully isolated from the livers of the diseased geese, which was identified as a strain of the Gram-positive bacterium Rothia nasimurium according to the 16S rRNA sequencing results. By indexing references, no goose was reported to have been infected with Rothia nasimurium. The antibiotic susceptibility testing showed that only four antibiotics (amikacin, cefazolin, fosfomycin, and ampicillin/sulbactam) could effectively inhibit the growth of the Rothia nasimurium strain. The animal regression experiments showed that the novel isolated strain could infect goslings, and it also causes serious depilation of goslings. The results of the manuscript expanded the range of pathogenic microorganisms in geese, which is helpful to develop methods for avian endemic control.

Background: Goose parvovirus (GPV) has spread globally and causes huge ecomonic loss to poultry industry. Although the attenuated GPV vaccines play vital roles in preventing the disease caused by GPV, the molecular basis for the attenuation of GPV is barely known. Results: A highly attenuated GPV strain GPV-CZM-142 was generated through blindly passaging of the highly pathogenic strain GPV-CZM in goose embryo fibroblasts (GEF) for 142 generations. The virulence of the GEF-adapted GPV strain was 10000 times less than that of the wild type GPV-CZM based on the ELD50. Genome sequencing revealed that a novel insertion in ITR and host adapted mutations in NS and VP1 were found in GPV-CZM-142 in comparison with the wild type strain.Conclusions: The generation of the highly attenuated GPV strain GPV-CZM-142 and the identified virulence-related insertion/mutation profile in the genome not only provided GPV attenuated vaccine candidate, but also gives novel insights into the molecular determinants for GPV attenuation.

Background: Porcine epidemic diarrhea (PED) is an acute and highly contagious infectious disease caused by the porcine epidemic diarrhea virus (PEDV) that occurs most frequently from winter to spring. It is associated with high morbidity and mortality rates, especially among piglets, and causes huge losses in the pig industry. The aim of this molecular epidemiological study was to identify the current strains of PEDV that are prevalent in Jiangsu Province, China.Methods: From winter 2020 to spring 2021, 793 small intestine tissue, fecal, and anal swab samples were collected from 72 pig farms in 11 counties in the jurisdiction of 5 regions of Jiangsu Province (Yancheng, Suqian, Changzhou, Xuzhou, and Yangzhou). A highly variable region of the S gene was amplified and sequenced, and phylogenetic analysis was conducted to compare this sequence with corresponding sequences from reference strains deposited in GenBank. Results: A total of 457 samples from 57 pig farms were positive for PEDV: this implies a positivity rate of 79% (57/72) for pig farms and a sample positivity rate of 57.6% (457/793). The positivity rates were 78% (107/137) in Yancheng, 53% (218/409) in Suqian, 48% (94/195) in Changzhou, 80% (16/20) in Xuzhou, and 88% (14/16) in Yangzhou. Seven representative samples were selected for sequencing, and phylogenetic analysis showed that the seven isolated strains exhibited 88.0%–100% nucleotide identity and 87.3%–99% amino acid identity. Additionally, our isolates exhibited 88.3%–99.7% nucleotide identity and 88%–98.5% amino acid identity with the reference PEDV strains. Phylogenetic tree analysis indicated that there were considerable difference in the sources of the variants.Conclusions: PEDV had a high infection rate among pigs and is possibly the main pathogenic agent of pig diarrhea in Jiangsu province. Importantly, vaccines must be screened for their efficacy against the newly identified variants.

Background: Goose parvoviruses (GPVs) spread globally and cause a huge economic loss to the poultry industry. Although the attenuated GPV vaccines play a key role in preventing the disease caused by GPV, the molecular basis for the attenuation of GPV is barely known. Results: A highly attenuated GPV strain, GPV-CZM-142, was generated through blindly passaging of the highly pathogenic strain, GPV-CZM, in goose embryonic fibroblasts (GEF) for 142 generations. The GEF-adapted GPV strain's virulence was 10,000 times weaker than its wild type counterpart, GPV-CZM, based on the ELD50 (50% Embryo Lethal Dose). By comparing with the wild type strain, genome sequencing analysis identified adapted mutations either in ITR or in NS and VP1 of GPV-CZM-142.Conclusions: The highly attenuated GPV strain, GPV-CZM-142, provides a GPV vaccine candidate, and the identified virulence-related mutations give a novel insight into the molecular determinants of GPV virulence.

Background: Goose parvoviruses (GPVs) spread globally and cause a huge economic loss to poultry industry. Although the attenuated GPV vaccines play a key role in preventing the disease caused by GPV, the molecular basis for the attenuation of GPV is barely known. Results: A highly attenuated GPV strain, GPV-CZM-142, was generated through blindly passaging of the highly pathogenic strain, GPV-CZM, in goose embryonic fibroblasts (GEF) for 142 generations. The virulence of the GEF-adapted GPV strain was 10000 times weaker than that of its wild type counterpart, GPV-CZM, based on the ELD50. By comparing with the wild type strain, genome sequencing analysis identified a novel insertion in ITR and several other mutations in both NS and VP1 of GPV-CZM-142.Conclusions: The highly attenuated GPV strain, GPV-CZM-142, provides a GPV vaccine candidate, and the identified virulence-related insertion/mutations give a novel insight into the molecular determinants of GPV virulence.