Avian Pathology最新文献

Research highlights: Protection against E. coli (EPS) challenge seems to be genotype-serotype-specific.Genotype B (O78:H4) gave (almost) full protection against genotypes B, F and H (all O78:H4).Genotype D (O11:H12) incited partial protection.Genotypes A (O1:H7) and C (O2:H1) were not protective.

Research highlights: UhpAB increases the pathogenicity of APEC.UhpAB activates the expression of virulence genes fepG, ldrD, ycgV, and ydeI.UhpAB promotes biofilm formation and enhances stress tolerance.UhpAB contributes to APEC evading attack by the host immune system.

Research highlights: Type O8 is the most prevalent serotype of APEC isolated from Wenchang chicken embryos (Hainan, China).The isolates were more than 90% resistant to erythromycin, amoxicillin, ampicillin, and tetracycline.19.2% of the isolates were multi-resistant to more than 14 antibiotics.APEC of the same serotype isolated from Hainan Wenchang embryos have close relationships in the evolutionary tree of the core genome.

In the last decade, the emergence of variant strains of avian orthoreovirus (ARV) has caused an enormous economic impact on the poultry industry across China and other countries. This study aimed to evaluate the molecular evolution of the ARV lineages detected in Chinese commercial broiler farms. Firstly, ARV isolation and identification of commercial broiler arthritis cases from different provinces in China from 2016 to 2021 were conducted. A total of 51 pure ARV isolates were obtained. Sequencing results showed that there were five genotypes of the strains isolated in this study, of which genotype 1 ARV predominated, accounting for 56.9% (29/51). The whole gene sequences of 19 ARV representative isolates were successfully obtained. The genetic evolution analysis of 10 genome segments of 19 ARV isolates showed that the σC-encoding gene had evolved into six different lineages, while the other genome segments only differentiated into two to four different lineages. The results of recombination analysis showed that recombination events were present in the L3, M1 and S1 genome segments. Analysis of the variation of the key factor σC protein showed that the nucleotide and amino acid homologies of the σC were low among the different genotypes. Three-dimensional structural visualization analysis showed that all the structural changes of σC protein were concentrated in the spherical domain at the C-terminal, which is associated with host receptor binding.

Research highlights: Hierarchical molecular testing is recommended for the detection of avian C. psittaci.Key molecular tests for surveillance were conventional PCR and quantitative PCR.The most used genomic target to detect C. psittaci in birds was the ompA gene.

Research highlights: Wild birds sampled in Italy tested for aMPV detection and characterization.aMPV-B found for the first time in a wintering Northern shoveler.Close phylogenetic relationship with aMPV-B strains circulating in Italian poultry.

Research highlights: The cost of coccidiosis in chickens fluctuates considerably, peaking in 2022.Three new Eimeria species can infect chickens and escape current vaccines.Eimeria infection exerts wide-ranging effects on enteric microbiota.

The haemolysin co-regulatory protein (Hcp) plays a significant role in the pathogenicity of avian pathogenic Escherichia coli (APEC) as an effector protein of the type VI secretion system (T6SS) to the host. Meanwhile, mitochondria in the host are the target of effector proteins of various secretion systems. Here, we explored the effects of APEC effector Hcp2b on the mitochondria of DF-1 cells and found that Hcp2b results in damage in mitochondria. Next, 68 target proteins in DF-1 cell lysates were identified that interacted with Hcp2b by streptavidin-biotin pull-down assay combined with LC-MS/MS, among which ADP/ATP transporter carrier (SLC25A4) is a mitochondria-associated protein; protein docking analysis showed that Hcp2b binds well to SLC25A4. Therefore, we hypothesize that the Hcp2b contributes to mitochondrial damage in DF-1 cells through interaction with the SLC25A4.

Reticuloendotheliosis virus (REV) is a species of the genus Gammaretrovirus that can cause neoplasia, immunosuppression, and runting-stunting syndrome. To show the clinical relevance of REV is complicated, and requires the demonstration of the virus, REV antibodies, the presence of typical gross and microscopic lesions, and the exclusion of other oncogenic agents in the case of the presence of tumours. Under field conditions, the first tests to be used might be a commercially available REV antibody ELISA or an RT-PCR to detect the REV genome. In this short paper, we present the experiences with two commercially available ELISAs and RT-PCR that we have gained from a REV outbreak on a large multi-age layer farm and many follow-up tests on samples from control farms with and without a known history of REV and fowlpox virus (FPV). In the field, some of the FPV field strains contain large inserts of the REV genome that might interfere with REV testing. The results of the ELISAs on sera from REV- and FPV- unsuspected flocks suggested that the cut-offs of both ELISAs were somewhat low resulting in a lower specificity. However, cut-offs of 2000 and 3050 for the IDEXX and BioChek ELISAs, respectively, gave an agreement of 100%, suggesting that these cut-offs might be advisable to use. The use of the combination of RT-PCR for REV and PCR for FPV proved to be very useful in separating REV infections from FPV infections. The results of our extended field study can help to interpret REV testing results.

Research highlights: Avian reovirus-infected hens shed virus heavily at 2-3 days post-inoculation.Shedding became minimal after 5-7 days post-inoculation.ARV variants offered 100% protection in hens upon subsequent infections.Infected hens maintained normal egg production with no observable clinical signs.