Avian Pathology最新文献

The poultry population is an integral part of Ethiopia's Gross Domestic Product (GDP) but, due to various infectious diseases such as infectious bursal disease (IBD), the expected economic impact in the country remains limited. The status of the disease in Ethiopia is obscured; thus, a systematic review and meta-analysis were employed to estimate the overall pooled prevalence of IBD in Ethiopia. Meta-analysis was conducted to determine the effects of each identified risk factor, while meta-regression and sub-group analysis were employed to assess the relationship between study-level covariates and effect size. The pooled prevalence of IBD in Ethiopia was 69.4% (95% CI 30.7-96.2), while the pooled logit prevalence was 0.94 (95% CI: 0.68-1.20) with significant inter-study variance (Q test = 948.28, df = 43, P < 0.001; τ² = 0.71, I²= 95.47%). A small-study effect was detected in the regression-based Egger test (Prob > |z| < 0.0001). Significant variation was observed among different groups such as sex, age, breed, and type of farm of the chickens. The effect size for the study period from 2018 to 2021 was significantly lower by -0.204 compared to the study period from 2009 to 2015 (P < 0.0001. In conclusion, the IBD pooled prevalence estimate is high, even though the number of studies in the country is insufficient. The high prevalence of the disease requires prompt attention from all stakeholders in the sector to bring it under control through comprehensive disease prevention and control intervention strategies.

Research highlights: Typical E. cecorum lesions can be reproduced in SPF broilers after intravenous, aerosol and oral inoculations.The respiratory route is potentially an infection route for pathogenic E. cecorum bacteria.Co-infections tested in this study or dexamethasone do not exacerbate the proportion of E. cecorum lesions.M.s. in combination with IBV or NDV vaccines exacerbates the proportion of positive reisolations.Immunosuppression induced by early CAV infection increases the proportion of positive reisolations.

Salmonella Pullorum (S. Pullorum) and Salmonella Gallinarum (S. Gallinarum) are the biovars of Salmonella enterica serovar Gallinarum that are responsible for pullorum disease and fowl typhoid, respectively, in poultry. Traditional serological methods fail to quickly differentiate between these biovars due to their identical O antigenic factors (O9 and O12). Although single nucleotide polymorphism (SNP)-based methods have been used to distinguish between the biovars, they often lack the required accuracy and effectiveness. In this study, we developed a PCR high resolution melt (PCR-HRM) assay, which targeted a SNP at position 665 of the fimH gene, for rapid differentiation between S. Pullorum and S. Gallinarum. Our method showed 100% specificity and was able to detect as little as 0.033 pg of S. Pullorum DNA and 0.027 pg of S. Gallinarum DNA. The PCR-HRM results for 547 clinical isolates were in complete agreement with traditional serological methods. This PCR-HRM assay significantly reduced identification time and provided high throughput, efficient testing. This makes it a practical and reliable tool for accurate differentiation between S. Pullorum and S. Gallinarum in clinical settings.

Ascites syndrome (AS) is a deadly condition in fast-growing chickens, preceded by pulmonary arterial hypertension (PAH), where the angiotensin II type 1 receptor (ATR1) plays a role. We investigated whether allicin (ALLI), a garlic derivative, could (a) interact with broiler ATR1, (b) affect ascites-related traits [haematocrit content (Hct%), blood oxygen saturation (SaO₂), and the right-to-total ventricular weight ratio (RV:TV)], (c) modify ATR1 expression in the lung, heart, and liver, alongside ascites mortality and growth performance in Ross 308 broilers raised at high altitude and under cold temperatures promoting PAH/AS. Three groups (n = 70 each) were studied: 0-ALLI (untreated), 1-ALLI (allicin 1 mg/kg bodyweight/daily at 14-27 days of age by oral-oesophageal route), and 2.5-ALLI. After 3-6 weeks, Hct%, SaO₂, RV:TV ratios, and ATR1 expression in the lung, heart, and liver, were evaluated. Weekly productive performance and AS mortality were recorded. Molecular dockings and dynamic simulations predicted that ALLI might inhibit broiler ATR1 in a transitory manner. At 42 days of age, birds in the 2.5-ALLI group exhibited lower Hct% and lower RV:TV values, while ALLI marginally enhanced SaO₂. ATR1 expression in the 1-ALLI and 2.5-ALLI groups was higher (i.e. restored) in the lungs and heart, respectively, but not in the liver compared with the untreated group. Productive performance remained unaffected by ALLI, and 2.5-ALLI provided a protection of 4.3% against ascites mortality. In conclusion, 2.5-ALLI mitigated PAH/AS traits in the lungs and heart without compromising broiler productive performance. Further studies adjusting ALLI doses and combinations are warranted. RESEARCH HIGHLIGHTSBroilers bred at >2000 m OSL and <20°C were treated with 1 or 2.5 mg allicin per os.Allicin at 2.5 mg per os decreased haematocrit and right ventricular hypertrophy.Allicin treatments restored ATR1 expression in the heart and lungs.Productive performance of broilers was not affected by allicin treatments.Allicin is a promising candidate to enhance the quality of poultry production.

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.