<div>Background: Infectious coryza is an acute, highly contagious respiratory disease of chickens caused by Avibacterium paragallinarum causing heavy economical loss to the poultry farmers. The laboratory diagnosis of Av. paragallinarum infection is based mainly on conventional methods such as isolation and identification of the organisms. In modern poultry industry, the rapid diagnosis of Av. paragallinarum is essential along with detection of variation among the serotypes.&nbsp;&nbsp; 
 
Methods: A total of 128 samples (viz., heart blood swabs, tracheal, eye and infra orbital swabs) suspected for infectious coryza were screened for the presence of Av. paragallinarum by isolation and molecular characterization. Information regarding farm/flock strength, age of birds, method of rearing, production performance, clinical symptoms manifested and mortality patterns from various organized poultry farms were recorded. A total of five isolates of Av. paragallinarum have been recovered from suspected materials processed for isolation. Two isolates were sequenced and analysed.&nbsp; 
 
Result: All the isolates showed same biochemical characters but exhibited variability in the fermentation of mannose, mannitol and sorbitol. The nucleotide variation of Av. paragallinarum present in Indian subcontinent differs in their virulence and pathogenicity. The study was also focused for the molecular characterisation of Avibacterium species from different isolates. Though the clinical signs and gross pathological signs were similar, the nucleotide variation between isolates was observed. Sequencing of &lsquo;hagA&rsquo; gene showed that the two isolates were closely related to the strains of China, Australia, Mexico and India which shared 94-100% homology.</div>

Detection and Molecular Characterization of Avibacterium paragallinarum from Poultry

Background: Infectious coryza, caused by Avibacterium paragallinarum, presents economic challenges to the global poultry industry. Previous research highlighted a highly virulent Av. paragallinarum strain (ZJ-C), which demonstrated a thousandfold increased virulence compared to a standard strain (Modesto) and evaded existing vaccine protection. This study aimed to conduct a comprehensive genomic analysis of two distinct Av. paragallinarum serogroup C strains, focusing on the pathogenic potential and resistance profiles. 
 
Methods: High-throughput sequencing technology was employed to assemble and analyze the genomic sequences of the ZJ-C (highly virulent) and Modesto (reference) strains. Comparative genomic analysis was facilitated by sophisticated tools like Mauve and BLAST Ring Image Generator and comprehensive databases such as the Virulence Factor Database and Comprehensive Antibiotic Resistance Database. Additionally, the virulence differences predicted by genomic analysis were experimentally validated using a chicken infection model. 
 
Result: The study identified variations in gene composition, including virulence genes, antibiotic resistance genes and metabolic pathways. Comparative analysis showed that the ZJ-C strain demonstrates increased resistance to antibiotics and higher infectivity compared to the Modesto strain. Unique virulence genes and resistance pathways in ZJ-C suggest evolutionary adaptability. Significant disparities in protein ortholog gene clusters and metabolic pathways were uncovered, indicating strain-specific adaptations. Animal infection experiments confirmed that the ZJ-C strain induced significantly more severe and prolonged clinical symptoms compared to Modesto, validating genomic predictions regarding virulence differences. Our findings offers valuable insights of the genomic landscape and pathogenicity of Av. paragallinarum, important for informing future vaccine research and disease control strategies. The study highlights the importance of genomic analysis in understanding pathogenicity, resistance profiles and host interactions of Av. paragallinarum, crucial for improving disease management in the poultry industry.

Comprehensive Genomic Analysis of Two Avibacterium paragallinarum Strains with Significantly Different Virulence

<div>Background: Infectious coryza is a bacterial disease caused by Avibacterium paragallinarum which causes acute respiratory disease in chickens but it is also reported in Indian peafowls. Although this is a treatable condition in peafowls but need to diagnose and treat as earliest possible to save peafowls. The aim is to present reported cases of infectious coryza in peafowls.&nbsp; 
 
Methods: From 2017 to 2020 total seven cases of peafowls showing symptoms of swollen eyes, sticky discharge from eyes and nostrils, closed eye lids due to swelling, purulent discharge from eyes and caseous masses were also observed while pressing of swelling over eyes were reported from different part of Solapur district. Gasping was common symptom observed in all the peafowls. All the cases were confirmed as infectious coryza on the basis of symptoms, though the ocular and nasal swabs were submitted for bacterial isolation to the laboratory. All peafowls were treated by using parenteral antibiotic injection Gentamicin @ 4.4 mg/kg of body weight and non-steroidal anti inflammatory drugs (NSAID) injection Meloxicam @ 0.2 mg/kg of body weight and cleaning of eyes with distilled water and instillation of gentamicin and diclofenac eye drops, oral administration of multivitamins and energy drinks. 
 
Result: Out of seven cases, 6 were female and 1 was male peafowl. Recovery rate was 85.71% and all recovered peafowl were released back in the nature. Recovery was depending on severity of symptoms and all six birds recovered within one to three weeks&rsquo; time.</div>

Detection and Molecular Characterization of Avibacterium paragallinarum from Poultry

Comprehensive Genomic Analysis of Two Avibacterium paragallinarum Strains with Significantly Different Virulence

Reports of Infectious Coryza in Peafowls (Pavo cristatus) at Solapur District of Maharashtra, India