Project description:Avibacterium paragallinarum is the causative agent of infectious coryza. Here we report the draft genome sequence of reference strain 221 of A. paragallinarum serovar A. The genome is composed of 135 contigs for 2,685,568 bp with a 41% G+C content.
Project description:BACKGROUND:Avibacterium paragallinarum, the causative agent of infectious coryza, is a highly contagious respiratory acute disease of poultry, which affects commercial chickens, laying hens and broilers worldwide. METHODOLOGY:In this study, we performed the whole genome sequencing, assembly and annotation of a Peruvian isolate of A. paragallinarum. Genome was sequenced in a 454 GS FLX Titanium system. De novo assembly was performed and annotation was completed with GS De Novo Assembler 2.6 using the H. influenzae str. F3031 gene model. Manual curation of the genome was performed with Artemis. Putative function of genes was predicted with Blast2GO. Virulence factors were identified by comparison with the Virulence Factor Database. RESULTS:The genome obtained has a length of 2.47 Mb with 40.66% of GC content. Seventy five large contigs (>500 nt) were obtained, which comprised 1,204 predicted genes. All the contigs are available in Genbank [GenBank: PRJNA64665]. A total of 103 virulence factors, reported in the Virulence Factor Database, were found in A. paragallinarum. Forty four of them are present in 7 species of Haemophilus, which are related with pathogenesis, virulence and host immune system evasion. A tetracycline-resistance associated transposon (Tn10), was found in A. paragallinarum, possibly acting as a defense mechanism. DISCUSSION AND CONCLUSION:The availability of A. paragallinarum genome represents an important source of information for the development of diagnostic tests, genotyping, and novel antigens for potential vaccines against infectious coryza. Identification of virulence factors contributes to better understanding the pathogenesis, and planning efforts for prevention and control of the disease.
Project description:Avibacterium paragallinarum is the causative agent of Infectious Coryza, an acute upper respiratory tract disease in chickens. The occurrence of outbreaks has emphasized that the disease can be significant in broiler as well as layer chickens. In developing countries, infectious coryza is commonly complicated by a range of other infections, resulting in severe disease and significant economic losses. There are vaccines on the market but with limited efficiency, due to the serological differences amongst the different serogroups of A. paragallinarum. Recent advances in genomics have led to whole genome sequencing of the chicken, creating an opportunity for the use of high-throughput technology such as microarrays. The objectives of this study was to screen for gene expression patterns across clinical scores associated with the immune response in chickens infected with A. paragallinarum serovar C3, as well as to establish which biological pathways are stumulated when infected with A. paragallinarum.
Project description:The hmtp210 gene of Avibacterium paragallinarum, the causative agent of infectious coryza, encodes an outer-membrane hemagglutinin (HA) that plays an essential role in pathogenicity. A hypervariable region within this HA, which is highly antigenic, is proposed as a candidate for recombinant vaccine production. Nonetheless, little is known about its genetic variability. We performed sequencing analysis of the hmtp210 hypervariable region in 16 clinical isolates from Costa Rica and compared them with 4 vaccine strains and the hmtp210 sequences available in public databases. Except for isolate ApCR12, all isolates showed high identity with reference vaccine strains 0083 and H18. Better genetic characterization of the hypervariable region of hmtp210 is necessary to develop better immunogenic strategies and improved molecular typing methods.
Project description:The diagnosis of a concurrent infection of Avibacterium paragallinarum and fowl adenovirus (FAdV) in an infectious coryza-like outbreak in the outskirt of Beijing is reported. The primary signs of the infection were acute respiratory signs, a drop in egg production, and the presence of hydropericardium-hepatitis syndrome-like gross lesions. Laboratory examination confirmed the presence of A. paragallinarum by bacterial isolation and a species-specific PCR test. In addition, conventional serotyping identified the isolates as Page serovar A. Fowl adenovirus was isolated from chicken liver specimen and identified by hexon gene amplification. In addition, histopathologic analysis and transmission electron microscopy examination further confirmed the presence of the virus. Both hexon gene sequencing and phylogenetic analysis defined the viral isolate as FAdV-4. The pathogenic role of A. paragallinarum and FAdV was evaluated by experimental infection of specific-pathogen-free chickens. The challenge trial showed that combined A. paragallinarum and FAdV infection resulted in more severe clinical signs than that by FAdV infection alone. The concurrent infection caused 50% mortality compared with 40% mortality by FAdV infection alone and zero mortality by A. paragallinarum infection alone. To our knowledge, this is the first report of A. paragallinarum coinfection with FAdV. The case implies that concurrent infections with these 2 agents do occur and more attention should be given to the potential of multiple agents during disease diagnosis and treatment.