Vaccination of Poultry Against Influenza.

The complexity of influenza A virus (IAV) infections in avian hosts leads to equally complex scenarios for the vaccination of poultry. Vaccination against avian influenza strains can be used to prevent infections from sources with a single strain of IAV. It has been used as a part of outbreak control strategies as well as a way to maintain production for both low and high pathogenicity outbreaks. Unlike other viral pathogens of birds, avian influenza vaccination when used against highly pathogenic avian influenza virus, is tied to international trade and thus is not freely available for use without specific permission.

Vacunación de aves comerciales contra la influenza aviar. La complejidad de las infecciones por el virus de la influenza A en las aves hospedadoras conduce a escenarios igualmente complejos para la vacunación en la avicultura. La vacunación contra cepas de influenza aviar se puede utilizar para prevenir infecciones provenientes de fuentes con una sola cepa del virus de influenza. Se ha utilizado como parte de las estrategias de control de brotes, así como como una forma de mantener la producción tanto en brotes de baja como de alta patogenicidad. A diferencia de otros patógenos virales de las aves, la vacunación contra la influenza aviar, cuando se usa contra el virus de la influenza aviar altamente patógeno, está vinculada al comercio internacional y por lo tanto, no está disponible para su uso sin un permiso específico.

Prolonged repeated inseminations trigger a local immune response and accelerate aging of the uterovaginal junction in turkey hens.

Artificial insemination is a standard practice in the turkey breeder industry to ensure the production of fertile eggs. Even though hens are inseminated on a weekly basis, their fertility tends to decline after a few weeks of production. Avian species have a specialized structures called sperm storage tubules (SSTs), located in the uterovaginal junction (UVJ) of the oviduct. The ability of SSTs to store sperm is directly correlated with the fertility of the hen. The objective of the study was to examine changes in the transcriptome of the turkey hen's UVJ in response to the presence of sperm at three key stages of production. We hypothesized that repeated and prolonged exposure to sperm would alter the transcriptome of the UVJ. Samples were collected from virgin hens prior to the onset of lay, as well as from sham-inseminated (extender only) and semen-inseminated hens at early lay, peak lay, and late lay. Gene expression profiling of the UVJ was examined, and a differential expression analysis was conducted through pairwise comparisons between semen- and sham-inseminated groups at each production stage and across production stages. In the early laying stage, no significant gene expression changes were found between semen- and sham-inseminated groups. However, at peak lay, genes related to lipid biosynthesis, Wnt signaling, cell proliferation, and O-glycan biosynthesis were upregulated in the semen group, while the immune response and cytokine-cytokine receptor interaction were downregulated. In the late lay stage, the transcription pathway was upregulated in the semen group, whereas the translation pathway was downregulated. The local immune response that was suppressed during peak lay was increased at the late laying stage. In the semen-inseminated group, the UVJ exhibited advanced aging at the late laying stage, evidenced by reduced telomere maintenance and translation processes. The results from this study provide valuable insights into the alteration of the UVJ function in response to the presence of sperm at different stages of production and throughout the production cycle. Targeting the modulation of local immune response and addressing aging processes after peak production could potentially prevent or delay the decline in fertility of turkey breeder hens.

Refining the definition of the avian pathogenic Escherichia coli (APEC) pathotype through inclusion of high-risk clonal groups.

Colibacillosis in poultry is a unique disease manifestation of Escherichia coli in the animal world, as one of the primary routes of entry is via the respiratory tract of birds. Because of this, a novel extraintestinal pathogenic E. coli (ExPEC) subpathotype coined avian pathogenic E. coli (or APEC) has been described. Like other ExPEC, this pathotype has been challenging to clearly define, and in the case of APEC, its role as an opportunistic pathogen has further complicated these challenges. Using 3,479 temporally matched genomes of poultry-source isolates, we show that the APEC plasmid, previously considered a defining trait of APEC, is highly prevalent in clinical isolates from diseased turkeys. However, the plasmid is also quite prevalent among cecal E. coli isolates from healthy birds, including both turkeys and broilers. In contrast, we identify distinct differences in clonal backgrounds of turkey clinical versus cecal strains, with a subset of sequence types (STs) dominating the clinical landscape (ST23, ST117, ST131, ST355, and ST428), which are rare within the cecal landscape. Because the same clinical STs have also dominated the broiler landscape, we performed lethality assays using strains from dominant STs from clinical or cecal landscapes in embryonated turkey and chicken eggs. We show that, irrespective of plasmid carriage, dominant clinical STs are significantly more virulent than dominant cecal STs. We present a revised APEC screening tool that incorporates APEC plasmid carriage plus markers for dominant clinical STs. This revised APEC pathotyping tool improves the ability to identify high-risk APEC clones within poultry production systems, and identifies STs of interest for mitigation targets.

Genomic diversity and molecular epidemiology of Pasteurella multocida.

Pasteurella multocida is a bacterial pathogen with the ability to infect a multitude of hosts including humans, companion animals, livestock, and wildlife. This study used bioinformatic approaches to explore the genomic diversity of 656 P. multocida isolates and epidemiological associations between host factors and specific genotypes. Isolates included in this study originated from a variety of hosts, including poultry, cattle, swine, rabbits, rodents, and humans, from five different continents. Multi-locus sequence typing identified 69 different sequence types. In-silico methodology for determining capsular serogroup was developed, validated, and applied to all genome sequences, whereby capsular serogroups A, B, D, and F were found. Whole genome phylogeny was constructed from 237,670 core single nucleotide variants (SNVs) and demonstrated an overall lack of host or capsular serogroup specificity, with the exception of isolates from bovine sources. Specific SNVs within the srlB gene were identified in P. multocida subsp. septica genomes, representing specific mutations that may be useful for differentiating one of the three known subspecies. Significant associations were identified between capsular serogroup and virulence factors, including capsular serogroup A and OmpH1, OmpH3, PlpE, and PfhB1; capsular serogroup B and HgbA and PtfA; and capsular serogroup F and PtfA and PlpP. Various mobile genetic elements were identified including those similar to ICEPmu1, ICEhin1056, and IncQ1 plasmids, all of which harbored multiple antimicrobial resistance-encoding genes. Additional analyses were performed on a subset of 99 isolates obtained from turkeys during fowl cholera outbreaks from a single company which revealed that multiple strains of P. multocida were circulating during the outbreak, instead of a single, highly virulent clone. This study further demonstrates the extensive genomic diversity of P. multocida, provides epidemiological context to the various genotyping schemes that have traditionally been used for differentiating isolates, and introduces additional tools for P. multocida molecular typing.