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Background H9N2 avian influenza viruses (AIV) has a worldwide geographic distribution and affects poultry of different types of production. H9N2 AIV was first reported in the Northeast of Algeria in April 2017, following an outbreak associated with high mortality, in broiler flocks. In the present study, we report full-length genome sequences of AIV H9N2, and the detailed phylogeny and molecular genetic analyses. Methods Ten AIV H9N2 strains, collected in broiler flocks, were amplified in 9-day-old embryonated specific pathogen free (SPF) chicken eggs. Their full-length genomes were successfully sequenced and phylogenetic and molecular characterizations were conducted. Results Phylogenetic analysis showed that the isolates were monophyletic, grouped within the G-1 lineage and were very close to Moroccan and Algerian strains identified in 2016 and 2017, respectively. The low pathogenicity of the strains was confirmed by the sequence motif (335RSSR/GLF341) at the hemagglutinin (HA) cleavage site. An exclusive substitution (T197A) that had not been previously reported for H9N2 viruses; but, conserved in some pandemic H1N1 viruses, was observed. When compared to the G1-like H9N2 prototype, the studied strains showed one less glycosylation site in HA, but 2–3 additional ones in the stalk of the neuraminidase (NA). The HA protein harbored the substitution 234 L, suggesting binding preference to human-like receptors. The NA protein harbored S372A and R403W substitutions, previously detected in H9N2 from Asia and the Middle East, and especially in H2N2 and H3N2 strains that caused human pandemics. Different molecular markers associated with virulence and mammalian infections have been detected in the viral internal proteins. The matrix M2 protein possessed the S31N substitution associated with drug resistance. The non-structural 1 (NS1) protein showed the “GSEV” PDZ ligand (PL) C-terminal motif and no 80–84 deletion. Conclusion Characterized Algerian AIV isolates showed mutations that suggest increased zoonotic potential. Additional studies in animal models are required to investigate the pathogenicity of these H9N2 AIV strains. Monitoring their evolution in both migratory and domestic birds is crucial to prevent transmission to humans. Implementation of adequate biosecurity measures that limit the introduction and the propagation of AIV H9N2 in Algerian poultry farm is crucial.

The present work was conducted to evaluate the effect of prophylactic treatments using an ionophore anticoccidial (lasalocid sodium, 100 ppm) and a prebiotic (beta-glucans and oligosaccharides, 0.5 ppm) on coccidiosis and immune reactions against it in experimentally infected broiler chickens. A total of 120 chicks were equally divided into four groups. The first group (A) served as control and received the basal diet with no additives, while the other groups (B, C and D) served as tests and their birds were given the basal diet supplemented respectively with an anticoccidial (Avatec ® ), a prebiotic (Alphamune ® ) or a combination of them. Coccidiosis was induced in broiler chickens using a mixture of E. acervulina and E. maxima at the 14th day of age. By the end of the experimentation, better health condition and production performances were recorded in birds of the last group (D), in which a decrease in coccidia replication and lesional scores were found in association with low oocysts shedding kinetics and a stimulated immune system (increased lymphoid organs weights, indices and a bigger number of lymphocytes). Our findings confirm the effectiveness of the prebiotic-anticoccidial combination in the control of coccidia infections in broiler chickens.

Infectious Bronchitis (IB) of chicken is a viral disease caused by a Coronavirus (IBV). It is worldwide distributed and characterized by its heavy economic impact on the poultry industry. The objective of this study is to elucidate the molecular aspect of the IBV, to describe the humoral and cellular immune responses, especially those played by cytotoxic T lymphocytes in the control of this infection in addition to the role played by each of the viral proteins S and N in the induction of those immune reactions. Biotechnological advances (especially gene therapy) in the IB control have been assessed by several researchers; however they are still facing some constraints. Development of new vaccines against IBV involves detailed knowledge of its antigenic structure and of the specific Cytotoxic T Lymphocytes (CTL) epitopes.

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