A perspective of the prevalent H9N2 virus with a special focus on molecular and pathological aspects in commercial broiler chicken in Punjab, Pakistan / Perspectiva do vírus H9N2 prevalente com foco especial em aspectos moleculares e patológicos em frangos de corte comerciais em Punjab, Paquistão

Frequent outbreaks of avian influenza H9N2 virus in Pakistan revealed that this subtype has become endemic in the poultry industry and, besides economic losses, poses a threat to public health. The present study describes the molecular characterization and pathological alterations in naturally infected broiler chickens with the current H9N2 field strain and their phylogenomic dynamics. In this study, tissue samples (trachea, lung, kidney and intestine) from 100 commercial chicken flocks were collected from July 2018 to August 2019. Samples were subjected to molecular detection, phylogeny and subsequent pathological examination. The complete length of the HA gene was successfully amplified in five samples. Nucleotide sequencing revealed positive samples placed in a clade belonging to the B2 sub-lineage of the G1 genotype and categorized as LPAIV based on the amino acid sequence of the HA gene at the cleavage site (PAKSSR/G). Genetic analysis of the haemagglutinin (HA) gene revealed nt: 80.5%-99.5%; aa: 83.8%-98.9% homology to H9N2 strains reported previously from Pakistan, neighbouring countries, and (A/Quail/Hong Kong/G1/97). Gross lesions include a slight airsacculitis, mild hemorrhages, diffuse congestion and purulent exudate in tracheal mucosa, fibrinonecrotic cast in the trachea lumen and mild pulmonary congestion. Histopathological alterations include sloughing of epithelial cells and infiltration of inflammatory cells in the trachea, mononuclear cells (MNCs) infiltration, pulmonary congestion and exudate in the lumen of parabronchi, peritubular congestion in the kidneys with degeneration of tubular epithelial cells and degenerative changes in the intestinal villi epithelial cells and goblet cell hyperplasia. Immunohistochemistry analysis confirmed the presence of AIVH9N2 antigen in the trachea, lungs, kidney and intestine. Electron microscopy revealed ultrastructural changes in the trachea, including degenerated cilia, mitochondrial swelling and enlarged endoplasmic reticulum. Based on all essential analysis, the present study revealed the distribution of the H9N2 virus of G1 genotype in Punjab, Pakistan, with mild to moderate pathogenicity.

Surtos frequentes do vírus da gripe aviária H9N2 no Paquistão revelaram que esse subtipo se tornou endêmico na avicultura e, além das perdas econômicas, representa uma ameaça à saúde pública. O presente estudo descreve a caracterização molecular e as alterações patológicas em frangos de corte naturalmente infectados com a atual cepa H9N2 e sua dinâmica filogenômica. Neste estudo, amostras de tecidos (traqueia, pulmões, rim e intestino) de 100 lotes comerciais de frangos foram coletadas de julho de 2018 a agosto de 2019. As amostras foram submetidas à detecção molecular, filogenia e posterior exame patológico. O comprimento completo do gene HA foi amplificado com sucesso em cinco amostras. O sequenciamento de nucleotídeos revelou amostras positivas colocadas em um clado pertencente à sublinhagem B2 do genótipo G1 e categorizado como LPAIV com base na sequência de aminoácidos do gene da hemaglutinina (HA) no local de clivagem (PAKSSR/G). A análise genética do gene da HA revelou: nt = 80,5%-99,5%; aa = 83,8%-98,9% de homologia com cepas de H9N2 relatadas anteriormente no Paquistão e em países vizinhos (A/Quail/Hong Kong/G1/97). As lesões macroscópicas incluíram aerossaculite leve, hemorragias leves, congestão difusa e exsudato purulento na mucosa traqueal, cilindro fibrinonecrótico no lúmen da traqueia e congestão pulmonar leve. As alterações histopatológicas incluíram descamação de células epiteliais, infiltração de células inflamatórias na traqueia, infiltração de células mononucleares (MNCs), congestão pulmonar e exsudato no lúmen dos parabrônquios, congestão peritubular nos rins com degeneração das células epiteliais tubulares, alterações degenerativas nas células epiteliais das vilosidades intestinais e hiperplasia de células caliciformes. A análise imunoistoquímica confirmou a presença do antígeno AIVH9N2 na traqueia, nos pulmões, no rim e no intestino. A microscopia eletrônica revelou alterações ultraestruturais na traqueia, incluindo cílios degenerados, inchaço mitocondrial e retículo endoplasmático aumentado. Com base em todas as análises, o presente estudo revelou a distribuição do vírus H9N2 do genótipo G1 em Punjab, Paquistão, com patogenicidade de leve a moderada.

A perspective of the prevalent H9N2 virus with a special focus on molecular and pathological aspects in commercial broiler chicken in Punjab, Pakistan.

Frequent outbreaks of avian influenza H9N2 virus in Pakistan revealed that this subtype has become endemic in the poultry industry and, besides economic losses, poses a threat to public health. The present study describes the molecular characterization and pathological alterations in naturally infected broiler chickens with the current H9N2 field strain and their phylogenomic dynamics. In this study, tissue samples (trachea, lung, kidney and intestine) from 100 commercial chicken flocks were collected from July 2018 to August 2019. Samples were subjected to molecular detection, phylogeny and subsequent pathological examination. The complete length of the HA gene was successfully amplified in five samples. Nucleotide sequencing revealed positive samples placed in a clade belonging to the B2 sub-lineage of the G1 genotype and categorized as LPAIV based on the amino acid sequence of the HA gene at the cleavage site (PAKSSR/G). Genetic analysis of the haemagglutinin (HA) gene revealed nt: 80.5%-99.5%; aa: 83.8%-98.9% homology to H9N2 strains reported previously from Pakistan, neighbouring countries, and (A/Quail/Hong Kong/G1/97). Gross lesions include a slight airsacculitis, mild hemorrhages, diffuse congestion and purulent exudate in tracheal mucosa, fibrinonecrotic cast in the trachea lumen and mild pulmonary congestion. Histopathological alterations include sloughing of epithelial cells and infiltration of inflammatory cells in the trachea, mononuclear cells (MNCs) infiltration, pulmonary congestion and exudate in the lumen of parabronchi, peritubular congestion in the kidneys with degeneration of tubular epithelial cells and degenerative changes in the intestinal villi epithelial cells and goblet cell hyperplasia. Immunohistochemistry analysis confirmed the presence of AIVH9N2 antigen in the trachea, lungs, kidney and intestine. Electron microscopy revealed ultrastructural changes in the trachea, including degenerated cilia, mitochondrial swelling and enlarged endoplasmic reticulum. Based on all essential analysis, the present study revealed the distribution of the H9N2 virus of G1 genotype in Punjab, Pakistan, with mild to moderate pathogenicity.

Current status of cell-based therapies for respiratory virus infections: applicability to COVID-19.

The severe respiratory consequences of the coronavirus disease 2019 (COVID-19) pandemic have prompted urgent need for novel therapies. Cell-based approaches, primarily using mesenchymal stem (stromal) cells (MSCs), have demonstrated safety and possible efficacy in patients with acute respiratory distress syndrome (ARDS), although they are not yet well studied in respiratory virus-induced ARDS. Limited pre-clinical data suggest that systemic MSC administration can significantly reduce respiratory virus (influenza strains H5N1 and H9N2)-induced lung injury; however, there are no available data in models of coronavirus respiratory infection.There is a rapidly increasing number of clinical investigations of cell-based therapy approaches for COVID-19. These utilise a range of different cell sources, doses, dosing strategies and targeted patient populations. To provide a rational strategy to maximise potential therapeutic use, it is critically important to understand the relevant pre-clinical studies and postulated mechanisms of MSC actions in respiratory virus-induced lung injuries. This review presents these, along with consideration of current clinical investigations.

Evaluation of Immune Responses and Histopathological Effects against Gamma Irradiated Avian Influenza (Sub type H9N2) Vaccine on Broiler Chicken

Abstract Vaccination is a good strategy for the prevention of avian influenza virus. In this research Gamma Irradiated Avian Influenza (Sub type H9N2) Vaccine (GAIV) was prepared by 30 kGy irradiation and used for vaccination of broiler chickens. The purpose was a comparison of immune responses in the two routes of administration for the GAIV vaccine; intranasal and subcutaneously, use of Montanide ISA70 and Trehalose accompanied with irradiated vaccine and compare with formalin vaccine. The Influenza Virus A/Chicken/IRN/Ghazvin/2001/H9N2 was irradiated and used for vaccine formulation, and formalin inactivated AIV was used as conventional vaccine. Chickens were vaccinated by GAIV with and without Trehalose, GAIV and formalin vaccines with ISA70, two routes of administration were intranasal and subcutaneously. All the vaccinated chickens showed a significant increase in antibody titration. The most significant increase of antibody titration was in irradiated vaccine plus Trehalose groups intranasal and subcutaneously. After the first and second intranasal vaccination, the amount of IFN-gamma increased in the irradiated vaccine plus Trehalose group compared to other groups. However, most of the vaccinated groups did not show any significant increase of IFN-α concentration. Histopathological examination revealed lymphocyte infiltration (++), foci dispersed of hemorrhage and edema in intranasal vaccination groups and in addition to these, thickening of alveolar septa was observed in the injection groups. GAIV vaccine can be a good candidate for vaccine preparation, and Trehalose as a stabilizer protects viral antigenic proteins, also makes more absorbance of antigen by the inhalation route. In vaccinated chickens the ulcers in injected vaccines were lower than intranasal vaccines.

MicroRNAs in avian influenza virus H9N2-infected and non-infected chicken embryo fibroblasts.

There is limited information about microRNAs (miR-NAs) in H9N2 subtype influenza virus-infected chicken cells or tissues. In this study, 10,487,469 and 13,119,795 reads were obtained from in-fected and non-infected chicken embryo fibroblasts, respectively. Seven hundred and thirty-six and 1004 miRNAs, including mature miRNAs and precursors, were obtained from the infected and non-infected fibro-blasts, respectively. Of those miRNAs, 48 were expressed differently between the groups: 37 had a low expression level in the infected chick-en embryo fibroblast, and the remaining 11 had a higher expression level. Every miRNA was predicted to target immune response-related genes. It has been found that some of the miRNAs, such as gga-miR-146c, gga-miR-181a, gga-miR-181b, gga-miR-30b, gga-miR-30c, gga-miR-30e, and gga-miR-455, are expressed differently in other types of influenza-infected chicken cells or tissues.

Effects of different NS genes of avian influenza viruses and amino acid changes on pathogenicity of recombinant A/Puerto Rico/8/34 viruses.

To examine the effects of the NS1 and NEP genes of avian influenza viruses (AIVs) on pathogenicity in mice, we generated recombinant PR8 viruses containing 3 different NS genes of AIVs. In contrast to the reverse genetics-generated PR8 (rPR8) strain and other recombinant viruses, the recombinant virus rPR8-NS(0028), which contained the NS gene of A/chicken/KBNP-0028/2000 (H9N2) (0028), was non-pathogenic to mice. The novel single mutations of 0028 NS1 to corresponding amino acid of PR8 NS1, G139D and S151T increased the pathogenicity of rPR8-NS(0028). The replacement of the PL motifs (EPEV or RSEV) of pathogenic recombinant viruses with that of 0028 (GSEV) did not reduce the pathogenicity of the viruses. However, a recombinant virus with an EPEV-grafted 0028 NS gene was more pathogenic than rPR8-NS(0028) but less than rPR8. The lower pathogenicity of rPR8-NS(0028) might be associated with the lower virus titer and IFN-ß level in the lungs of infected mice, and be attributed to G139, S151 and GSEV-PL motif of NS1 gene of 0028. In conclusion we defined new amino acid residues of NS1 related to mice pathogenicity and the presence of pathogenic NS genes among low pathogenic AIVs may encourage continuous monitoring of their mammalian pathogenicity.

Evaluation of a commercial ELISA kit (IDEXX) to differentiate AI virus-infected poultry from AI-vaccinated poultry (DIVA)

Vaccination programs for the control of avian influenza (AI) in poultry have limitations due to the problem of differentiating between vaccinated and virus-infected birds. The use of AI vaccination in poultry would have greater worldwide acceptance if reliable tests that clearly discriminated between naturally infected and vaccinated-only animals (DIVA) were available. In this study, to differentiate avian influenza virus (AIV)-infected chickens vs. chickens immunized with inactivated avian influenza virus, a commercial ELISA Kit (IDEXX) was used. Using HI as the reference method, the sensitivity of the commercial ELISA kit was 100% and its specificity was 100%. In the present study, we demonstrated that, 3 weeks after infection or vaccination, sera from both infected and vaccinated groups were tested positive and the difference in mean optical density between vaccinated and challenged birds, as detected by a commercial ELISA kit (IDEXX), was very small. Therefore, this assay cannot distinguish infected from vaccinated poultry.(AU)

Avian-derived NS gene segments alter pathogenicity of the A/Puerto Rico/8/34 virus.

While the effect of the influenza A virus non-structural protein (NS) on cytokine production during viral infection is well known, inconsistent results have been observed with some other influenza A virus backbone studied. In this study, in order to focus on the impact of the avian NS gene segments on viral virulence, the NS genes encoded by different strains of avian influenza A viruses were incorporated into an identical [A/Puerto Rico/8/1934(H1N1), PR8] virus background to generate various NS recombinant viruses. Thus, PR8NS, PR8×[A/Hong Kong/483/97(H5N1) 483NS, PR8×[A/Ck/Korea/150/03(H9N2) 150NS, and PR8×[A/EM/Korea/W149/06(H5N1) W149NS were constructed utilizing reverse genetics. Here, we show the effects of each of these recombinant viruses upon viral pathogenesis and cytokine production during viral replication in vivo. In this regard, we found that infection of mice with the PR8×150NS recombinant virus resulted in the lowest pathogenicity (6.0×10(4)MLD50), yet elicited the highest levels of TNF-α production in bronchoalveolar lavage (BAL) fluid compared to infection with the other recombinant influenza viruses. In contrast, infection with the PR8 virus showed the highest pathogenicity (1.0×10(2)MLD50) as well as relatively high cytokine levels (IL-1α, IL-1ß, IL-17, and eotaxin) in mouse BAL fluid. In addition, the PR8 and PR8×483NS viruses induced severe and extensive inflammation in infected lungs compared with that of PR8×150 NS recombinant virus-infected mice. These results clearly demonstrate that the NS genes of diverse influenza A strains can variable impact pathogenicity, histopathology, and cytokine production in mice even when expressed in an identical genetic background.

Effects of different polymerases of avian influenza viruses on the growth and pathogenicity of A/Puerto Rico/8/1934 (H1N1)-derived reassorted viruses.

We generated reassorted PR8 viruses containing six different combinations of avian influenza virus (AIV) polymerase genes from A/chicken/Korea/01310/2001 (H9N2) (01310) and A/chicken/Korea/KBNP-0028/2000 (H9N2) (0028) to examine the effects of the AIV polymerase genes PB1, PB2, and PA on replication efficiency in different host cells and pathogenicity in mice. The virus titers of the reassorted viruses possessing 01310 [rPR8-PB2(01310)] and 0028 [rPR8-PB2(0028)] PB2 genes were significantly higher than those of the others except the rPR8 virus in embryonated chicken eggs at 37°C, and those of avian polymerase reassorted viruses were significantly less than rPR8 in MDCK cells at 32 and 37°C. rPR8-PB2(01310), rPR8-PB2(0028), and rPR8-PA(0028) caused no body weight loss in BALB/c mice but rPR8-PA(01310), rPR8-PB1(01310), and rPR8-PB1(0028) caused mortality and significantly different body weight loss compared to those in the mock treatment. In contrast to rPR8-PB2(0028) and rPR8-PA(0028), rPR8-PB2(01310) was not isolated from infected mice, and rPR8-PB1(0028) was less pathogenic than rPR8-PB1(01310). We determined the amino acid residues that were specific to the less pathogenic polymerases. A comparison with those of pandemic 2009 H1N1, human fatal H5N1 and H7N9, and pathogenic AIVs to mice without adaptation revealed that they possessed the mammalian pathogenic constellation of polymerases. Thus, the novel polymerase genes and amino acid residues may be useful to understand the host-barrier overcome of AIVs in mice and to develop safer and efficacious vaccines.

Isolation and characterization of an H9N2 influenza virus isolated in Argentina.

As part of our ongoing efforts on animal influenza surveillance in Argentina, an H9N2 virus was isolated from a wild aquatic bird (Netta peposaca), A/rosy-billed pochard/Argentina/CIP051-559/2007 (H9N2) - herein referred to as 559/H9N2. Due to the important role that H9N2 viruses play in the ecology of influenza in nature, the 559/H9N2 isolate was characterized molecularly and biologically. Phylogenetic analysis of the HA gene revealed that the 559/H9N2 virus maintained an independent evolutionary pathway and shared a sister-group relationship with North American viruses, suggesting a common ancestor. The rest of the genome segments clustered with viruses from South America. Experimental inoculation of the 559/H9N2 in chickens and quail revealed efficient replication and transmission only in quail. Our results add to the notion of the unique evolutionary trend of avian influenza viruses in South America. Our study increases our understanding of H9N2 viruses in nature and emphasizes the importance of expanding animal influenza surveillance efforts to better define the ecology of influenza viruses at a global scale.