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A.Sabry, M., Khaled A. Abdel-Moein, Fatma Abdel-Kader, and E. Hamza, "Extended-spectrum β-lactamase-producing Salmonella serovars among healthy and diseased chickens and their public health implication", Journal of Global Antimicrobial Resistance, vol. 22, pp. 742-748, 2020.
Ahmed-Hassan, H., M. S. Abdul-Cader, M. A. Sabry, E. Hamza, S. Sharif, E. Nagy, and M. F. Abdul-Careem, "Double-Stranded Ribonucleic Acid-Mediated Antiviral Response Against Low Pathogenic Avian Influenza Virus Infection.", Viral immunology, vol. 31, issue 6, pp. 433-446, 2018 Jul/Aug. Abstract

Toll-like receptor (TLR)3 signaling pathway is known to induce type 1 interferons (IFNs) and proinflammatory mediators leading to antiviral response against many viral infections. Double-stranded ribonucleic acid (dsRNA) has been shown to act as a ligand for TLR3 and, as such, has been a focus as a potential antiviral agent in many host-viral infection models. Yet, its effectiveness and involved mechanisms as a mediator against low pathogenic avian influenza virus (LPAIV) have not been investigated adequately. In this study, we used avian fibroblasts to verify whether dsRNA induces antiviral response against HN LPAIV and clarify whether type 1 IFNs and proinflammatory mediators such as interleukin (IL)-1β are contributing to the dsRNA-mediated antiviral response against HN LPAIV. We found that dsRNA induces antiviral response in avian fibroblasts against HN LPAIV infection. The treatment of avian fibroblasts with dsRNA increases the expressions of TLR3, IFN-α, IFN-β, and IL-1β. We also confirmed that this antiviral response elicited against HN LPAIV infection correlates, but is not attributable to type 1 IFNs or IL-1β. Our findings imply that the TLR3 ligand, dsRNA, can elicit antiviral response in avian fibroblasts against LPAIV infection, highlighting potential value of dsRNA as an antiviral agent against LPAIV infections. However, further investigations are required to determine the potential role of other innate immune mediators or combination of the tested cytokines in the dsRNA-mediated antiviral response against HN LPAIV infection.

Ahmed-Hassan, H., M. S. Abdul-Cader, U. De Silva Senapathi, M. A. Sabry, E. Hamza, E. Nagy, S. Sharif, and M. F. Abdul-Careem, "Potential mediators of in ovo delivered double stranded (ds) RNA-induced innate response against low pathogenic avian influenza virus infection.", Virology journal, vol. 15, issue 1, pp. 43, 2018 03 12. Abstract

BACKGROUND: Toll like receptor (TLR) 3 is a critically important innate pattern recognizing receptor that senses many viral infections. Although, it has been shown that double stranded (ds) RNA can be used for the stimulation of TLR3 signaling pathway in a number of host-viral infection models, it's effectiveness as an antiviral agent against low pathogenic avian influenza virus (LPAIV) needs further investigation.

METHODS: In this study, first, we delivered TLR3 ligand, dsRNA, in ovo at embryo day (ED)18 since in ovo route is routinely used for vaccination against poultry viral and parasitic infections and infected with H4N6 LPAIV 24-h post-treatment. A subset of in ovo dsRNA treated and control groups were observed for the expressions of TLR3 and type I interferon (IFN)s, mRNA expression of interleukin (IL)-1β and macrophage recruitment coinciding with the time of H4N6 LPAIV infection (24 h post-treatment). Additionally, Day 1 chickens were given dsRNA intra-tracheally along with a control group and a subset of chickens were infected with H4N6 LPAIV 24-h post-treatment whereas the rest of the animals were observed for macrophage and type 1 IFN responses coinciding with the time of viral infection.

RESULTS: Our results demonstrate that the pre-hatch treatment of eggs with dsRNA reduces H4N6 replication in lungs. Further studies revealed that in ovo delivery of dsRNA increases TLR3 expression, type I IFN production and number of macrophages in addition to mRNA expression of IL-1β in lung 24-h post-treatment. The same level of induction of innate response was not evident in the spleen. Moreover, we discovered that dsRNA elicits antiviral response against LPAIV correlating with type I IFN activity in macrophages in vitro. Post-hatch, we found no difference in H4N6 LPAIV genome loads between dsRNA treated and control chickens although we observed higher macrophage recruitment and IFN-β response coinciding with the time of viral infection.

CONCLUSIONS: Our findings imply that the TLR3 ligand, dsRNA has antiviral activity in ovo and in vitro but not in chickens post-hatch and dsRNA-mediated innate host response is characterized by macrophage recruitment and expressions of TLR3 and type 1 IFNs.

Ahmed-Hassan, H., M. S. Abdul-Cader, M. A. Sabry, E. Hamza, and M. F. Abdul-Careem, "Toll-like receptor (TLR)4 signalling induces myeloid differentiation primary response gene (MYD) 88 independent pathway in avian species leading to type I interferon production and antiviral response.", Virus research, vol. 256, pp. 107-116, 2018 09 02. Abstract

Engagement of toll-like receptor (TLR)4 ligand, lipopolysaccharide (LPS) with TLR4 in mammals activates two downstream intracellular signaling routes; the myeloid differentiation primary response gene (MyD)88 dependent and independent pathways. However, existence of the later pathway leading to production of type I interferons (IFNs) in avian species has been debated due to conflicting observations. The objective of our study was to investigate whether LPS induces type I IFN production in chicken macrophages leading to antiviral response attributable to type I IFN. We found that LPS elicits type I IFN response dominated by IFN-β production. We also found that reduction in infectious laryngotracheitis virus (ILTV) replication by LPS-mediated antiviral response is attributable to type I IFNs in addition to nitric oxide (NO). Our findings imply that LPS elicits both MyD88 dependent and independent pathways in chicken macrophages consequently eliciting anti-ILTV response attributable to production of both type I IFNs and NO.

Anja, Z., H. Eman, J. Sigridur, R. Claudio, W. Bettina, S. Getraud, S. Vilhjalmur, T. Sigurbjorg, and M. Eliane, "Longitudinal analysis of allergen-specific IgE and IgG subclasses as potential predictors of insect bite hypersensitivity following first exposure to Culicoides in Icelandic horses.", Vet Dermatology, vol. 29, issue 1, pp. 51-e22, 2018.
Elhariri, M., D. Hamza, R. Elhelw, and E. Hamza, "Occurrence of cagA vacA s1a m1 i1 Helicobacter pylori in farm animals in Egypt and ability to survive in experimentally contaminated UHT milk.", Scientific reports, vol. 8, issue 1, pp. 14260, 2018 Sep 24. Abstract

Cases of human gastric cancer due to Helicobacter pylori have been reported worldwide and animals might act as a reservoir of infection in certain circumstances. The recent few decades showed a rapid decline in the incidence of gastric cancer, which was mainly due to the decrease in H. pylori infection. The aims of the present study were to determine the prevalence of H. pylori among livestock and investigate whether the animal isolates can be transmitted through contaminated milk causing gastric infection. Feces and milk samples were collected from apparently healthy cows, buffaloes, and sheep, and were examined by nested PCR and genotyping. The PCR positive samples were further subjected to bacterial culture followed by partial 16s sequencing of the isolates. Twenty-nine percent of the animals showed the presence of H. pylori, mainly the virulent cagAvacAs1a m1 i1 genotype, which is known to be associated with serious diseases in humans. The spiral viable culturable form (SVCF) of this strain was inoculated into UHT (ultra-high temperature) milk and remained viable for up to 10 days at 4 °C. Increasing period of storage and or temperature led to a decrease in the number of the SVCF and occurrence of the coccoid viable non-culturable form (CVNCF). The infectivity of the survived forms was determined by feeding healthy groups of laboratory mice with the contaminated UHT milk containing SVCF or CVNCF for 40 days. The gastric mucosa of the two mice groups showed similar levels of H. pylori load. This highlights that H. pylori can persist in contaminated milk by entering a non-culturable state, which can induce gastric infection.

Hamed, O. M., M. A. Sabry, N. A. Hassanain, E. Hamza, A. G. Hegazi, and M. B. Salman, "Occurrence of virulent and antibiotic-resistant Shiga toxin-producing Escherichia coli in some food products and human stool in Egypt.", Veterinary World, EISSN: 2231-0916, vol. 10, issue 10, pp. 1233-1240, 2017. vetworld-10-1233.pdf
Hamza, E., J. Mirkovitch, F. Steinbach, and E. Marti, "Regulatory T cells in early life: Comparative study of CD4+CD25 high T cells from foals and adult horses", PLOS ONE, vol. 10(3), issue e012066, 2015.
Hamza, E., M. Doherr, G. Bertoni, T. W. Jungi, and E. Marti, "Modulation of allergy incidence in Icelandic horses is associated with a change in IL-4-producing T cells", Intern Arch of Allergy and Immunology , vol. 144, pp. 325-337, 2007.
Hamza, E., S. Torsteinsdottir, M. Eydal, C. Frey, J. Mirkovitch, B. Wagner, A. D. Wislon, T. W. Jungi, and E. Marti, "Increased IL-4 and decreased regulatory cytokine production following relocation of Icelandic horses from a high to low endoparasite environment", Vet Immunol Immunopathol, vol. 133, pp. 40-50, 2010.
Hamza, E., F. Steinbach, and E. Marti, "CD4+CD25+ T cells expressing FoxP3 in Icelandic horses affected with insect bite hypersensitivity.", Vet Immunol Immunopathol, vol. 148, issue 1-2, pp. 139-144, 2012.
Hamza, E., C. A. Akdis, B. Wagner, F. Steinbach, and E. Marti, "Restoring the ability of CD4+CD25+ T cells to suppress allergen-induced proliferation of CD4+CD25- Cells in horses affected with insect bite hypersensitivity", Clinical and experimental Allergy, vol. 43, pp. 889-901, 2013.
Hamza, E., S. Kittl, and P. Kuhnert, "Temporal induction of pro-inflammatory and regulatory cytokines in human peripheral blood mononuclear cells by Campylobacter jejuni and Campylobacter coli.", PloS one, vol. 12, issue 2, pp. e0171350, 2017. Abstract

Campylobacter jejuni along with C. coli are major cause of human gastroenteritis worldwide. So far, the human immune response against Campylobacter is not entirely clear. We hypothesize that it is coordinated by an interaction between pro-inflammatory and regulatory cytokines which is influenced by bacterial and host-individual differences. Accordingly, we used peripheral blood mononuclear cells (PBMC) from healthy donors to study the primary systemic immune response to C. jejuni and C. coli. PBMC were stimulated by different strains of C. jejuni and C. coli for three time points (5, 10, 24 hours). The production of the pro-inflammatory (IL-6, IL-8, IFN-γ) and the regulatory (IL-10) cytokines were measured by ELISA. All strains induced higher levels of IL-8 and IL-6 than IFN-γ and IL-10. In contrast to IL-8 and IL-6, IL-10 showed a steeper increase over time. While IFN-γ did not show any further increase between 10 and 24 hours. Interestingly, there was a significant correlation between IL-8 and IL-10 which peaked at 24 hours. Despite the variability of the used bacterial strains, their effect on cytokine production was less pronounced than the inter-person differences. The strongest significant effect of the strain was on the level of IL-10. IL-10 and IL-6 were significantly influenced by strain-person interaction. In conclusion, the systemic immune response to C. coli and C. jejuni is characterized by an early pro-inflammatory reaction with later initiation of regulatory immune response which is influenced mainly by the host, explaining the individual variations in disease severity. Additional work is needed to determine the cellular sources of the produced cytokines as well as the campylobacter molecules that might contribute to this stimulation.

Hamza, D., S. Dorgham, E. Ismael, S. I. A. El-Moez, M. Elhariri, R. Elhelw, and E. Hamza, "Emergence of β-lactamase- and carbapenemase- producing Enterobacteriaceae at integrated fish farms ", Antimicrob Resist Infect Control . , vol. 9, issue 1, pp. 1-12, 2020.
Hamza, E., B. Wagner, T. W. Jungi, J. Mirkovitch, and E. Marti, "Reduced incidence of insect-bite hypersensitivity in Icelandic horses is associated with a down-regulation of interleukin-4 by interleukin-10 and transforming growth factor", Vet Immunol Immunopathol, vol. 122, pp. 65-75, 2008.
Hamza, E., V. Gerber, F. Steinbach, and E. Marti, "Equine CD4+CD25high T cells exhibit regulatory activity by close contact and cytokine-dependent mechanisms in vitro ", Immunology, vol. 134, pp. 292-304, 2011.
Hamza, E., S. M. Dorgham, and D. A. Hamza, "Carbapenemase-producing Klebsiella pneumoniae in broiler poultry farming in Egypt.", Journal of global antimicrobial resistance, vol. 7, pp. 8-10, 2016 Dec. Abstract

This study investigated the occurrence of carbapenem-resistant Klebsiella pneumoniae strains in broiler chickens, drinking water and humans working in contact with chickens and identified the carbapenem resistance determinants among isolates from different sources. Internal organs and droppings were collected from 100 broilers with signs of respiratory disease at five broiler farms in Egypt. Additionally, 20 drinking water samples and 49 faecal samples from workers and veterinarians working at these farms were included. Following culture on MacConkey agar, suspected K. pneumoniae colonies were identified by phenotypic testing. Susceptibility to carbapenems was tested in confirmed K. pneumoniae isolates by disk diffusion. Carbapenem-resistant isolates were subjected to PCR for detection of carbapenemase-encoding genes (blaKPC, blaOXA-48 and blaNDM). K. pneumoniae was isolated from 35% of broilers and 25% of water samples. Of the 35 poultry isolates, 15 were carbapenem-resistant; all of them were blaNDM-positive, including 11 isolates harbouring blaKPC, blaOXA-48 and blaNDM and 4 containing either blaKPC and blaNDM (n=3) or blaOXA-48 and blaNDM (n=1). Similarly, three of five K. pneumoniae isolates from drinking water were positive for blaKPC and blaNDM (n=1) or for all three genes (n=2). Interestingly, 56% of K. pneumoniae from humans displayed carbapenem resistance; all of them were positive for the three carbapenemase genes. Carbapenemase-producing K. pneumoniae occurred at relatively high frequency among broilers, drinking water and workers at poultry farms in Egypt. Additional work is needed to confirm transmission between poultry and humans and to elucidate the direction and mechanism of transmission.

Jonsdottir, S., E. Hamza, J. Janda, C. Rhyner, A. Meinked, E. L. Marti, V. Svansson, and S. Torsteinsdottir, "Developing a preventive immunization approach against insect bite hypersensitivity using recombinant allergens: A pilot study", Veterinary Immunology and Immunopathology , vol. 166, pp. 8-21, 2015.
Jonsdottir, S., E. Hamza, J. Janda, C. Rhyner, A. Meinke, E. Marti, W. Svanson, and S. Torsteinsdottir, "Developing a preventive immunization approach against insect bite hypersensitivity using recombinant allergens: a pilot study. ", Vet Immunol Immunopathol, vol. 166, issue 1-2, pp. 8-21, 2015.
Lanz, S., V. Gerber, J. Klukowska-Rötzler, H. Rettmer, E. Marti, J. Matthews, S. Pirie, and E. Hamza, "Effect of hay-dust extract and cyathostomins stimulation on cytokine expression by PBMC from horses affected with recurrent airway obstruction.", Vet Immunol Immunopathol, vol. 155, issue 4, pp. 229-237, 2013.
Mählmann, K., E. Hamza, E. Marti, J. Klukowska-Rötzler, V. Gerber, and C. Koch, "Increased FoxP3 expression in tumor associated tissues of horses affected with equine sarcoid disease", Veterinary Journal Elsevier, vol. 202, issue 3, pp. 516-21, 2014.
Marti, E., and E. Hamza, "Equine immunoglobulin E. in Veterinary Allergy, Eds Noli, C, Foster, A, Rosenkrantz W. ", Veterinary allergy, Hoboken, New Jersey, Wiley Blackwell, 2014.
Marti, E Antczak D, V. Gerber, A. D. Wilson, J. P. Lavoie, D. Horohov, R. Crameri, D. P. Lunn, D. Antczak, S. Björnsdóttir, B. TS, et al., "Report of the 3rd Havemeyer workshop on allergic diseases of the Horse, Hólar, Iceland, June 2007", Vet Immunol Immunopathol, vol. 126, issue 3-4, pp. 351-361, 2008.
Pacholewska, A., M. Drögemüller, J. Klukowska-Rötzle, S. Lanz, E. Hamza, E. T. Dermitzak, E. L. Marti, V. Gerber, T. Leeb, and V. Jagannathan, "The Transcriptome of Equine Peripheral Blood Mononuclear Cells", Plos One, vol. 10, issue 3, pp. 1-16, 2015.