RESUMEN
Infectious laryngotracheitis (ILT) is an economically crucial respiratory disease of poultry that affects the industry worldwide. Vaccination is the principal tool in the control of the disease outbreak. In an earlier study, we comprehensively characterized the circulating strains in Egypt and identified both CEO-like and recombinant strains are dominant. Herein, we investigated the pathogenicity of two virulent strains representing the CEO-like (Sharkia_2018) and recombinant strain (Qalubia_2018). Additionally, we evaluated the efficacy of different commercial vaccines (HVT-LT, CEO, and TCO) against the two isolates in terms of the histopathological lesion scores and the viral (gC) gene load. A total of 270 White Leghorn-specific pathogen-free male chicks were divided into nine groups of 30 birds, each housed in separate isolators. Birds were distributed as follows; one group was non-vaccinated, non-challenged, and served as a negative control. Two groups were non-vaccinated and infected with the two isolates of interest and served as a positive control to test the pathogenicity. Six groups were vaccinated and challenged; two groups were vaccinated with vector vaccine at one day old. The other four groups were vaccinated with either the CEO- or TCO- vaccine (two groups each) at four weeks of age. Three weeks after vaccination, birds were infected with the virulent ILTV isolates. The larynx, trachea, and harderian gland samples were taken at 1, 3, and 7 days post-infection for histopathological lesion score and molecular detection. Notably, The recombinant strain was more virulent and pathogenic than CEO-like ILTV strains. Moreover, the TCO vaccine was less immunogenic than the vector and CEO vaccines.
Asunto(s)
Infecciones por Herpesviridae , Herpesvirus Gallináceo 1 , Enfermedades de las Aves de Corral , Vacunas Virales , Animales , Pollos , Egipto/epidemiología , Infecciones por Herpesviridae/prevención & control , Infecciones por Herpesviridae/veterinaria , Herpesvirus Gallináceo 1/genética , Masculino , Eficacia de las Vacunas , Vacunas Atenuadas , VirulenciaRESUMEN
INTRODUCTION: Gallid alphaherpesvirus 2 (GaHV-2) is a highly contagious oncogenic virus that causes Marek's disease in chickens and occasionally in turkeys. Among 100 genes identified in GaHV-2 genome, the Meq gene appears to involve viral virulence, oncogenicity, and genetic diversity. Despite the use of Meq gene sequences in phylogenetic classification of GaHV-2 strains circulating in many countries worldwide, no integrated system exists yet. METHODS: Turkeys from 2 commercial Egyptian farms were presented with signs of dullness, dehydration, and emaciation. Samples prepared from the internal organs were examined by histopathology and immunohistochemistry. Pools of the internal organs were analyzed by PCR for identification of GaHV-2, avian leucosis virus, and reticuloendotheliosis virus. The Meq gene of an Egyptian strain was sequenced and analyzed in comparison to 40 reference strains for generation of a universal system for phylogenetic classification of GaHV-2 strains. RESULTS: Gross and histopathological examination revealed grayish-white soft masses in the internal organs characterized by diffuse infiltration of pleomorphic neoplastic cells. All lymphoma cells were identified as T-lymphocytes of CD3+ phenotype. Samples of both farms were only positive for GaHV-2 by PCR. Sequence analysis of the Meq gene has classified the current turkey strain as related to the Egyptian strains identified in chicken in 2012. A universal phylogenetic system for classification of GaHV-2 strains into 4 clusters was proposed. The vaccine strains were all grouped in cluster 2, and most of the classical American strains belonged to cluster 4. Cluster 1 was further divided into 3 subclusters (1.1-1.3). CONCLUSION: GaHV-2 was identified in turkeys for the first time in Africa and the Middle East. Sequence analysis of the Meq gene of the Egyptian strain along with a wide array of the global strains has enabled the construction of a novel phylogenetic classification system.
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Enfermedad de Marek , Enfermedades de las Aves de Corral , Animales , Pollos , Egipto , Filogenia , PavosRESUMEN
Infectious laryngotracheitis (ILT) is a respiratory disease that causes significant economic losses in the poultry industry worldwide. In this study, ILT outbreaks were reported on 30 farms located in eight Egyptian governorates between January 2018 and May 2019. Gross examination of diseased chickens revealed congestion and hemorrhage of laryngeal and tracheal mucosa with fibrinohemorrhagic casts and/or caseous material in the lumens. Histopathological examination showed epithelial sloughing, syncytium formation, heterophilic exudation, and development of eosinophilic intranuclear inclusion bodies. Infectious laryngotracheitis virus (ILTV) antigen was detected in the tracheal epithelium, infiltrated inflammatory cells, and syncytial cells, using immunohistochemistry. PCR targeting a portion of the thymidine kinase gene was further utilized to confirm the presence of ILTV DNA. The complete coding sequences of three envelope glycoprotein genes, gG, gD, and gJ, and a partial sequence of the infected cell polypeptide 4 (ICP4) gene from samples representing all of the farms and disease outbreaks were determined. Five prototype strains with unique sequences were chosen for detailed molecular characterization. Sequence comparisons and phylogenetic analysis of the partial ICP4 gene revealed that two strains were chicken embryo origin (CEO)-vaccine-like strains, and three were tissue culture origin (TCO)-vaccine-like strains. Analysis of the gJ gene sequence indicated that all of the strains were CEO vaccine-like strains. It was predicted that the latter three strains were recombinants of CEO- and TCO-vaccine-like strains. In conclusion, immunohistochemistry coupled with multi-genomic PCR sequencing proved to be efficient for identification and typing of ILTV strains during disease outbreaks. Both CEO-vaccine-like and recombinant virus strains were circulating in Egypt during the 2018 and 2019 outbreaks.
Asunto(s)
Pollos/virología , Infecciones por Herpesviridae/veterinaria , Herpesvirus Gallináceo 1/clasificación , Herpesvirus Gallináceo 1/genética , Proteínas del Envoltorio Viral/genética , Animales , Secuencia de Bases , Embrión de Pollo , ADN Viral/genética , Brotes de Enfermedades/veterinaria , Egipto , Glicoproteínas/genética , Infecciones por Herpesviridae/virología , Inmunohistoquímica , Reacción en Cadena de la Polimerasa , Enfermedades de las Aves de Corral/virología , Análisis de Secuencia de ADN , Vacunas Virales/uso terapéuticoRESUMEN
The rise of bacterial resistance to antibiotics is one of the great challenges of our age. One of the strategies to limit the development of antibiotics resistance is the investigation of alternative antimicrobials. As silver nanoparticles demonstrated a potent bactericidal activity in vitro, the aim of this study was to evaluate the in vivo antibacterial activity of silver nanoparticles against Aeromonas salmonicida subsp. salmonicida. Rainbow trout (nâ¯=â¯120) were divided into four groups of 30 fish each. First group was challenged with A. salmonicida (Positive control), the second group was challenged with A. salmonicida and exposed to silver nanoparticles by immersion for three hours (100⯵g/L), the third group was challenged with A. salmonicida and intraperitoneally injected with silver nanoparticles (17⯵g/mL) and the fourth group was sham-treated and served as a negative control group. At the 7th day post challenge, histopathology of the positive control group revealed the presence of bacterial aggregates in tissues with degenerative and necrotic changes, while at the 35th day post challenge, only liver necrosis persisted. Silver nanoparticles-treated and negative control groups did not show any clinical signs, mortalities or histopathological alterations and they were tested negative for A. salmonicida. The immersion in silver nanoparticles did not result in detectable residues of silver in the muscles 35â¯days after treatment. These findings demonstrate the antibacterial properties of silver nanoparticles against A. salmonicida infection. Therefore, they could be used for development of antibacterial agents in aquaculture.
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Aeromonas salmonicida/efectos de los fármacos , Antibacterianos/farmacología , Oncorhynchus mykiss/microbiología , Plata/farmacología , Aeromonas salmonicida/crecimiento & desarrollo , Animales , Enfermedades de los Peces/tratamiento farmacológico , Infecciones por Bacterias Gramnegativas/tratamiento farmacológico , Infecciones por Bacterias Gramnegativas/veterinaria , Nanopartículas del MetalRESUMEN
BACKGROUND: Antibiotic resistance is a global issue that threatens public health. The excessive use of antibiotics contributes to this problem as the genes of antibiotic resistance can be transferred between the bacteria in humans, animals and aquatic organisms. Metallic nanoparticles could serve as future substitutes for some conventional antibiotics because of their antimicrobial activity. The aim of this study was to evaluate the antimicrobial effects of silver and zinc oxide nanoparticles against major fish pathogens and assess their safety in vitro. Silver nanoparticles were synthesized by chemical reduction and characterized with UV-Vis spectroscopy, transmission electron microscopy and zeta sizer. The concentrations of silver and zinc oxide nanoparticles were measured using inductively coupled plasma-mass spectrometry. Subsequently, silver and zinc oxide nanoparticles were tested for their antimicrobial activity against Aeromonas hydrophila, Aeromonas salmonicida subsp. salmonicida, Edwardsiella ictaluri, Edwardsiella tarda, Francisella noatunensis subsp. orientalis, Yersinia ruckeri and Aphanomyces invadans and the minimum inhibitory concentrations were determined. MTT assay was performed on eel kidney cell line (EK-1) to determine the cell viability after incubation with nanoparticles. The interaction between silver nanoparticles and A. salmonicida was investigated by transmission electron microscopy. RESULTS: The tested nanoparticles exhibited marked antimicrobial activity. Silver nanoparticles inhibited the growth of both A. salmonicida and A. invadans at a concentration of 17 µg/mL. Zinc oxide nanoparticles inhibited the growth of A. salmonicida, Y. ruckeri and A. invadans at concentrations of 15.75, 31.5 and 3.15 µg/mL respectively. Silver nanoparticles showed higher cell viability when compared to zinc oxide nanoparticles in the MTT assay. Transmission electron microscopy showed the attachment of silver nanoparticles to the bacterial membrane and disruption of its integrity. CONCLUSIONS: This is the first study on inhibitory effects of silver and zinc oxide nanoparticles towards A. salmonicida and A. invadans. Moreover, zinc oxide nanoparticles inhibited the growth of Y. ruckeri. In low concentrations, silver nanoparticles were less cytotoxic than zinc oxide nanoparticles and represent an alternative antimicrobial compound against A. hydrophila, A. salmonicida and A. invadans.
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Antibacterianos/farmacología , Enfermedades de los Peces/prevención & control , Infecciones por Bacterias Gramnegativas/veterinaria , Infecciones por Bacterias Grampositivas/veterinaria , Plata/farmacología , Óxido de Zinc/farmacología , Animales , Antibacterianos/administración & dosificación , Acuicultura , Peces , Bacterias Gramnegativas/efectos de los fármacos , Infecciones por Bacterias Gramnegativas/prevención & control , Bacterias Grampositivas/efectos de los fármacos , Infecciones por Bacterias Grampositivas/prevención & control , Técnicas In Vitro , Nanopartículas del Metal , Pruebas de Sensibilidad Microbiana , Plata/administración & dosificación , Óxido de Zinc/administración & dosificaciónRESUMEN
Nanotechnology has become an extensive field of research due to the unique properties of nanoparticles, which enable novel applications. Nanoparticles have found their way into many applications in the field of medicine, including diagnostics, vaccination, drug and gene delivery. In this review, we focused on the antimicrobial effects of nanoparticles, with particular emphasis on the problem of antibiotic resistant bacteria in fisheries. The use of nanoparticle-based vaccines against many viral pathogens is a developing field in fish medicine research. Nanoparticles have gained much interest as a specific and sensitive tool for diagnosis of bacterial, fungal and viral diseases in aquaculture. Nevertheless our review also highlights the many applications of nanotechnology that are still to be explored in fish medicine. FROM THE CLINICAL EDITOR: Advance in nanotechnology has enabled the development of nanomedicine, with many ideas being used in clinical diagnosis and therapy. In this review article, the authors described the current use of nanotechnology in fish medicine. The knowledge would also impart important information for our daily living.
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Portadores de Fármacos/química , Enfermedades de los Peces/diagnóstico , Enfermedades de los Peces/terapia , Nanopartículas/química , Animales , Infecciones Bacterianas/diagnóstico , Infecciones Bacterianas/microbiología , Infecciones Bacterianas/terapia , Infecciones Bacterianas/veterinaria , Sistemas de Liberación de Medicamentos/métodos , Enfermedades de los Peces/microbiología , Enfermedades de los Peces/virología , Peces , Técnicas de Transferencia de Gen , Nanomedicina/métodos , Nanotecnología/métodos , Vacunación/veterinaria , Virosis/diagnóstico , Virosis/terapia , Virosis/veterinaria , Virosis/virologíaRESUMEN
UNLABELLED: Silver nanoparticles (AgNPs) have wide medical applications regarding their antimicrobial effects. They are applied also in appliances such as refrigerators and washing machines. For assessment of toxicological potential of silver nanoparticles 20 mature female albino rats were divided into four groups (five rats per each). Animals were injected i/p by different doses of approximately 8.7 nm silver nanoparticles (1, 2 and 4 mg/kg b.w) daily for 28 days in addition to control group which were injected by deionized water only. Indicators of oxidative stress in liver tissue, determination of silver nanoparticles tissue concentration, description of hepatic histopathological alterations and detection of possible chromosomal aberrations in bone marrow were carried out. Results revealed various hepatic histopathological lesions that were dose dependent. The effect of Ag-NPs on hepatic malondialdhyde (MDA) and glutathione (GSH) levels were variable in different treated groups compared with the control. The tissue residues of silver nanoparticles were found in hepatic tissue and related to original treated dose. Finally, silver nanoparticles induced variable chromosomal aberrations that were dose dependent. CONCLUSION: Silver nanoparticles had the ability for inducing various hepatic histopathological alterations indicating hepatocytotoxicity presumably by oxidative stress, in addition to the induction of chromosomal aberrations in bone marrow cells denoting the genotoxicity of nanosilver particles.