Vaccination of chickens decreased Newcastle disease virus contamination in eggs.

In this study, hens were sham-vaccinated or received one or two doses of inactivated LaSota vaccine, followed three weeks later by virulent Newcastle disease virus challenge. Eggs were collected daily and shell, albumen, and yolk were subjected to virus isolation, as were oral and cloacal swabs at 2 and 4 days post-challenge (dpc). A second experiment evaluated the distribution of the virus in the reproductive tract of non-vaccinates. All vaccinated chickens survived challenge, and the levels of virus shed from cloacal swabs were decreased significantly when compared to shams. In non-vaccinated hens, virus was detected in the ovary and all segments of the oviduct. Yolk, albumen and eggshell surface from eggs laid at day 4 and 5 post-infection by sham-vaccinated hens were positive for NDV, but eggs from LaSota vaccinated hens lacked virus in internal egg components (i.e. yolk and albumen) and had reduction in the number of positive eggshell surfaces. These results indicate virulent NDV can replicate in the reproductive tract of hens and contaminate internal components of eggs and eggshell surface, but vaccination was able to prevent internal egg contamination, reducing eggshell surface contamination, and reducing shedding from digestive and respiratory tracts in virulent NDV challenged hens. PMID: 26503831 [PubMed - as supplied by publisher]
Source: Avian Pathology - Category: Pathology Authors: Tags: Avian Pathol Source Type: research

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This study demonstrates the usefulness of the HPAI H5N1 HA2 E29 epitope as a DIVA antigen in HPAI H5N1 vaccinated and infected chickens.Research Highlight E29 (HA2 position 488-516) epitope is antigenic in chickenAntibodies to E29 are elicited following live H5N1 virus infection in chickenE29 epitope is a potential DIVA antigen for use in ELISA. PMID: 31738584 [PubMed - as supplied by publisher]
Source: Avian Pathology - Category: Pathology Authors: Tags: Avian Pathol Source Type: research
CONCLUSION: We report on an assay to measure stem-specific ADCC activity using SS np probes. Our results indicate high prevalence of HA-stem antibodies with cross-reactive ADCC activity. Such assay could be utilized in the assessment of next generation influenza vaccines. PMID: 31735504 [PubMed - as supplied by publisher]
Source: Vaccine - Category: Allergy & Immunology Authors: Tags: Vaccine Source Type: research
ss TM Abstract Highly pathogenic H5N1 influenza viruses continue to spread around the globe and reassort with low pathogenic avian influenza viruses often resulting in morbidity and mortality to not only waterfowl, but also poultry. Our group previously developed two hemagglutinin (HA) based vaccines using a methodology termed computationally optimized broadly reactive antigen (COBRA). Each of these HA antigens, Human COBRA 2 (Hu-CO) and Human-Avian COBRA 2 (Hu-Av CO) elicit antibodies with hemagglutination-inhibition (HAI) activity against viruses from various clades, but not always the same viruses. Here, we hav...
Source: Vaccine - Category: Allergy & Immunology Authors: Tags: Vaccine Source Type: research
Abstract BACKGROUND: We have previously developed a recombinant avian avulavirus serotype 10 (rAAvV-10/HA) expressing the hemagglutinin (HA) gene of a highly pathogenic avian influenza virus (HPAIV) as an emergency vaccine for poultry. rAAvV-10/HA can overcome the activity of the anti-AAvV-1 (Newcastle disease virus) antibody acquired by commercial chickens upon routine vaccination. Most chickens do not have the anti-AAvV-10 antibody, which could interfere with the vaccine efficacy. However, the vaccine efficacy of rAAvV-10/HA is not satisfactory in chickens even though it affords protection against an HPAIV chall...
Source: Vaccine - Category: Allergy & Immunology Authors: Tags: Vaccine Source Type: research
AbstractDespite the fact that vaccine resistance has been typically considered a rare phenomenon, some episodes of vaccine failure have been reported with increasing frequency in intensively-raised livestock. Infectious bronchitis virus (IBV) is a widespread avian coronavirus, whose control relies mainly on extensive vaccine administration. Unfortunately, the continuous emergence of new vaccine-immunity escaping variants prompts the development of new vaccines. In the present work, a molecular epidemiology study was performed to evaluate the potential role of homologous vaccination in driving IBV evolution. This was undert...
Source: Veterinary Research - Category: Veterinary Research Source Type: research
This study reports the molecular characterisation of a GaHV-2 strain detected in a flock of Italian meat-type turkeys exhibiting visceral lymphomas. Sequencing and phylogenetic analysis of the meq gene revealed that the turkey GaHV-2 has molecular features of high virulence and genetic similarity with GaHV-2 strains recently detected in Italian commercial and backyard chickens. GaHV-2 is ubiquitous among chickens despite the vaccination, and chicken-to-turkey transmission is hypothesised due to the presence of broilers in neighbouring pens.Research highlights A GaHV-2 strain from Italian turkeys was molecularly characteris...
Source: Avian Pathology - Category: Pathology Authors: Tags: Avian Pathol Source Type: research
In conclusion, the present study provides the evidence for a ubiquitous distribution of ARV infection in Egypt as well as represents a starting point for genetic characterization of the currently circulating ARV strains.
Source: Tropical Animal Health and Production - Category: Veterinary Research Source Type: research
tego J, Calvo-Pinilla E Abstract African horse sickness virus (AHSV) is an insect-borne pathogen that causes acute disease in horses and other equids. In an effort to improve the safety of currently available vaccines and to acquire new knowledge about the determinants of AHSV immunogenicity, new generation vaccines are being developed. In this work we have generated and tested a novel immunization approach comprised of nonstructural protein 1 (NS1) of AHSV serotype 4 (AHSV-4) incorporated into avian reovirus muNS protein microspheres (MS-NS1) and/or expressed using recombinant modified vaccinia virus Ankara vecto...
Source: Vaccine - Category: Allergy & Immunology Authors: Tags: Vaccine Source Type: research
Abstract BACKGROUND: The emergence and spread of highly pathogenic avian influenza (H5N1) viruses have raised global concerns of a possible human pandemic, spurring efforts towards H5N1 influenza vaccine development and improvements in vaccine administration methods. We previously showed that a prime-boost vaccination strategy induces robust and broadly cross-reactive antibody responses against the hemagglutinin globular head domain. Here, we specifically measure antibodies against the conserved hemagglutinin stem region in serum samples obtained from the prior study to determine whether stalk-reactive antibodies ...
Source: Vaccine - Category: Allergy & Immunology Authors: Tags: Vaccine Source Type: research
This study provides a strategy for the efficient production of IBDV vaccines and could potentially be utilized to improve the production of other viral vaccines and biologics.
Source: Journal of Biotechnology - Category: Biotechnology Source Type: research
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