Protective Efficacy of Recombinant Turkey Herpes Virus (rHVT-H5) and Inactivated H5N1 Vaccines in Commercial Mulard Ducks against the Highly Pathogenic Avian Influenza (HPAI) H5N1 Clade 2.2.1 Virus

In Egypt, ducks kept for commercial purposes constitute the second highest poultry population, at 150 million ducks/year. Hence, ducks play an important role in the introduction and transmission of avian influenza (AI) in the Egyptian poultry population. Attempts to control outbreaks include the use...

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Bibliographic Details
Published in:	PloS one Vol. 11; no. 6; p. e0156747
Main Authors:	Kilany, Walid H, Safwat, Marwa, Mohammed, Samy M, Salim, Abdullah, Fasina, Folorunso Oludayo, Fasanmi, Olubunmi G, Shalaby, Azhar G, Dauphin, Gwenaelle, Hassan, Mohammed K, Lubroth, Juan, Jobre, Yilma M
Format:	Journal Article
Language:	English
Published:	United States Public Library of Science 01-06-2016 Public Library of Science (PLoS)
Subjects:	Animal diseases Animals Aquatic birds Avian flu Biology and Life Sciences Chickens Disease control Disease transmission Ducks - immunology Ducks - virology Effectiveness Food H5 gene Herpes viruses Herpesviridae Herpesvirus Herpesvirus 1, Meleagrid - immunology Host-Pathogen Interactions - drug effects Host-Pathogen Interactions - immunology Immune response Infections Influenza Influenza A Virus, H5N1 Subtype - immunology Influenza A Virus, H5N1 Subtype - physiology Influenza in Birds - immunology Influenza in Birds - prevention & control Influenza in Birds - virology Influenza Vaccines - administration & dosage Influenza Vaccines - immunology Injection Inoculation Juveniles Laboratory animals Medical research Medicine and health sciences Orthomyxoviridae Outbreaks Pandemics Poultry Poultry Diseases - immunology Poultry Diseases - prevention & control Poultry Diseases - virology Protective Agents - administration & dosage Quality control Seeds Time Factors Treatment Outcome Turkeys - virology Vaccination - methods Vaccine efficacy Vaccines Vaccines, Inactivated - administration & dosage Vaccines, Inactivated - immunology Vaccines, Synthetic - administration & dosage Vaccines, Synthetic - immunology Viral Vaccines - administration & dosage Viral Vaccines - immunology Virus Shedding - drug effects Virus Shedding - immunology Viruses Waterfowl Italy Egypt Giza Egypt
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Summary:	In Egypt, ducks kept for commercial purposes constitute the second highest poultry population, at 150 million ducks/year. Hence, ducks play an important role in the introduction and transmission of avian influenza (AI) in the Egyptian poultry population. Attempts to control outbreaks include the use of vaccines, which have varying levels of efficacy and failure. To date, the effects of vaccine efficacy has rarely been determined in ducks. In this study, we evaluated the protective efficacy of a live recombinant vector vaccine based on a turkey Herpes Virus (HVT) expressing the H5 gene from a clade 2.2 H5N1 HPAIV strain (A/Swan/Hungary/499/2006) (rHVT-H5) and a bivalent inactivated H5N1 vaccine prepared from clade 2.2.1 and 2.2.1.1 H5N1 seeds in Mulard ducks. A 0.3ml/dose subcutaneous injection of rHVT-H5 vaccine was administered to one-day-old ducklings (D1) and another 0.5ml/dose subcutaneous injection of the inactivated MEFLUVAC was administered at 7 days (D7). Four separate challenge experiments were conducted at Days 21, 28, 35 and 42, in which all the vaccinated ducks were challenged with 106EID50/duck of H5N1 HPAI virus (A/chicken/Egypt/128s/2012(H5N1) (clade 2.2.1) via intranasal inoculation. Maternal-derived antibody regression and post-vaccination antibody immune responses were monitored weekly. Ducks vaccinated at 21, 28, 35 and 42 days with the rHVT-H5 and MEFLUVAC vaccines were protected against mortality (80%, 80%, 90% and 90%) and (50%, 70%, 80% and 90%) respectively, against challenges with the H5N1 HPAI virus. The amount of viral shedding and shedding rates were lower in the rHVT-H5 vaccine groups than in the MEFLUVAC groups only in the first two challenge experiments. However, the non-vaccinated groups shed significantly more of the virus than the vaccinated groups. Both rHVT-H5 and MEFLUVAC provide early protection, and rHVT-H5 vaccine in particular provides protection against HPAI challenge.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Competing Interests: The authors have declared that no competing interests exist. Conceived and designed the experiments: YMJ WHK JL MS. Performed the experiments: WHK SMM MS AS AGS MKH. Analyzed the data: WHK FOF GD OGF JL YMJ. Contributed reagents/materials/analysis tools: FOF JL YMJ WHK. Wrote the paper: WHK FOF MS SMM AS OGF AGS GD MKH JL YMJ.
ISSN:	1932-6203 1932-6203
DOI:	10.1371/journal.pone.0156747