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 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.
Reference Laboratory for Veterinary Quality Control on Poultry Production (NLQP), Animal Health Research Institute, P.O. Box, 264, Giza, Egypt.
Walid H
WH
Kilany
Reference Laboratory for Veterinary Quality Control on Poultry Production (NLQP), Animal Health Research Institute, P.O. Box, 264, Giza, Egypt.
Marwa
M
Safwat
Reference Laboratory for Veterinary Quality Control on Poultry Production (NLQP), Animal Health Research Institute, P.O. Box, 264, Giza, Egypt.|Food and Agriculture Organization of the United Nations (FAO)-Emergency Center of Transboundary Animal Diseases (ECTAD), P.O. Box, 2223, Giza, Egypt.
Samy M
SM
Mohammed
Reference Laboratory for Veterinary Quality Control on Poultry Production (NLQP), Animal Health Research Institute, P.O. Box, 264, Giza, Egypt.
Abdullah
A
Salim
Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, South Africa.
Folorunso Oludayo
FO
Fasina
Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, & Department of Animal Health, Federal College of Animal Health and Production Technology, Ibadan, Nigeria.
Olubunmi G
OG
Fasanmi
Reference Laboratory for Veterinary Quality Control on Poultry Production (NLQP), Animal Health Research Institute, P.O. Box, 264, Giza, Egypt.
Azhar G
AG
Shalaby
Food and Agriculture Organization (FAO) Viale delle Terme di Caracalla, 00153 Rome, Italy.
Gwenaelle
G
Dauphin
Reference Laboratory for Veterinary Quality Control on Poultry Production (NLQP), Animal Health Research Institute, P.O. Box, 264, Giza, Egypt.
Mohammed K
MK
Hassan
Food and Agriculture Organization (FAO) Viale delle Terme di Caracalla, 00153 Rome, Italy.
Juan
J
Lubroth
Food and Agriculture Organization of the United Nations (FAO)-Emergency Center of Transboundary Animal Diseases (ECTAD), P.O. Box, 2223, Giza, Egypt.
Yilma M
YM
Jobre
D000818:Animals; D004372:Ducks / Q000276:immunology* / Q000821:virology; D026002:Herpesvirus 1, Meleagrid / Q000276:immunology*; D054884:Host-Pathogen Interactions / Q000187:drug effects / Q000276:immunology; D053124:Influenza A Virus, H5N1 Subtype / Q000276:immunology* / Q000502:physiology; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D005585:Influenza in Birds / Q000276:immunology / Q000517:prevention & control / Q000821:virology; D011201:Poultry Diseases / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D020011:Protective Agents / Q000008:administration & dosage; D013997:Time Factors; D016896:Treatment Outcome; D014422:Turkeys / Q000821:virology; D014611:Vaccination / Q000379:methods; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000276:immunology; D014765:Viral Vaccines / Q000008:administration & dosage / Q000276:immunology*; D017201:Virus Shedding / Q000187:drug effects / Q000276:immunology
D007252:Influenza Vaccines; D020011:Protective Agents; D015164:Vaccines, Inactivated; D014614:Vaccines, Synthetic; D014765:Viral Vaccines