A single dose of inactivated oil-emulsion bivalent H5N8/H5N1 vaccine protects chickens against the lethal challenge of both highly pathogenic avian influenza viruses

Mahmoud Ibrahim; Salah Zakaria; Abdel-Hamid I Bazid; Walid H Kilany; Mohamed A Zain El-Abideen; Ahmed Ali

doi:10.1016/j.cimid.2020.101601

A single dose of inactivated oil-emulsion bivalent H5N8/H5N1 vaccine protects chickens against the lethal challenge of both highly pathogenic avian influenza viruses

Comp Immunol Microbiol Infect Dis. 2021 Feb:74:101601. doi: 10.1016/j.cimid.2020.101601. Epub 2020 Nov 25.

Authors

Mahmoud Ibrahim¹, Salah Zakaria², Abdel-Hamid I Bazid³, Walid H Kilany⁴, Mohamed A Zain El-Abideen⁴, Ahmed Ali⁵

Affiliations

¹ Birds and Rabbit Medicine Department, Faculty of Veterinary Medicine, University of Sadat City, Sadat City, Minoufiya, 22857, Egypt.
² Middle East for Vaccine Company (MEVAC™), Second Industrial Area, El-Salhyia El-Gededa, Sharkia, 44671, Egypt; Virology Department, Faculty of Veterinary Medicine, University of Sadat City Sadat City, Minoufiya, 22857, Egypt.
³ Virology Department, Faculty of Veterinary Medicine, University of Sadat City Sadat City, Minoufiya, 22857, Egypt.
⁴ Reference Laboratory for Veterinary Quality Control on Poultry Production (RLQP), AHRI, ARC, 12818 Giza, Egypt.
⁵ Poultry Diseases Department, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef, 62511, Egypt. Electronic address: ahmed.ali1@vet.bsu.edu.eg.

PMID: 33307456
DOI: 10.1016/j.cimid.2020.101601

Abstract

In this study, two highly pathogenic avian influenza (HPAI) H5N8 viruses were isolated from chicken and geese in 2018 and 2019 (Chicken/ME-2018 and Geese/Egypt/MG4/2019). The hemagglutinin and neuraminidase gene analyses revealed their close relatedness to the clade-2.3.4.4b H5N8 viruses isolated from Egypt and Eurasian countries. A monovalent inactivated oil-emulsion vaccine containing a reassortant virus with HA gene of the Chicken/ME-2018/H5N8 strain and a bivalent vaccine containing same reassortant virus plus a previously generated reassortant H5N1 strain (CK/Eg/RG-173CAL/17). The safety of both vaccines was evaluated in specific-pathogen-free (SPF) chickens. To evaluate the efficacy of the prepared vaccines, 2-week-old SPF chickens were vaccinated with 0.5 mL of a vaccine formula containing 10⁸/EID₅₀ /dose from each strain via the subcutaneous route. Vaccinated birds were challenged with either wild-type HPAI-H5N8 or H5N1 viruses separately at 3 weeks post-vaccine. Results revealed that both vaccines induced protective hemagglutination-inhibiting (HI) antibody titers as early as 2 weeks PV (≥5.0 log₂). Vaccinated birds were protected clinically against both subtypes (100 % protection). HPAI-H5N1 virus shedding was significantly reduced in birds that were vaccinated with the bivalent vaccine; meanwhile, HPAI-H5N8 virus shedding was completely neutralized in both tracheal and cloacal swabs after 3 days post-infection in birds that had been vaccinated with either vaccine. In conclusion, the developed bivalent vaccine proved to be efficient in protecting chickens clinically and reduced virus shedding via the respiratory and digestive tracts. The applicability of the multivalent avian influenza vaccines further supported their value to facilitate vaccination programs in endemic countries.

Keywords: Egypt; Geese; H5N1; H5N8; HPAI; Vaccine.

MeSH terms

Animals
Chickens / immunology
Egypt
Emulsions
Influenza A Virus, H5N1 Subtype*
Influenza Vaccines*
Influenza in Birds* / prevention & control
Vaccines, Combined
Vaccines, Inactivated

Substances

Emulsions
Influenza Vaccines
Vaccines, Combined
Vaccines, Inactivated