Comparative Effectiveness of Two Oil Adjuvant-Inactivated Avian Influenza H9N2 Vaccines.
Low pathogenic avian influenza H9N2 virus infection has been an important risk to the Egyptian poultry industry since 2011. Economic losses have occurred from early infection and co-infection with other pathogens. Therefore, H9N2 vaccination of broiler chicks as young as 7 days old was recommended. The current inactivated H9N2 vaccines (0.5 ml/bird) administered at a reduced dose (0.25 ml/bird) do not guarantee the delivery of an effective dose for broilers. In this study, the efficacy of the reduced-dose volume (0.3 ml/bird), compared with the regular vaccine dose (0.5 ml/bird) of inactivated H9N2 vaccines using two different commercially available adjuvants, was investigated. The vaccines were prepared from the local H9N2 virus (Ck/EG/114940v/NLQP/11) using the same antigen content: 300 hemagglutinating units. Postvaccination (PV) immune response was monitored using the hemagglutination inhibition test. At 4 wk PV, both vaccinated groups were challenged using the homologous H9N2 strain at a 50% egg infective dose (EID50) of 10(6) EID50/bird via the intranasal route. Clinical signs, mortality, and virus shedding in oropharyngeal swabs were monitored at 2, 4, 6, and 10 days postchallenge (DPC). The reduced-dose volume of vaccine induced a significantly faster and higher immune response than the regular volume of vaccine at 2 and 3 wk PV. No significant difference in virus shedding between the two vaccine formulas was found (P ≥ 0.05), and both vaccines were able to stop virus shedding by 6 DPC. The reduced-dose volume of vaccine using a suitable oil adjuvant and proper antigen content can be used effectively for early immunization of broiler chicks.
A Reference Laboratory for Veterinary Quality Control on Poultry Production (RLQP), Animal Health Research Institute, P.O. Box, 264, Dokki, Giza 12618, Egypt.
Walid H
WH
Kilany
B Virology Department, Faculty of Veterinary Medicine, Sadat City University, Menoufia 32897, Egypt.
Abdel-Hamid I
AH
Bazid
C Poultry Diseases Department, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef 65211, Egypt.
Ahmed
A
Ali
D Virology Department, Faculty of Veterinary Medicine, Cairo University, Giza 12511, Egypt.
Ayman H
AH
El-Deeb
A Reference Laboratory for Veterinary Quality Control on Poultry Production (RLQP), Animal Health Research Institute, P.O. Box, 264, Dokki, Giza 12618, Egypt.|E Middle East for Veterinary Vaccine Company, Second Industrial Area, El-Salhya El-Gededa, El-Sharqia 44671, Egypt.
Mohamed A Zain
MA
El-Abideen
E Middle East for Veterinary Vaccine Company, Second Industrial Area, El-Salhya El-Gededa, El-Sharqia 44671, Egypt.
Magdy El
ME
Sayed
C Poultry Diseases Department, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef 65211, Egypt.
Magdy F
MF
El-Kady
D000276:Adjuvants, Immunologic / Q000008:administration & dosage* / Q000737:chemistry; D000818:Animals; D002645:Chickens; D004339:Drug Compounding; D053127:Influenza A Virus, H9N2 Subtype / Q000235:genetics / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D005585:Influenza in Birds / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D011201:Poultry Diseases / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D014611:Vaccination; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000737:chemistry / Q000235:genetics / Q000276:immunology
D000276:Adjuvants, Immunologic; D007252:Influenza Vaccines; D015164:Vaccines, Inactivated
AIV; LPAI H9N2; SPF chickens; inactivated vaccine