title: Pathogenicity, Transmission and Antigenic Variation of H5N1 Highly Pathogenic Avian Influenza Viruses.
abstract: H5N1 highly pathogenic avian influenza (HPAI) was one of the most important avian diseases in poultry production of China, especially in Guangdong province. In recent years, new H5N1 highly pathogenic avian influenza viruses (HPAIV) still emerged constantly, although all poultry in China were immunized with H5N1 vaccinations compulsorily. To better understand the pathogenicity and transmission of dominant clades of the H5N1 HPAIVs in chicken from Guangdong in 2012, we chose a clade 7.2 avian influenza virus named A/Chicken/China/G2/2012(H5N1) (G2) and a clade 2.3.2.1 avian influenza virus named A/Duck/China/G3/2012(H5N1) (G3) in our study. Our results showed that the chickens inoculated with 10(3) EID50 of G2 or G3 viruses all died, and the titers of virus replication detected in several visceral organs were high but different. In the naive contact groups, virus shedding was not detected in G2 group and all chickens survived, but virus shedding was detected in G3 group and all chickens died. These results showed that the two clades of H5N1 HPAIVs had high pathogenicity in chickens and the contact transmission of them was different in chickens. The results of cross reactive HI assay showed that antigens of G2 and G3 were very different from those of current commercial vaccines isolates (Re-4, Re-6, and D7). And to evaluate the protective efficacy of three vaccines against most isolates form Guangdong belonging to clade 2.3.2.1 in 2012, G3 was chosen to challenge the three vaccines such as Re-4, Re-6, and D7. First, chickens were immunized with 0.3 ml Re-4, Re-6, and D7 inactivated vaccines by intramuscular injection, respectively, and then challenged with 10(6) EID50 of G3 on day 28 post-vaccination. The D7 vaccine had 100% protection against G3 for chickens, the Re-6 vaccine had 88.9%, and the Re-4 vaccine only had 66.7%. Our results suggested that the D7 vaccine could prevent and control H5N1 virus outbreaks more effectively in Guangdong. From the above, it was necessary to conduct continuously epidemiological survey and study the pathogenicity and antigenic variation of avian influenza in Southern China.
authors.affiliation: National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and ControlGuangzhou, China; Key Laboratory of Animal Vaccine Development, Ministry of AgricultureGuangzhou, China; Key Laboratory of Zoonosis Prevention and Control of GuangdongGuangzhou, China; College of Veterinary Medicine, South China Agricultural UniversityGuangzhou, China.
authors.forename: Peirong
authors.initials: P
authors.lastname: Jiao
authors.affiliation: National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and ControlGuangzhou, China; Key Laboratory of Animal Vaccine Development, Ministry of AgricultureGuangzhou, China; Key Laboratory of Zoonosis Prevention and Control of GuangdongGuangzhou, China; College of Veterinary Medicine, South China Agricultural UniversityGuangzhou, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Song
authors.affiliation: National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and ControlGuangzhou, China; Pulike Biological Engineering Inc.Luoyang, China.
authors.forename: Xiaoke
authors.initials: X
authors.lastname: Liu
authors.affiliation: National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and ControlGuangzhou, China; Key Laboratory of Animal Vaccine Development, Ministry of AgricultureGuangzhou, China; Key Laboratory of Zoonosis Prevention and Control of GuangdongGuangzhou, China; College of Veterinary Medicine, South China Agricultural UniversityGuangzhou, China.
authors.forename: Yafen
authors.initials: Y
authors.lastname: Song
authors.affiliation: Key Laboratory of Animal Vaccine Development, Ministry of AgricultureGuangzhou, China; Key Laboratory of Zoonosis Prevention and Control of GuangdongGuangzhou, China; College of Veterinary Medicine, South China Agricultural UniversityGuangzhou, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Cui
authors.affiliation: National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and ControlGuangzhou, China; Key Laboratory of Animal Vaccine Development, Ministry of AgricultureGuangzhou, China; Key Laboratory of Zoonosis Prevention and Control of GuangdongGuangzhou, China; College of Veterinary Medicine, South China Agricultural UniversityGuangzhou, China.
authors.forename: Siyu
authors.initials: S
authors.lastname: Wu
authors.affiliation: National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and ControlGuangzhou, China; Key Laboratory of Animal Vaccine Development, Ministry of AgricultureGuangzhou, China; Key Laboratory of Zoonosis Prevention and Control of GuangdongGuangzhou, China; College of Veterinary Medicine, South China Agricultural UniversityGuangzhou, China.
authors.forename: Jiaqi
authors.initials: J
authors.lastname: Ye
authors.affiliation: National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and ControlGuangzhou, China; Key Laboratory of Animal Vaccine Development, Ministry of AgricultureGuangzhou, China; Key Laboratory of Zoonosis Prevention and Control of GuangdongGuangzhou, China; College of Veterinary Medicine, South China Agricultural UniversityGuangzhou, China.
authors.forename: Nanan
authors.initials: N
authors.lastname: Qu
authors.affiliation: College of Engineering, South China Agricultural University Guangzhou, China.
authors.forename: Tiemin
authors.initials: T
authors.lastname: Zhang
authors.affiliation: National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and ControlGuangzhou, China; Key Laboratory of Animal Vaccine Development, Ministry of AgricultureGuangzhou, China; Key Laboratory of Zoonosis Prevention and Control of GuangdongGuangzhou, China; College of Veterinary Medicine, South China Agricultural UniversityGuangzhou, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Liao
keywords: H5N1; antigenic variation; pathogenicity; transmissibility; vaccine