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Updated: Mar 31, 2026
Mosquito-Associated Virus Isolation from Field-Collected Mosquitoes
Published on: August 31, 2022
Molecular and antigenic characteristics of Massachusetts genotype infectious bronchitis coronavirus in China
Lingfeng Chen1, Tingting Zhang1, Zongxi Han1
1Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150001, People's Republic of China.
Abstract:
In this study, 418 IBVs were isolated in samples from 1717 chicken flocks. Twenty-nine of the isolates were classified as the Massachusetts genotype. These 29 isolates, as well as two previously isolated Massachusetts genotype IBV strains, were studied further. Of the 31 strains, 24 were H120-like and two were M41-like isolates as determined by complete genomic sequence analysis, indicating that most of the IBV isolates were likely the reisolated vaccine virus. The remaining five IBV isolates, ck/CH/LHB/111172, ck/CH/LSD/111219, ck/CH/LHB/130598, ck/CH/LDL/110931, and ck/CH/LHB/130573, were shown to have originated from natural recombination events between an H120-like vaccine strain and other types of viruses. The virus cross-neutralization test found that the antigenicity of ck/CH/LHB/111172, ck/CH/LSD/111219, and ck/CH/LHB/130598 was similar to that of H120. Vaccination with the H120 vaccine offered complete protection against challenge with these isolates. However, isolates ck/CH/LDL/110931 and ck/CH/LHB/130573 were serotypically different from their parental viruses and from other serotypes in this study. Furthermore, vaccination with the H120 vaccine did not provide protection against challenge with these two isolates. The results of this study demonstrated that recombination is the mechanism that is responsible for the emergence of new serotype strains, and it has the ability to alter virus serotypes. Therefore, IBV surveillance of chicken flocks vaccinated with IBV live vaccines, as well as the consideration of new strategies to effectively control IBV infection using inactivated or/and genetically engineered vaccines, is of great importance.
Insights
Recombination in infectious bronchitis virus (IBV) can create new serotypes, altering vaccine effectiveness. Continuous surveillance and new vaccine strategies are crucial for controlling IBV in chicken flocks.
Area of Science:
- Veterinary Virology
- Molecular Epidemiology
- Avian Health
Background:
- Infectious Bronchitis Virus (IBV) poses a significant threat to poultry production worldwide.
- Live IBV vaccines, such as the H120 strain, are widely used for disease control.
- Understanding the evolution of IBV strains, particularly those emerging after vaccination, is critical.
Purpose of the Study:
- To investigate the origin and characteristics of IBV isolates from vaccinated chicken flocks.
- To determine the role of recombination in the emergence of novel IBV serotypes.
- To assess the efficacy of existing vaccines against newly emerged strains.
Main Methods:
- Isolation and genomic sequencing of 418 IBV samples from 1717 chicken flocks.
- Comparative analysis of genomic sequences to identify vaccine-like and recombinant strains.
- Virus cross-neutralization tests to evaluate antigenic similarity.
- Challenge studies to assess vaccine protection.
Main Results:
- Most IBV isolates were identified as re-isolated vaccine viruses (H120-like or M41-like).
- Five IBV isolates resulted from natural recombination between vaccine strains and other viruses.
- Three recombinant isolates showed similar antigenicity to H120 and were neutralized by the H120 vaccine.
- Two recombinant isolates (ck/CH/LDL/110931 and ck/CH/LHB/130573) exhibited distinct serotypes and were not controlled by the H120 vaccine.
Conclusions:
- Recombination is a key mechanism driving the emergence of new IBV serotypes.
- Novel recombinant IBV strains can evade vaccine-induced immunity.
- Enhanced IBV surveillance in vaccinated flocks and development of novel vaccine strategies (inactivated or genetically engineered) are essential for effective disease control.
