Seroprevalence and genotyping of avian infectious bronchitis virus detected from Iranian unvaccinated backyard chickens
Background and Objectives: Different epidemiological studies have found that backyard chickens are a reservoir for poultry diseases. Most backyard chicken flocks have a poor level of biosecurity, which increases the risk of spread of diseases. In recent years, the number of backyard chickens has been on the rise in Iran. However, the health status of backyard flocks is still poorly documented. Thus, this study aimed at examining the seroprevalence of antibodies against infectious bronchitis virus (IBV) and molecular surveillance and genotyping of IBV among backyard chickens (without vaccination history) in Mazandaran province, North of Iran, 2014. Materials and Methods: A total of 460 blood samples of unvaccinated backyard chickens in the mentioned area were tested for antibodies against IBV using commercial ELISA. Also, cecal tonsils were collected from 75 chickens in the same area. Real time RT-PCR (for detection) and RT-PCR and sequencing spike gene were performed. Results: The seropositivity rate was 54.5%. In addition, we detected 793/B, Variant 2, and QX in the backyard flocks and performed phylogenetic studies on them. The phylogenetic study revealed that the detected genotypes had high homology with IBV strains that were infected broilers, pullets, and layers in Iran. Conclusion: There is a need for continuous monitoring of IBV among avian species to complete the epidemiological map and work on the pathogenesis of Iranian IBV strains in Iranian backyard chickens.
Infectious bronchitis virus variants: a review of the history, current situation and control measures
The history, current situation and control measures for infectious bronchitis virus (IBV) variants are reviewed. A large number of IBV variants exist worldwide; some being unique to a particular area, others having a more general distribution. The possible reasons why some strains spread readily over major parts of the world, whereas other strains stay more localized are discussed. The advantages and disadvantages of strain classification by protectotyping, serotyping and genotyping are discussed in relation to in vivo protection. The different vaccination strategies are also considered.
Isolation of infectious bronchitis virus from broiler chickens in Chile.
An infectious-bronchitis-like virus was isolated from 6-week-old broiler chickens unvaccinated with infectious bronchitis virus (IBV). The isolate produced lesions in embryonating chicken eggs (ECE) and clinical signs in birds characteristic of IBV. Serum-neutralization and agar-gel diffusion tests demonstrated the serological relationship of this isolate to IBV.