Genetic Analysis of Avian Reovirus Isolated from Chickens in Japan.

Sigma C protein-coding sequences have been used to phylogenetically classify avian reovirus (ARV) strains. However, the relationship between serotype and phylogenetic cluster classification of the five prototype serotype strains of ARV in Japan has not been established. Thus, we used sigma C protein-coding sequences to characterize avian reoviruses (ARVs) isolated from chickens with tendonitis in Japan together with the five prototype serotype strains of ARV in Japan. Phylogenetic analysis of ARVs based on the sigma C protein-coding sequences revealed that the five prototype serotype strains of ARV were each classified into different, independent clusters. Two field isolates (JP/Tottori/2016 and JP/Nagasaki/2017) that were isolated from chickens with arthritis/tenosynovitis were classified into different clusters. JP/Tottori/2016 was classified into cluster VI with the CS-108 strain, and JP/Nagasaki/2017 was classified into cluster I with strain TS-142. Serologically, JP/Tottori/2016 was well-neutralized by antisera against the CS-108 strain, whereas JP/Nagasaki/2017 cross-reacted with antisera against both the CS-108 and TS-142 strains. Embryo lethality test revealed that the two field isolates induced 80% and 67% embryo mortality, respectively, whereas the five prototype strains induced 0%-33% embryo mortality. Our findings will contribute to understanding the characteristics of ARV strains in Japan.

Nota de investigación­Análisis genético de reovirus aviares aislados de pollos en Japón. Se han utilizado secuencias de proteína Sigma C para clasificar filogenéticamente cepas de reovirus aviar (ARV). Sin embargo, no se ha establecido la relación entre el serotipo y la clasificación de grupos filogenéticos de las cinco cepas prototipo de serotipo de reovirus aviares en Japón. Por lo tanto, se utilizó la secuenciación de la proteína sigma C para caracterizar los reovirus aviares (ARV) aislados de pollos con tendinitis en Japón junto con las cinco cepas prototipos de serotipos de reovirus aviares en Japón. El análisis filogenético de los reovirus extranjeros basado en el gene sigma C reveló que las cinco cepas prototipo de serotipo de reoviruses se clasificaron cada una en grupos diferentes e independientes. Dos aislamientos de campo (JP/Tottori/2016 y JP/Nagasaki/2017) que se aislaron de pollos con artritis/tenosinovitis se clasificaron en diferentes grupos. El aislamiento JP/Tottori/2016 se clasificó en el grupo VI con la cepa CS-108, y el aislamiento JP/Nagasaki/2017 se clasificó en el grupo I con la cepa TS-142. Serológicamente, el aislamiento JP/Tottori/2016 fue completamente neutralizado por antisueros contra la cepa CS-108, mientras que el virus JP/Nagasaki/2017 reaccionó de forma cruzada con antisueros contra las cepas CS-108 y TS-142. Las pruebas de patogenicidad de embriones revelaron que los dos aislados de campo indujeron 80% y 67% de mortalidad embrionaria, respectivamente, mientras que las cinco cepas prototipo indujeron 0% -33% de mortalidad embrionaria. Estos hallazgos contribuirán a comprender las características de las cepas de reovirus aviares en Japón.

Genotyping of infectious bronchitis viruses isolated in Japan during 2008-2019.

Seventeen isolates of infectious bronchitis virus (IBV) were obtained from various prefectures of Japan during 2008-2019 and genetically analyzed. The IBV isolates were classified into six genetic groups, based on phylogenetic analysis of the S1 gene. The S1 genotypes were distinguishable by a newly developed restriction fragment length polymorphism (RFLP) method using three endonucleases, Hae II, Hpa I, and Fok I. Moreover, the isolates were classified into four genetic groups, based on phylogenetic analysis of the S2 gene. However, novel genetic groups based on a combination of S1 and S2 genotypes, which were undetected previously, were confirmed in this study, indicating that various recombinant IBV strains were prevalent in poultry in Japan.