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Eight isolates of infectious bronchitis virus (IBV) were obtained from various prefectures in Japan during 2003-2007 and were genetically analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR) coupled with direct sequencing. These IBV isolates were classified into three genetic groups, including two that have already been reported (JP-I and JP-III). The remaining group is related to the 4/91 (also known as 793/B) type, prevalent mainly in European countries, and has not been identified in Japan until now.
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Mase et al. (2008) studied this question.
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