Errors generated during the genomic replication of IBV and the selective pressure following the use of live attenuated vaccines or multiple infections with different IBV serotypes has led to the emergence of numerous IBV variants [7], [8]. In particular, small change as little as 5% in the amino acid composition of S1 gene may lead to alteration in cross protection among closely related serotypes [9]. In China, IBV was first observed during the early 1980s, and outbreaks have since been frequently reported [7]. The QX-like genotype is thought to have originated during the mid-1990s and continues to be the predominant strain, whereas the LDT3, 4/91, and Taiwan subtypes have also recently been frequently isolated in China [10], [11], [12], [13]. Severe nephritis, false layer syndrome, and high mortality are observed in chickens infected with this viral genotype, which represents a major problem in the poultry industry, particularly in China.