Establishment and application of PCR method for typing large yellow croaker iridovirus
Large yellow croaker iridovirus diseases caused by large yellow croaker iridovirus (LYCIV) is one of the main epidemic dis-eases during high temperature period in summer, which causes huge economic losses to large yellow croaker industry. Early diagnosis is important for the prevention and treatment of the disease. By designing a pair of specific primers from the ORF026 region of the genome sequence of LYCIV, a PCR detection method for different types of LYCIV was established, which can effectively identify two subtypes of LYCIV: RSIV-Ia and RSIV-Ib subtypes. The method was highly specific for the detection of RSIV-Ib subtype, and had no cross-reaction against the other pathogens such as red sea bream iridovirus, grouper iridovirus in genus Ranavirus, Mandarin ranavirus, yellow fin bream iridovirus and koi herpesvirus. The detection sensitivity is high, which can reach 102copies/uL. Based on the detection results of 19 clinical positive samples from Ningde large yellow croaker cultured area, 15 samples were RSIV-Ia subtype and 4 samples were RSIV-Ib subtype, indicating that the method can effectively distinguish two different subtypes of large yellow croaker iridovirus.