Megalocytiviruses can propagate in cell cultures; a broblast cell line (CRF-1) derived from the tail n of red sea bream (P. major) susceptible to RSIV infection was developed. RSIV-infected CRF-1 cells showed typical morphological changes that were associated with apoptosis according to EGFP-annexin V staining. Serial viral passages were successful in CRF-1 cells according to an MTT assay [42]. In Taiwan, a similar cell line derived from the dorsal n of red sea bream was also established (i.e., RSBF-2 cells). The RSBF-2 cell line was susceptible to RSIV but produced only round and refractory cells and was then subcultured to generate a persistently infected cell line [43]. In addition, a GBC4 cell line susceptible to giant seaperch iridovirus (GSIV) was developed, and the virus titers approached 109 TCID50/mL. The suitable temperature for GSIV growth was 15°C-30°C [44]. A continuous cell culture derived from the mandarin sh fry (MFF-1) was developed [45]. MFF-1 could produce high titers of ISKNV through continuous viral passages, and these titers were conrmed through indirect immuno-uorescence (IF) assay and real-time polymerase chain reaction (quantitative PCR [qPCR]) analysis. In addition, the TK and TF cell lines derived from the kidney and n of turbot were found to be susceptible to the TRBIV isolate [46,47]. Using cell culture testing, RSIV was determined to be sensitive to acid (pH 3), chloroform, and ether. The virus was unstable when exposed to heat but stable when subjected to ultrasonic treatment, repeated freezing, and thawing in vitro [48]. Experimental infection in mandarin sh showed that ISKNV could be inactivated at pH 11 and with UV irradiation and chemicals (e.g., sodium hypochlorite and potassium

permanganate) but that iodine was not effective for viral inactivation [49].