Abstract
Optimum methods for evaluating virucidal activities of germicides to infectious pancreatic necrosis virus (IPNV) and infectious hematopoietic necrosis virus (IHNV) were studied.
1. Among the fish cell lines examined CHSE-214 and EPC cells were best suited for examining virucidal activities.
2. Cell-associated virus suspension (CAV) was effectively obtained by freezing and thawing cell-sheet culture just before the appearance of cytopathological effects (CPE).
3. CAV of IPNV did not change in infectivity titer during the stocking period of 8 weeks at either -20°C or -80°C. However, infectivity titer of IHNV in CAV significantly decreased infectivity titer at both -20°C and -80°C.
4. Virucidal activities of IPNV and IHNV did not change during 6 h incubation at temperatures from 10°C to 37°C and from 10°C to 15°C, respectively. Hence, 15°C appears to be a reasonable temperature for routine use in this assay system.
5. Toxicities to IPNV and IHNV of germicides other than halogenic compounds were successfully eliminated by 102-105 dilutions of PBS (-).
