Virucidal efficacy of chlorine-based disinfectant cleaner against Bombyx mori nucleopolyhedrovirus, BmNPV, under load condition
2020
Nozawa, M.
Virucidal efficacy of chlorine-based disinfectant cleaner against Bombyx mori nucleopolyhedrovirus, BmNPV, under load condition was verified by suspension test followed by a silkworm-use bioassay. In this research, each of test suspensions was reacted at 25℃ for 10 min in a sterilized tube (15 ml) at the mixing ratio of 1 g of sterilized dust from a mounting room, 1 ml of BmNPV occlusion bodies (1.15×10E9 OBs/ml) and 9 ml of each disinfectant. After the treatment, the bioassay using newly molted 2nd-instar larvae of silkworm was performed by an oral inoculation method. In this assay, thirty larvae were placed on a square slice of semi-artificial diet (4 cm×4 cm, 0.1 cm thickness) on which 0.4 ml of reacted solution was dropped equally, and allowed to feed the diets for 24h at 25℃ under 16L:8D. After the feeding, the larvae were reared with fresh diets for six days under the same condition. Comparison of virucidal efficacy between chlorine-based “Disinfectant Cleaner for Sericulture(DCS)” and 3% (v/v) formaldehyde, based on the number of larvae died of nucleopolyhedrosis checked on the final day of the bioassay, revealed that the DCS solution which was composed of sodium hypochlorite (NaOCl) containing 251 ppm of free available chlorine, 0.5% (w/v) sodium carbonate (Na2CO3) and 0.2% (w/v) sodium tetrapolyphosphate (Na6P4O13) had almost the same efficacy as 3% formaldehyde against BmNPV, and this result indicated that the DCS solution would be available for disinfection and cleaning process in mounting room of sericultural farms.
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