Persistence of African swine fever virus in water and evaluation of sodium dichloroisocyanurate for viral inactivation.

Abstract

African swine fever virus (ASFV) is a highly pathogenic agent that poses a serious threat to global swine production. This study investigated the ASFV persistence in water and the virucidal efficacy of sodium dichloroisocyanurate (NaDCC). Genotype II ASFV was inoculated into sterilized field-sourced water and ultrapure water containing 0%-20% fetal bovine serum (FBS). Samples were stored at 4 ℃, 15 ℃, and 25 ℃ and monitored for up to 42 days (field-sourced water) or 154 days (ultrapure water). Infectious ASFV persisted in all field-sourced water for at least 42 days at all the tested temperatures. In ultrapure water, infectious virus remained detectable for the entire 154-day period at 4 ℃ and 15 ℃. At 25 ℃, viral inactivation was observed, yet high organic loads exerted a protective effect, extending the survival period from 56-70 days (0%-5% FBS) to 84-98 days (20% FBS). Quantitative PCR (qPCR) analysis revealed that viral genome loads remained stable. Regarding disinfection efficacy, quantitative suspension tests demonstrated that NaDCC with ≥ 500 mg/L initial available chlorine achieved effective inactivation (>4 logreduction). However, efficacy was significantly compromised at 100 mg/L, particularly at 4 ℃. These findings confirm the remarkable stability of ASFV in cold or organic-rich aquatic environments and highlight the necessity of sufficient disinfectant concentrations for effective water biosecurity.