Synergistic Inactivation of African Swine Fever Virus by a Highly Complexed Iodine Combined with Compound Organic Acids.

African swine fever (ASF) is a highly contagious disease of domestic pigs and wild boar with high morbidity and mortality caused by African swine fever virus (ASFV). Due to the lack of commercial vaccines and treatments for ASF, cleaning and disinfection remain one of the most effective biosecurity measures to control ASF. Our previous studies have shown that ASFV can be inactivated by 0.25 to 5% highly complexed iodine (HPCI) in 5 to 30 min. This study evaluated the synergistic inactivation effects of HPCI combined with compound organic acids (COAs) against ASFV. The results showed that the inactivation rates of HPCI, COAs, and HPCI+COAs on the reporter ASFV expressing the green fluorescent protein increased in dose- and time-dependent manners. The best inactivation effects were obtained when the compatibility ratio of HPCI and COAs was 5:1, and the ideal temperature was 25°C. Furthermore, there were no significant differences when comparing the efficacy of HPCI combined with COAs (HPCI+COAs) in inactivating wild-type ASFV and the reporter ASFV (P > 0.05). ASFV of 104.0 50% tissue culture infective dose (TCID50)/mL was completely inactivated by 0.13% HPCI (0.0065% effective iodine), 0.06% COAs, or 0.13% HPCI+COAs (approximately 0.0054% effective iodine), respectively, while 106.0 TCID50/mL ASFV was completely inactivated by 1.00% HPCI (0.05% effective iodine), 0.50% COAs, or 1.00% HPCI+COAs (0.042% effective iodine), respectively. It was found that the combination index (CI) of HPCI and COAs was less than 1 under different conditions. This study demonstrated that HPCI+COAs could synergistically inactivate ASFV and represent an effective compound disinfectant for the control of ASF. IMPORTANCE African swine fever (ASF) is a highly contagious disease of swine with high morbidity and mortality caused by African swine fever virus (ASFV). Due to the lack of commercial vaccines and treatment available for ASF, effective disinfectants and the proper use of them are essential to inactivate ASFV. The significance of this research is in searching for an ideal disinfectant that has the advantages of low toxicity and nonpollution and can inactivate ASFV efficiently. In this study, we demonstrated that HPCI+COAs had synergistic effects on inactivating ASFV. Thus, HPCI+COAs could be used as an effective disinfectant for the control of ASF.