Qiu, H.-J. | bioRxiv Science

bioRxiv2022

Efficient 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 with high morbidity and mortality caused by African swine fever virus (ASFV). Cleaning and disinfection remain one of the most effective biosecurity measures to prevent and control the spread of ASFV. In this study, we evaluated the inactivation effects of highly complexed iodine (HPCI) combined with compound organic acids (COAs) against ASFV under different conditions. The results showed that the inactivation rates of the disinfectants on the reporter ASFV increased in dose- and time-dependent manners, the best inactivation effects were obtained when the compatibility ratio of HPCI and COAs was 5:1 at 25{degrees}C. Furthermore, there were no significant differences by 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 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. Therefore, HPCI+COAs had synergistic effects to inactivate ASFV. This study demonstrated that HPCI+COAs could rapidly and efficiently inactivate ASFV and represent an effective compound disinfectant for the control of ASF. IMPORTANCEAfrican swine fever (ASF) is a highly contagious disease 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 extremely essential to inactivate ASFV. The significance of this research is in searching for an ideal disinfectant that not only has the advantages of low toxicity and non-pollution but also can inactivate ASFV rapidly and efficiently. In this study, we proved that HPCI+COAs not only exhibited low cytotoxicity, but also could completely inactivate ASFV within 5 min at 4{degrees}C, 25{degrees}C and 37{degrees}C. In addition, HPCI+COAs had synergistic effects on inactivated ASFV. Thus, HPCI +COAs could be used as an effective disinfectant for the control of ASF.

microbiology↗

bioRxiv2020

The Genetic Variation Landscape of African Swine Fever Virus Reveals Frequent Positive Selection on Amino Acid Replacements

African swine fever virus (ASFV) is a lethal disease agent that causes high mortality in swine population and devastating loss in swine industries. The development of efficacious vaccines has been hindered by the gap in knowledge concerning genetic variation of ASFV and the genetic factors involved in host adaptation and virus-host interactions. In this study, we performed a meta-genetic study of ASFV aiming to profile the variation landscape and identify genetic factors with signatures of positive selection and relevance to host adaptation. Our data reveals a high level of genetic variability of ASFV shaped by both diversifying selection and selective sweep. The selection signatures are widely distributed across the genome with the diversifying selection falling within 29 genes and selection sweep within 25 genes, highlighting strong signals of adaptive evolution of ASFV. Further examination of the sequence properties reveals the link of the selection signatures with virus-host interactions and adaptive flexibility. Specifically, we discovered a site at 157th of the key antigen protein EP402R under diversifying selection, which is located in the cytotoxic T-cell epitope related with the low level of cross-reaction in T-cell response. Importantly, two multigene families MGF360 and MGF505, the host range factors of ASFV, exhibit divergent selection among the paralogous members, conferring sequence pools for genetic diversification and adaptive capability. By integrating the genes with selection signatures into a unified framework of interactions between ASFV and hosts, we showed that the genes are involved in multiple processes of host immune interaction and virus life cycles, and may play crucial roles in circumventing host defense systems and enhancing adaptive fitness. Our findings will allow enhanced understanding of genetic basis of rapid spreading and adaptation of ASFV among the hosts.

evolutionary biology↗