Virucidal effects of various agents—including protease—against koi herpesvirus and viral haemorrhagic septicaemia virus

Abstract

In a search for alternative, environmentally friendly and effective disinfecting agents, a commercially available protease—Neutrase®—was tested in this work for inactivation of koi herpesvirus (KHV) and of viral haemorrhagic septicaemia virus (VHSV). For comparison, the stability of these viral pathogens in similar configurations at various pH values and concentrations of peracetic acid or quicklime, typically used for disinfection, was tested. Therefore, virus suspensions were incubated with various concentrations of different agents for 24 hr and the titre of the remaining infectious particles was determined by virus titration. Furthermore, the treatment of both viruses, with the agents at concentrations that were previously appointed as effective, was also examined in the presence of solid material (quartz sand). All procedures investigated in this study, including the protease treatment, were able to reduce the titre of KHV and VHSV below the detection limit of the titration. Although further studies are necessary, this is the first report of the application of a protease for the inactivation of the selected fish pathogens, demonstrating the great potential of the latter for disinfection.

Stability of viral haemorrhagic septicaemia virus, infectious hematopoietic necrosis virus and cyprinid herpesvirus 3 in various water samples

“…It cannot be ruled out that the faster inactivation of CyHV-3 in the filtered sample from a carp pond registered here might be connected to the higher pH value of this water in comparison with other tested samples. On the other hand, in a previous study of our group no reduction of the CyHV-3 titre was observed at pH values between 5 and 9 within 24 hr in cell culture medium (Amtmann et al, 2019), but longer incubation at a pH around 9 was not tested and therefore the influence to the infectivity of CyHV-3 cannot be excluded.…”

“…Furthermore, these two bacterial genera are known to produce metalloproteases (Janda & Abbott, 2010;Wandersman, 1989) that can contribute to the degradation of envelope proteins of viruses, thereby inactivating them. In our previous work, a reduction of 3 and 4 log steps within 24 hr of CyHV-3 and VHSV titres, respectively, could be achieved by the application of Neutrase ® , a metalloendoprotease from Bacillus amyloliquefaciens, to the samples (Amtmann et al, 2019). Thus, it was demonstrated that a correlation exists between a proteolytic enzyme belonging to metalloendoproteases and the decrease in titres of these two fish viruses.…”

In-vitro Virucidal Activity of Commercial Enzyme Preparations against SARS-CoV-2 Virus

“…The enzyme preparations used for this study contain proteases and lipases as major components, in addition to other enzymes. Proteases and lipases from other sources have demonstrated virucidal effects in previous studies [6,7,8,9 ]. The mechanism of inactivation of the virus under study could be mediated by the catalytic action of the enzymes on the virion structure or the disruption of the receptors used for gaining entry into the host cell.…”

“…Yamaguchi et al [6] have explored the virucidal effects of glucose oxidase and peroxidase on HIV-type 1. Amtmann et al [7] have demonstrated the virucidal effects of protease against koi herpesvirus and viral haemorrhagic septicaemia virus. Gudmundsdottir et al [8], have reported a medical device mouth spray containing cod trypsin, a proteolytic enzyme, against the common cold.…”

Inhibitory properties of microalgal extracts on thein vitroreplication of cyprinid herpesvirus 3

“…Infectious CyHV-3 viral particles were estimated using the endpoint dilution assay (50 % tissue culture infective dose assay, TCID50) as outlined by Reed & Muench (1938) and described previously by Mletzko et al (2017) as well as Amtmann et al (2020). The virus titer was registered as TCID50 mL -1 .…”