Natural oil blend formulation as an anti-African swine fever virus agent in in vitro primary porcine alveolar macrophage culture

Abstract

Background and Aim: African swine fever is one of the severe pathogens of swine. It has a significant impact on production and economics. So far, there are no known remedies, such as vaccines or drugs, reported working successfully. In the present study, the natural oil blend formulation's (NOBF) efficacy was evaluated against ASFV in vitro using porcine alveolar macrophages (PAMs) cells of swine. Materials and Methods: The capacity of NOBF against the ASFV was tested in vitro. The NOBF combines Eucalyptus globulus, Pinus sylvestris, and Lavandula latifolia. We used a 2-fold serial dilution to test the NOBF formulation dose, that is, 105 HAD50/mL, against purified lethal dose of African swine in primary PAMs cells of swine. The PAM cells survival, real-time polymerase chain reaction (PCR) test, and hemadsorption (HAD) observation were performed to check the NOBF efficacy against ASFV. Results: The in vitro trial results demonstrated that NOBF up to dilution 13 or 0.000625 mL deactivates the lethal dose 105 HAD50 of ASFV. There was no HAD (Rosetta formation) up to dilution 12 or 0.00125 mL of NOBF. The Ct value obtained by running real-time PCR of the NOBF group at 96 h post-infection was the same as the initial value or lower (25), whereas the Ct value of positive controls increased several folds (17.84). Conclusion: The in vitro trial demonstrated that NOBF could deactivate the ASFV. The NOBF has the potential to act as anti-ASFV agent in the field. The next step is to conduct in vivo level trial to determine its efficacy.

In vitro cytotoxicity and virucidal efficacy of potassium hydrogen peroxymonosulfate compared to quaternary ammonium compound under various concentrations, exposure times and temperatures against African swine fever virus

“…We evaluated virucidal efficacy using the cytopathic effect on infected cells demonstrated by pig red blood cell adsorption around PAM cells, also called HAD or rosette formation [17][18][19]. Several researchers have used this characteristic to indicate the presence of ASFV in the tissue culture [10,11].…”

<i>In vitro</i> primary porcine alveolar macrophage cell toxicity and African swine fever virus inactivation using five commercially supply compound disinfectants under various condition

“…Indicator or cytopathic effects or infected cell observation, is the ability to adsorb pig red blood cells around PAM cells, namely, hemadsorption (HAD) or rosette formation, as shown in Fig 2.Several researchers have demonstrated that infected cells with wildtype of ASFV could absorb pig red blood cells, called hemadsorption[3,7,21] and Kouam et al[10] and Revilla et al[14] have described pig red blood cells around infected swine monocytes, namely rosettes formations, are both characteristic features of ASFV-infected cells.…”

“…In addition, pig red blood cells (GE Healthcare, New York, NY, USA), were consumed and kept in a maintenance medium containing RPMI 1640 medium and 1% penicillin-streptomycin solution and stored at 4°C prior to testing. The ASFV, namely VNUA-ASFV-L01/HN/04/19, was propagated using primary PAM cells [ 21 ]. After harvesting, the virus was aliquoted and kept at −80°C until testing.…”

“…After that, the mixture was diluted as a 10-fold serial dilution using the maintenance medium and inoculated into PAM cells for virus recovery. To these treatments was added the maintenance medium supplemented with 2% pig red blood cells and incubated into a 5% CO 2 incubator, as described [ 3 , 8 , 21 ]. A massive cytopathic effect, namely HAD or rosette formation, was observed using an inverted microscope twice a day for five days.…”

“… . Several researchers have demonstrated that infected cells with wildtype of ASFV could absorb pig red blood cells, called hemadsorption [ 3 , 7 , 21 ] and Kouam et al . [ 10 ] and Revilla et al .…”