Log10 TCID50 Research Articles

Berbamine Hydrochloride Inhibits African Swine Fever Virus Infection In Vitro

African swine fever virus (ASFV) causes a viral disease in swine with a mortality rate of approximately 100%, threatening the global pig industry's economic development. However, vaccines are not yet commercially available, and other antiviral therapeutics, such as antiviral drugs, are urgently needed. In this study, berbamine hydrochloride, a natural bis-benzylisoquinoline alkaloid isolated from the traditional Chinese herb Berberis amurensis, showed significant antiviral activity against ASFV. The 50% cytotoxic concentration (CC50) of berbamine hydrochloride in porcine alveolar macrophages (PAMs) was 27.89 μM. The antiviral activity assay demonstrated that berbamine hydrochloride inhibits ASFV in a dose-dependent manner. In addition, a 4.14 log TCID50 decrease in the viral titre resulting from non-cytotoxic berbamine hydrochloride was found. Moreover, the antiviral activity of berbamine hydrochloride was maintained for 48h and took effect at multiplicities of infection (MOI) of 0.01, 0.1, and 1. The time-of-addition analysis revealed an inhibitory effect throughout the entire virus life-cycle. A subsequent viral entry assay verified that berbamine hydrochloride blocks the early stage of ASFV infection. Moreover, similar anti-ASFV activity of berbamine hydrochloride was also found in PK-15 and 3D4/21 cells. In summary, these results indicate that berbamine hydrochloride is an effective anti-ASFV natural product and may be considered a novel antiviral drug.

Preclinical studies of antiviral activity of the RPH-137 fusion protein and molnupiravir against COVID-19

Finding effective and safe medicines to fight SARS-CoV-2 infection is an urgent task. RPH-137 is an original trap fusion protein against SARS-CoV-2 virus. It comprises the angiotensin-converting enzyme type 2 extracellular domain and the human IgG1 Fc fragment.The aim of the study was to carry out a preclinical evaluation of the efficacy of RPH-137 and molnupiravir against SARS-CoV-2 infection.Materials and methods: the authors analysed RPH-137 expressed in a stable CHO cell line and molnupiravir used as an active pharmaceutical ingredient. Drug-mediated inhibition of virus-induced cytotoxicity was assessed in Vero cell culture. In vivo efficacy assessments were performed in Syrian hamsters. The animals were infected intranasally with SARS-CoV-2 (PIK35 clinical isolate) in the dose of 5 log TCID50. The authors evaluated body weight measurements, lung–body weight ratios, and lung histopathology findings and determined viral RNA levels in oropharyngeal swabs by RT-PCR using the amplification cycle threshold (Ct). The statistical analyses involved one- and two-way ANOVA, Student's t-test, and Mann–Whitney test.Results: RPH-137 and molnupiravir inhibited the cytopathic effect of SARS-CoV-2 in Vero cells; the EC50 values of RPH-137 amounted to 4.69 μg/mL (21.3 nM) and 16.24 μg/mL (73.8 nM) for 50 TCID50 and 200 TCID50, respectively, whereas the EC50 values of molnupiravir were 0.63 μg/mL (1900 nM) for both doses. Intramuscular RPH-137 (30 and 80 mg/kg) had no effect on the infection process in Syrian hamsters. The comparison with the challenge control group showed that intraperitoneal RPH-137 (100 mg/kg) had statistically significant effects on a number of parameters, including a 27% reduction in inflammation and a 30% reduction in the total lesion area of the lungs by Day 7. Intragastric molnupiravir (300 mg/kg twice daily) significantly inhibited SARS-CoV-2 infection.Conclusions: both RPH-137 and molnupiravir inhibited the cytopathic effect of SARS-CoV-2 in Vero cells. In Syrian hamsters, molnupiravir demonstrated a more pronounced inhibition of SARS-CoV-2 infection than RPH-137. However, RPH-137 had statistically significant effects on a range of parameters. This offers additional perspectives for further research.

Novel chlorine-extending polymer coating with prolonged antiviral activity against SARS-CoV-2.

We previously reported a novel polymeric surface coating, namely, HaloFilm™ that can immobilize and extend the antimicrobial activity of chlorine on surfaces. In this study, we demonstrated the continuous antiviral efficacy of HaloFilm when applied on stainless steel and cotton gauze as two representative models for non-porous and porous surfaces against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Forty-eight hours post HaloFilm application and chlorination and 2 h post the viral challenge, the inoculum titre was reduced by 2.25 ± 0.33 and ≥4.36 ± 0.23 log10 TCID50 on non-porous and porous surfaces, respectively. The half-life of the virus was shorter (13.86 min) on a HaloFilm-coated surface than what has been reported on copper (46.44 min).

Egyptian cobra (Naja haje haje) venom phospholipase A2: a promising antiviral agent with potent virucidal activity against simian rotavirus and bovine coronavirus

Viral infections are linked to a variety of human diseases. Despite the achievements made in drug and vaccine development, several viruses still lack preventive vaccines and efficient antiviral compounds. Thus, developing novel antiviral agents is of great concern, particularly the natural products that are promising candidates for such discoveries. In this study, we have purified an approximately 15 kDa basic phospholipase A2 (PLA2) enzyme from the Egyptian cobra Naja haje haje venom. The purified N. haje PLA2 showed a specific activity of 22 units/mg protein against 6 units/mg protein for the whole crude venom with 3.67-fold purification. The antiviral activity of purified N. haje PLA2 has been investigated in vitro against bovine coronavirus (BCoV) and simian rotavirus (RV SA-11). Our results showed that the CC50 of PLA2 were 33.6 and 29 µg/ml against MDBK and MA104 cell lines, respectively. Antiviral analysis of N. haje PLA2 showed an inhibition of BCoV and RV SA-11 infections with a therapeutic index equal to 33.6 and 16, respectively. Moreover, N. haje PLA2 decreased the BCoV and RV SA-11 titers by 4.25 log10 TCID50 and 2.5 log10 TCID50, respectively. Thus, this research suggests the potential antiviral activity of purified N. haje PLA2 against BCoV and RV SA-11 infections in vitro.

PseudoRHDV constructed with feline calicivirus genome as vector has the characteristics of well proliferation in vitro

Rabbit hemorrhagic disease virus (RHDV) is a major member of the Caliciviridae. which is fatal to wild and domestic European rabbit. Because RHDV does not reproduce stably in vitro, molecular studies on this pathogen have been limited. Feline calicivirus (FCV), also a member of the Caliciviridae, reproduces well in vitro and is a good viral vector. As these viruses share similar genomic structures, we hypothesized that a chimeric infectious clone could be constructed by replacing the corresponding regions of the FCV genome with the structural proteins VP60 and VP10 and the 3′ non-translated region of the RHDV genome. Transfection of the infectious clone into RK13 cells made it possible to rescue the chimeric virus, named pseudoRHDV, which reproduced in an RK13 cell line with high titer. An infectious pseudoRHDV was produced, which proliferated in RK13 cells to at least 15 generations. PseudoRHDV caused significant cytopathic changes in the RK13 cells, with a viral titer was 9.74 log10 TCID50 / mL. The pseudoRHDV constructed in this study will be helpful for investigating the molecular biology of RHDV, especially its interaction with the host. The model can also be used to explore some common laws between FCV and RHDV.

Estimated quantity of swine virus genomes based on quantitative PCR analysis in spray-dried porcine plasma samples collected from multiple manufacturing plants.

This survey was conducted to estimate the incidence and level of potential viral contamination in commercially collected porcine plasma. Samples of spray dried porcine plasma (SDPP) were collected over a 12- month period from eight spray drying facilities in Spain, England, Northern Ireland, Brazil, Canada, and the United States. In this survey, viral load for several porcine pathogens including SVA, TGEV, PRRSV (EU and US strains), PEDV, PCV-2, SIV, SDCoV and PPV were determined by qPCR. Regression of Ct on TCID50 of serial diluted stock solution of each virus allowed the estimate of potential viral level in SDPP and unprocessed liquid plasma (using typical solids content of commercially collected porcine plasma). In this survey SVA, TGEV or SDCoV were not detected in any of the SDPP samples. Brazil SDPP samples were free of PRRSV and PEDV. Samples of SDPP from North America primarily contained the PRRSV-US strain while the European samples contained the PRRSV-EU strain (except for one sample from each region containing a relatively low estimated level of the alternative PRRSV strain). Estimated viral level tended to be in the range from <1.0 log10 TCID50 to <2.5 log10 TCID50. Estimated level of SIV was the exception with a very low incidence rate but higher estimated viral load <3.9 log10 TCID50. In summary, the incidence of potential viral contamination in commercially collected porcine plasma was variable and estimated virus level in samples containing viral DNA/RNA was relatively low compared with that occurring at the peak viremia during an infection for all viruses or when considering the minimal infectious dose for each of them.

Survival of SARS-CoV-2 in artificial seawater and on the surface of inanimate materials.

There is a potential risk for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) spread through human contact with seafood and the inanimate materials contaminated by the virus. In this study, we examined the stability of the virus in artificial seawater (ASW) and on the surface of selected materials. SARS‐CoV‐2 (3.75 log10 TCID50) in ASW at 22℃ maintained infectious about 3 days and at 4℃ the virus survived more than 7 days. It should be noticed that viable virus at high titer (5.50 log10 TCID50) may survive more than 20 days in ASW at 4℃ and for 7 days at 22℃. SARS‐CoV‐2 on stainless steel and plastic bag maintained infectious for 3 days, and on nonwoven fabric for 1 day at 22℃. In addition, the virus remained infectious for 9 days on stainless steel and non‐woven fabric, and on plastic bag for 12 days at 4℃. It is important to highlight the role of inanimate material surfaces as a source of infection and the necessity for surface decontamination and disinfection.

Determining the Stability of Human Betacoronavirus OC43 on Different Surfaces

Scientists continue to study SARS‐CoV‐2, the virus currently responsible for a worldwide pandemic, to determine the best methods to inactivate the virus on surfaces and reduce the risk of contact transmission. Its classification as a Biosafety Level (BSL) ‐3 pathogen complicates research since few facilities have the capacity for this level of containment. Human betacoronavirus OC43 (OC43) is a good surrogate for SARS‐CoV‐2 based on its genetic similarity and OC43’s BSL‐2 classification. Two industry specific surfaces were inoculated with OC43 and sampled at timepoints that reflect typical industry timelines for sanitation. The objective was to determine the stability of OC43 on typical meat facility surfaces.OC43 was propagated on human ileocecal colorectal adenocarcinoma cells (HRT‐18, ATCC CCL‐244). Infectious virus was quantified by indirect immunofluorescence TCID50 assays on HRT‐18 cells. Stainless steel grade 316 and polyethylene (poly top) coupons were inoculated with 100 ul of 2.51 x 106 TCID50/ml virus by pipette in a grid pattern at room temperature (20ºC) in an active biosafety cabinet in triplicate for each timepoint. Coupons were rinsed with 5 ml of sterile filtered beef extract buffer (BEB7), composed of Tris base, glycine, magnesium chloride, and beef extract pH adjusted to 7.0, at 0, 1, 4, 8, and 16 hours post inoculation (hpi). The collected rinsate was aliquoted and stored at ‐80ºC until the TCID50 assays were conducted in batch. The 16 hpi stainless steel samples were created at the time of the poly top experiment. The TCID50 assays were run in duplicate for each sample and TCID50/ml was calculated and averaged for each replicate. Percent recovery of infectious virus was determined for each timepoint.Virus was observed to have partially dried at 1 hpi and was completely dry at all following timepoints on both surfaces. Few infectious virions were lost between inoculation and 0 hpi collection from both surfaces. Mean percent recovery (MPR) of infectious OC43 from stainless steel and poly top at 0 hpi was 153% and 90%, respectively. At 1 hpi, the MPR from stainless steel was 65% while poly top was 123%. The variability of the assay explains these findings. Stainless steel and poly top had average recoveries of 60% and 25% at 4 hours, respectively. The lowest MPR for stainless steel was 17% at 8 hpi while the lowest MPR for poly top was 7% at 16 hpi. A higher MPR of 43% from stainless steel at 16 hpi reflects this timepoint being conducted on a different day.Infectious OC43 is still detectable on common meat facility surfaces several hours after inoculation, but our current knowledge of enveloped viruses asserts that they are inviable after drying. A maximum decrease of only 1 log TCID50 between inoculation and the 16 hpi samples means that a person could potentially be infected between cleanings if it is possible to transfer dried infectious virus from a surface to a mucous membrane. However, this is a conjecture that requires further study since the infectious dose of SARS‐CoV‐2 is unknown and no experiment to determine if this contact transfer is possible has been conducted. Currently, similar experiments with SARS are underway.

Preclinical Safety Evaluation: Acute and Repeated-Dose Toxicity of a New Intranasal Recombinant Vector Vaccine TB/FLU-04L Against Tuberculosis.

Vaccination against tuberculosis is one of the most successful medical measures to reduce morbidity and mortality. The BCG vaccine has been in use for more than 100 years, but its efficacy is still controversial. New vaccine candidates may offer better protection than available BCG vaccine. In this work, we studied the acute and the repeated-dose toxicity study of a new vector vaccine TB/Flu-04L against tuberculosis. The study was conducted on 60 BALB/c mice and 150 Wistar rats. The vaccine was administered intranasally and intravenously for the acute toxicity study. For the repeated-dose toxicity study, rats were intranasally immunized by 6.5 log10 TCID50 or 7.5 log10 TCID50 three times with 21-day intervals. Mortality, temperature, body weight, food and water consumption, hematological and biochemical parameters, urine analysis, as well as cardiovascular, respiratory, and central nervous system parameters were evaluated. A macroscopic examination of internal organs was performed. The TB/FLU-04L vaccine did not cause death among the mice and rats in the acute toxicity study. There were no pathological abnormalities in animal condition, behavior, food and water consumption, temperature, and body weight during the observation period. The results suggest that intranasal repeated-dose administration of the TB/FLU-04L vaccine does not exhibit significant toxicity in rats.Hematological and biochemistry analysis and the histological examination identified no toxicity-associated changes. The toxicity study in mice and rats showed that the intranasal vector vaccine TB/FLU-04L had no toxic effect. The tests confirm no adverse effects for laboratory animals in the studied parameters.

Bovine rhinitis B virus is highly prevalent in acute bovine respiratory disease and causes upper respiratory tract infection in calves.

Bovine respiratory disease (BRD) is the most significant cause of cattle morbidity and mortality worldwide. This multifactorial disease has a complex aetiology. Dogma posits a primary viral infection followed by secondary bacterial pneumonia. Bovine rhinitis B virus (BRBV) is an established aetiological agent of BRD, but little is known regarding its pathogenesis. Here, a BRD PCR panel identified 18/153 (11.8 %) lung samples and 20/49 (40.8 %) nasal swabs collected from cattle with respiratory signs as positive for BRBV, which was the most prevalent virus in nasal swabs. Primary bovine tracheal epithelial cells were used to isolate BRBV that was phylogenetically related to contemporary sequences from the USA and Mexico and genetically divergent from the previous sole BRBV isolate. To investigate virus pathogenesis, 1-week-old colostrum-deprived dairy calves were inoculated intranasally with 7.0 log10 TCID50 BRBV. Virus was isolated from nasal swabs, nasal turbinates, trachea and the brain of the challenged animals. Neutralizing antibodies were detected beginning 7 days post-inoculation and peaked at day 14. In situ hybridization (ISH) localized BRBV infection in the upper respiratory ciliated epithelial and goblet cells, occasionally associated with small defects of the superficial cilia lining. Sporadically, pinpoint ISH signals were also detected in cells resembling glial cells in the cerebrum in one calf. Together, these results demonstrate the BRBV infection is highly prevalent in acute BRD samples and while the pathogenicity of BRBV is minimal with infection largely limited to the upper respiratory tract, further research is needed to elucidate a possible initiatory role in BRD.

Rapid thermal inactivation of aerosolized SARS-CoV-2

Airborne transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is one of the leading mechanisms of spread, especially in confined environments. The study aims to assess the thermal inactivation of SARS-CoV-2 at high temperatures in the time scale of seconds. An electric heater with a coiled resistance wire is located perpendicularly to the airflow direction inside an air tunnel. The airflow rate through the tunnel was 0.6 m3/h (10 L/ min). SARS-CoV-2 were suspended in Dulbecco’s modified Eagle’s medium (DMEM) with 10 % fetal bovine serum (FBS), aerosolized by a nebulizer at a rate of 0.2 L/min and introduced to the airflow inside the heater with the use of a compressor and an aspirator. In the control experiment, with the heater off, SARS-CoV-2 passed through the system. In the virus inactivation test experiments, the heater’s outlet air temperature was set to 150 ± 5 °C and 220 ± 5 °C, and the air traveling through the tunnel was exposed to heat for 1.44 s. An inline gelatine filter harvested SARS-CoV-2 that passed through the system. The viral titer obtained from the gelatine filter in the control experiment was about 5.5 log10 TCID50. The virus's loss in viability in test experiments at 150 °C and 220 °C were 99.900 % and 99.999 %, respectively. The results indicate that high-temperature thermal inactivation substantially reduces the concentration of SARS-CoV-2 in the air within seconds.

Antimicrobial activities of three seaweeds extract against some human viral and bacterial pathogens

Microbial infections cause complicated health influences along with bad economic impacts. In the present investigation, three dominant seaweeds namely, Amphiroa anceps, Corallina officinalis and Sargassum filipendula were collected from different Egyptian sites at the Red Sea and Mediterranean Sea during autumn 2019. Organic extracts of the three algae were screened for their antibacterial activity against three pathogenic bacteria Salmonella typhiimurium, Staphylococcus aureus and Escherichia coli, in addition to in vitro antiviral activity against Rotavirus (RV), and Coxsackie virus B3 (CVB3) that cause severe diseases in human. Organic extract of A. anceps, C. officinalis and S. filipendula inhibit E. coli cells by 57.1%, 85.7%, and 91.4%, respectively. The highest level of concentration of the C. officinalis extract (100 µg/mL) inhibits 100% of Staphylococcus aureus cells followed by S. filipendula and A. anceps extract which inhibit 82.5% and 75% of S. aureus. Similarly, the highest concentration of C. officinalis extract inhibits S. typhiimurium by 80%. The extract of A. anceps exhibited a high antiviral effect against RV infection with TI = 22 and virus titers lessened by 2.75 log TCID50 followed by extractions of C. officinalis with TI = 18.3 and virus titers reduced by 2.5 log TCID50. Against CVB3 infection, the extract of A. anceps causes the highest antiviral activity with TI = 15 and reduce the viral titers by 2.5 log TCID50, followed by extractions of C. officinalis with TI = 8.8 and inhibition of virus titers by 1.75 log TCID50. Extract of S. filipendula displayed the lowest antiviral effects against RV and CVB3 infection with TI = 2.4 and 1.4, respectively. The obtained results clarified that the extract of three marine seaweeds maintains a potent antimicrobial activity, making them a future promising source of new antimicrobial drugs.

Sodium hypochlorite disinfection of SARS-CoV-2 spiked in water and municipal wastewater

Infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has the potential to be collected in wastewater from mucus, sputum, and feces of infected individuals, raising questions about the appropriate handling and treatment of the resulting wastewater. Current evidence indicates the likelihood of waterborne SARS-CoV-2 transmission is low; nonetheless, confirming the efficacy of disinfection against SARS-CoV-2 is prudent to ensure multiple barriers of protection for infectious SARS-CoV-2 that could be present in municipal and hospital wastewater. Sodium hypochlorite (free chlorine) is widely used for pathogen control in water disinfection applications. In the current study, we investigated the inactivation of SARS-CoV-2 in DI water and municipal wastewater primary influent by sodium hypochlorite (free chlorine) addition. Our results showed rapid disinfection of SARS-CoV-2, with less than 1 mg-min/L required for >3 log10 TCID50 reduction in DI water. More than 5 mg-min/L was required for 3 log10 TCID50 reduction in primary influent, suggesting potential shielding of the virus by suspended solids. These results are consistent with expected virus inactivation by free chlorine and suggest the adequacy of free chlorine disinfection for inactivation of infectious SARS-CoV-2 in water matrices.

Frequent lower respiratory tract disease in hematological patients with parainfluenza virus type 3 infection.

Human parainfluenza virus type 3 (HPIV-3) may cause lower respiratory tract infection disease (LRTI-D) after hematopoietic stem cell transplantation (HSCT). Most previous have studies focused on recipients of HSCT whereas data on characteristics and outcomes in patients with hematological malignancies (HMs) compared to non-hematological patients are limited. The prognostic value of viral load in respiratory specimens remains elusive. In a 2-year retrospective study, we determined the frequencies of LRTI-D in HM, HSCT, and in non-hematological patients, and HPIV-3 levels in respiratory tract secretions. Among 98 patients with HPIV-3 infection, including 31 HSCT and 40 HM, 36 had a diagnosis of LRTI-D. LRTI-D was significantly more frequent in patients with HM or HSCT (n = 32, 45.1%) than in non-hematological patients (n = 4, 14.8%) (p = 0.006). The median HPIV-3 loads were high in upper respiratory tract secretions regardless of the presence or absence of LRTI-D (8.3 log10 vs. 7.6 log10 TCID50 /106 cells). HPIV-3 loads in respiratory tract samples in HM were not significantly higher than those found in HSCT but significantly higher than in non-hematological patients (p = 0.007). In conclusion, LRTI-D was frequent in HM patients who were diagnosed with HPIV-3 infection.

Chemical compositions and experimental and computational modeling activity of sea cucumber Holothuria parva ethanolic extract against herpes simplex virus type 1

Sea cucumber has antiviral activities against various viruses including herpes simplex virus type 1 (HSV-1). The purpose of the current study was to determine the chemical profile and inhibitory effects of tegument ethanolic extract of Holothuria parva on HSV-1 infection and to elucidate the mechanism of antiviral action of this marine invertebrate. Cytotoxic activity of the extract on Vero cell line was determined using the methyl thiazolyl tetrazolium (MTT) method. The different components in H. parva were determined by GC-MS analysis. To assess the antiviral activity of the extract, MTT and 50% tissue culture infective dose (TCID50) were applied. Finally, computational molecular docking was performed to screen the potential binding ability of extract contents with HSV-1 surface glycoproteins and host cell surface receptors. Using MTT assay, the non-cytotoxic concentration of the extract was measured 46.5 μg/mL. Octadecanoic acid 2-hydroxy-1-(hydroxymethyl) ethyl ester and 2′,6′-acetoxylidide were two major constituents in the H. parva extract. Pre-treatment of HSV-1 with the ethanolic extract of H. parva led to a 2.1 log10 TCID50 reduction in virus titers when compared to the control group (P = 0.002). The log10 TCID50 reductions relative to the control group for co-penetration and post-penetration assays were 1.5 (P = 0.009) and 0.7 (P = 0.09), respectively. The tegument ethanolic extract of H. parva has significant antiviral properties against HSV-1. Docking analysis demonstrated that compounds of the extract [lidocaine and 2-hydroxy-1-(hydroxymethyl) ethyl ester octadecanoic acid] may cover similarly both virus and host cells binding domains leading to interference in virus attachment to cell receptors.

Retraction Note to: Methylene blue photochemical treatment as a reliable SARS-CoV-2 plasma virus inactivation method for blood safety and convalescent plasma therapy for COVID-19

In 2020, a new coronavirus, SARS-CoV-2, quickly spread worldwide within a few months. Although coronaviruses typically infect the upper or lower respiratory tract, the virus RNA can be detected in plasma. The risk of transmitting coronavirus via transfusion of blood products remains. As more asymptomatic infections are identified in COVID-19 cases, blood safety has become particularly important. Methylene blue (MB) photochemical technology has been proven to inactivate lipid-enveloped viruses with high efficiency and safety. The present study aimed to investigate the SARS-CoV-2 inactivation effects of MB in plasma. The SARS-CoV-2 virus strain was isolated from Zhejiang University. The live virus was harvested from cultured VERO-E6 cells, and mixed with MB in plasma. The MB final concentrations were 0, 1, 2, and 4 μM. The “BX-1 AIDS treatment instrument” was used at room temperature, the illumination adjusted to 55,000 ± 0.5 million Lux, and the plasma was irradiated for 0, 2, 5, 10, 20, and 40 mins using light at a single wavelength of 630 nm. Virus load changes were measured using quantitative reverse transcription- PCR. BX-1 could effectively eliminate SARS-CoV-2 within 2 mins in plasma, and the virus titer declined to 4.5 log10 TCID50 (median tissue culture infectious dose)/mL. BX-1 is based on MB photochemical technology, which was designed to inactivate HIV-1 virus in plasma. It was proven to be safe and reliable in clinical trials of HIV treatment. In this study, we showed that BX-1 could also be applied to inactivate SARS-CoV-2. During the current outbreak, this technique it has great potential for ensuring the safety of blood transfusions, for plasma transfusion therapy in recovering patients, and for preparing inactivated vaccines.

SARS-CoV-2 Production in a Scalable High Cell Density Bioreactor.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has demonstrated the value of pursuing different vaccine strategies. Vaccines based on whole viruses, a widely used vaccine technology, depend on efficient virus production. This study aimed to establish SARS-CoV-2 production in the scalable packed-bed CelCradleTM 500-AP bioreactor. CelCradleTM 500-AP bottles with 0.5 L working volume and 5.5 g BioNOC™ II carriers were seeded with 1.5 × 108 Vero (WHO) cells, approved for vaccine production, in animal component-free medium and infected at a multiplicity of infection of 0.006 at a total cell number of 2.2–2.5 × 109 cells/bottle seven days post cell seeding. Among several tested conditions, two harvests per day and a virus production temperature of 33 °C resulted in the highest virus yield with a peak SARS-CoV-2 infectivity titer of 7.3 log10 50% tissue culture infectious dose (TCID50)/mL at 72 h post-infection. Six harvests had titers of ≥6.5 log10 TCID50/mL, and a total of 10.5 log10 TCID50 were produced in ~5 L. While trypsin was reported to enhance virus spread in cell culture, addition of 0.5% recombinant trypsin after infection did not improve virus yields. Overall, we demonstrated successful animal component-free production of SARS-CoV-2 in well-characterized Vero (WHO) cells in a scalable packed-bed bioreactor.

Detection of African swine fever virus in feed dust collected from experimentally inoculated complete feed using quantitative PCR and virus titration assays.

African swine fever virus (ASFV) is a current threat to global pork production due to its high case fatality rate, lack of efficacious vaccine and recent transboundary spread into new regions of the world. Preventing introduction and further spread of ASFV is critical for countries currently negative for the virus. ASFV is stable in feed ingredients subjected to transoceanic conditions and transmission occurs through the natural consumption of contaminated feed. In this study, we investigated the use of feed dust collected from experimentally inoculated feed as a novel diagnostic sample type for ASFV detection. Moist swabs were used to collect dust from creep feeders after natural consumption of feed inoculated with 3.1-5.4 log10 TCID50 /g ASFV Georgia 2007 in the presence and absence of antimicrobial feed additives. Results validate the potential use of feed dust swabs as a novel diagnostic surveillance tool for detection and quantification of viral nucleic acid and infectious virus titre in ASFV-contaminated feed.

Decontamination of SARS-CoV-2 contaminated N95 filtering facepiece respirators using artificial sun lamps.

AimsAssess the feasibility of using light from artificial sun lamps to decontaminate N95 filtering facepiece respirators (FFRs) contaminated with SARS‐CoV‐2.Methods and ResultsFFR coupons or whole FFRs contaminated with 5 log10 TCID50 (target concentration) SARS‐CoV‐2 in culture media, simulated saliva, or simulated lung fluid were dried for 1–2 h, then exposed to light from tanning and horticulture lamps to assess decontamination. Exposed coupons and whole FFRs showed SARS‐CoV‐2 inactivation for all matrices tested. Furthermore, FFRs still met performance specifications after five decontamination cycles.ConclusionsIt is feasible that artificial sunlight from these sun lamps can be used to decontaminate FFRs provided the UV dose is sufficient and the light is unobstructed. Furthermore, decontamination can be performed up to five times without degrading FFR performance.Significance and Impact of the StudyThis research shows a proof of principle that artificial sun lamps may be an option to decontaminate SARS‐CoV‐2 on N95 FFRs. UV doses required for inactivation to levels below detection ranged from 4 to 37·8 J cm−2 depending on the light source, virus matrix and FFR type.

Inhibition of herpes simplex virus type 1 infection by Sambucus ebulus extract in vitro.

Background: The emergence of drug-resistant strains of herpes simplex virus type 1 (HSV-1) has been increasingly reported. Therefore, attempts to discover new antiviral agents in particular from natural compounds are required. In this study, we evaluated the possible inhibitory effects of hydroalcoholic extract of Sambucus ebulus (S. ebulus ) against HSV-1. Methods: S. ebulus extract was produced by maceration method. MTT assay was used to evaluate the cytotoxicity effects of the S. ebulus extract; also, antiviral effects were measured both by test TCID50 and quantitative real-time PCR methods. To study the inhibitory impact of S. ebulus extract on the expression of HSV-1 antigens, indirect immunofluorescence assay (IFA) was also performed. All analyses were performed using the GraphPad Prism software v. 7.0. Results: In the postexposure assay of HSV-1 with S. ebulus extract at the highest nontoxic concentration (75 μg/mL), S. ebulus extract led to 2.6 log10 TCID50 reduction in infectious virus titer. At the highest nontoxic concentration, the S. ebulus extract led to inhibition rates of 91.2%, based on the quantitative real-time PCR assay results (p<0.001). Also, in the immunofluorescence assay, a significant reduction was observed in fluorescence emission intensity in HSV-1-infected cell treated with S. ebulus extract compared to the control group. Conclusion: S. ebulus extract is a novel and effective natural compound in reducing HSV-1 titer and future studies should be conducted to discover the complete mechanism of antiviral effect of this natural compound.