Antiviral activity of brequinar against African swine fever virus infection in vitro

Research Areas: VirologyAfrican swine fever virus (ASFV) is a double-stranded DNA virus that causes an acute and hemorrhagic disease in domestic swine, resulting in significant economic losses to the global porcine industry. The lack of vaccines and antiviral drugs highlights the urgent need for antiviral studies against ASFV. Here, we report that brequinar (BQR), which is a specific inhibitor of dihydroorotate dehydrogenase, robustly inhibits ASFV replication in Vero cells, as well as in porcine macrophages. We demonstrate that BQR exerts its antiviral activity in a dosedependent manner through the depletion of pyrimidine pool. Although BQR does not affect the synthesis of an early viral protein, pI215L, the synthesis of late viral proteins, p17 and p72, is suppressed in the presence of BQR. We also show that BQR is able to induce cellular antiviral response in ASFV-infected macrophages by enhancing the expression of interferon-stimulated genes. Taken together, our study reveals that targeting nucleotide biosynthesis represents a promising strategy for developing antiviral agents against ASFV.info:eu-repo/semantics/publishedVersio

Pathology of porcine peripheral white blood cells during infection with African swine fever virus

<p>Abstract</p> <p>Background</p> <p>African swine fever virus (ASFV) is the causative agent of African swine fever (ASF) that is the significant disease of domestic pigs. Several studies showed that ASFV can influence on porcine blood cells in vitro. Thus, we asked ourselves whether ASFV infection results in changes in porcine blood cells in vivo. A series of experiments were performed in order to investigate the effects of ASFV infection on porcine peripheral white blood cells. Nine pigs were inoculated by intramuscular injection with 10⁴50% hemadsorbing doses of virus (genotype II) distributed in Armenia and Georgia. The total number of fifteen cell types was calculated during experimental infection.</p> <p>Results</p> <p>Although band-to-segmented neutrophils ratio became much higher (3.5) in infected pigs than in control group (0.3), marked neutropenia and lymphopenia were detected from 2 to 3 days post-infection. In addition to band neutrophils, the high number of other immature white blood cells, such as metamyelocytes, was observed during the course of infection. From the beginning of infection, atypical lymphocytes, with altered nuclear shape, arose and became 15% of total cells in the final phase of infection. Image scanning cytometry revealed hyperdiploid DNA content in atypical lymphocytes only from 5 days post-infection, indicating that DNA synthesis in pathological lymphocytes occurred in the later stages of infection.</p> <p>Conclusion</p> <p>From this study, it can be concluded that ASFV infection leads to serious changes in composition of white blood cells. Particularly, acute ASFV infection in vivo is accompanied with the emergence of immature cells and atypical lymphocytes in the host blood. The mechanisms underlying atypical cell formation remain to be elucidated.</p

A new microtubule-stabilizing agent shows potent antiviral effects against African swine fever virus with no cytotoxicity

© 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.African swine fever virus (ASFV) is the causal agent of a fatal disease of domestic swine for which no effective antiviral drugs are available. Recently, it has been shown that microtubule-targeting agents hamper the infection cycle of different viruses. In this study, we conducted in silico screening against the colchicine binding site (CBS) of tubulin and found three new compounds with anti-ASFV activity. The most promising antiviral compound (6b) reduced ASFV replication in a dose-dependent manner (IC50 = 19.5 μM) with no cellular (CC50 > 500 μM) and animal toxicity (up to 100 mg/kg). Results also revealed that compound 6b interfered with ASFV attachment, internalization and egress, with time-of-addition assays, showing that compound 6b has higher antiviral effects when added within 2-8 h post-infection. This compound significantly inhibited viral DNA replication and disrupted viral protein synthesis. Experiments with ASFV-infected porcine macrophages disclosed that antiviral effects of the compound 6b were similar to its effects in Vero cells. Tubulin polymerization assay and confocal microscopy demonstrated that compound 6b promoted tubulin polymerization, acting as a microtubule-stabilizing, rather than a destabilizing agent in cells. In conclusion, this work emphasizes the idea that microtubules can be targets for drug development against ASFV.This work of E. A., A. H., and H. Z. was supported by the RA MESCS Science Committee, Armenia [grant number 19YR-1F039]; the work of F. F. was supported by the FCT – Fundação para a Ciência e a Tecnologia, Portugal [grant number UIDB/00276/2020].info:eu-repo/semantics/publishedVersio

Whole-genome-based phylogeny of African swine fever virus

Aim: A genome-scale phylogenetic analysis was used to infer the evolutionary dynamics of Asfarviridae – African swine fever virus (ASFV) – and better define its genetic diversity. Materials and Methods: All complete ASFV genomes from NCBI's resource as of March 2020 were used. The phylogenetic analysis used maximum likelihood and neighbor-joining methods. The evolutionary models detection was done with the help of the package of programs MEGA-X. Algorithms were used to build phylogenetic trees for type B DNA polymerases of ASFV (n=34) and HcDNAV (n=2), as an external group. Results: An expedient categorization of the Asfarviridae family uses five clades. Genotype 1 (except for LIV 5/40 virus isolate) as well genotype 7 are assigned to the alpha clade; genotype 2 to the beta clade; genotypes 8, 9, and 10 to the gamma clade; genotype 5 to the delta clade; and genotypes 3, 4, and 20, as well as genotype 22 and the LIV 5/40 isolate to the epsilon clade. Branch lengths on the phylogenetic tree are proportional to genetic distance along the branch. Branches at the phylogenetic tree of Asfarviridae are much shorter than branches for Baculoviridae. Shorter branches in ASFVs population suggest that Asfarviridae evolved relatively recently and remain more closely related. Conclusion: We suggest applying more robust standards using whole genomes to ensure the correct classification of ASFV and maintain phylogeny as a useful tool

First molecular detection of the presence of honey bee viruses in insects, Varroa destructor mites, and pollinated plants in an isolated region of Armenia

Background and Aim: Recently, viral diseases of honey bees (Apis mellifera) have presented an increasing threat to beekeeping. This study aimed to examine the presence of honey bee viruses in Apis and non-Apis bee species, the mite Varroa destructor, and pollinated plants in Armenia. Materials and Methods: Sampling was performed in Tavush Province, in the northeast of the Republic of Armenia, from August to November 2019. Overall, 200 A. mellifera bees, 50 V. destructor mites, and 20 wasps were collected (corresponding to three bees, five mites, and 2–11 wasps in each investigated sample) and homogenized for RNA isolation and detection of viruses. Ten pollinated plants were taken from each plant, and 2 g of each sample was used for homogenization. In each investigated case Apis mellifera, Varroa destructor, Vespula germanica and plants received percentages of the virus presence. Results: Six important honey bee viruses (acute bee paralysis virus [ABPV], deformed wing virus [DWV], A. mellifera norovirus [ANV], Lake Sinai virus-2 [LSV-2], Big Sioux River virus [BSRV], and A. mellifera filamentous virus [AmFV]) were detected in samples by polymerase chain reaction. Our results showed that DWV, ANV, and ABPV were the most common viruses in honey bees. All viruses were detected in wasps, but LSV-2 and ANV were present in almost all samples. Conclusion: Our results showed that almost all viruses were present in V. destructor. Although ANV is very common in honey bees, it did not appear in any mite samples. Our study indicates that viruses typically associated with honey bees were also actively infecting wasps. Our data suggest that the survival of viruses in plants can be an important source of seasonal transmission of viruses to bees. In addition, pollinated plants can potentially serve as reservoirs for honey bee viruses

Evidence of hemolysis in pigs infected with highly virulent African swine fever virus

Aim: The research was conducted to understand more profoundly the pathogenetic aspects of the acute form of the African swine fever (ASF). Materials and Methods: A total of 10 pigs were inoculated with ASF virus (ASFV) (genotype II) in the study of the red blood cells (RBCs), blood and urine biochemistry in the dynamics of disease. Results: The major hematological differences observed in ASFV infected pigs were that the mean corpuscular volume, mean corpuscular hemoglobin, and hematocrits were significantly decreased compared to controls, and the levels of erythropoietin were significantly increased. Also were detected the trends of decrease in RBC count at terminal stages of ASF. Analysis of blood biochemistry revealed that during ASF development, besides bilirubinemia significantly elevated levels of lactate dehydrogenase, and aspartate aminotransferase were detected. Analysis of urine biochemistry revealed the presence of bilirubinuria, proteinuria during ASF development. Proteinuria, especially at late stages of the disease reflects a severe kidney damage possible glomerulonefritis. Conclusion: The results of this study indicate the characteristics of developing hemolytic anemia observed in acute ASF (genotype II)

The Effect of Low-Energy Laser-Driven Ultrashort Pulsed Electron Beam Irradiation on Erythropoiesis and Oxidative Stress in Rats

Anemia is a commonly observed consequence of whole-body exposure to a dose of X-ray or gamma irradiation of the order of the mean lethal dose in mammals, and it is an important factor for the determination of the survival of animals. The aim of this study was to unravel the effect of laser-driven ultrashort pulsed electron beam (UPEB) irradiation on the process of erythropoiesis and the redox state in the organism. Wistar rats were exposed to laser-driven UPEB irradiation, after which the level of oxidative stress and the activities of different antioxidant enzymes, as well as blood smears, bone marrow imprints and sections, erythroblastic islets, hemoglobin and hematocrit, hepatic iron, DNA, and erythropoietin levels, were assessed on the 1st, 3rd, 7th, 14th, and 28th days after irradiation. Despite the fact that laser-driven UPEB irradiation requires quite low doses and repetition rates to achieve the LD50 in rats, our findings suggest that whole-body exposure with this new type of irradiation causes relatively mild anemia in rats, with subsequent fast recovery up to the 28th day. Moreover, this novel type of irradiation causes highly intense processes of oxidative stress, which, despite being relatively extinguished, did not reach the physiologically stable level even at the 28th day after irradiation due to the violations in the antioxidant system of the organism

Pathomorphology of the brain in the acute form of African swine fever

The brains of 10 infected pigs were examined for histopathology and presence of African swine fever virus (ASFV) DNA ASFV infection induces inflamed meninges, cerebral edema and vascular thrombosis, as well as subdural hematomas. Slight tension in the dura mater, flattening of the gyri and narrowing of the sulci were also observed at four days post infection (dpi). Enlarged perivascular spaces were detected for most vessels of the brain after three to four dpi. Considerable lymphocytic infiltration of the brain tissue was observed at the terminal stage of disease. ASFV was present in all investigated areas of brain beginning from three to four dpi. The isolated virus do not differ from the used in present study Georgia 2007 strain

Severe Acute Respiratory Syndrome Coronavirus-2 Delta Variant Study In Vitro and Vivo

At the end of 2019, an outbreak of a new severe acute respiratory syndrome caused by a coronavirus occurred in Wuhan, China, after which the virus spread around the world. Here, we have described the adaptive capacity and pathogenesis of the SARS-CoV-2 Delta variant, which is widespread in Armenia, in vitro and vivo on Syrian hamsters. We have studied the changes in the SARS-CoV-2genome using viral RNA sequencing during virus adaptation in vitro and in vivo. Our findings revealed that SARS-CoV-2 in Syrian hamsters causes a short-term pulmonary form of the disease, the first symptoms appear within 48 h after infection, reach 5–7 days after infection, and begin to disappear by 7–9 days after infection. The virus induces pathogenesis in the blood and bone marrow, which generally corresponds to the manifestation of the inflammatory process. The pulmonary form of the disease passes faster than changes in blood cells and bone marrow. Our data show that hamster organs do not undergo significant pathological changes in the Delta variant of SARS-CoV-2 infection