Artemisinin analogues as potent inhibitors of in vitro hepatitis C virus replication

We reported previously that Artemisinin (ART), a widely used anti-malarial drug, is an inhibitor of in vitro HCV subgenomic replicon replication. We here demonstrate that ART exerts its antiviral activity also in hepatoma cells infected with full length infectious HCV JFH-1. We identified a number of ART analogues that are up to 10-fold more potent and selective as in vitro inhibitors of HCV replication than ART. The iron donor Hemin only marginally potentiates the anti-HCV activity of ART in HCV-infected cultures. Carbon-centered radicals have been shown to be critical for the anti-malarial activity of ART. We demonstrate that carbon-centered radicals-trapping (the so-called TEMPO) compounds only marginally affect the anti-HCV activity of ART. This provides evidence that carbon-centered radicals are not the main effectors of the anti-HCV activity of the Artemisinin. ART and analogues may possibly exert their anti-HCV activity by the induction of reactive oxygen species (ROS). The combined anti-HCV activity of ART or its analogues with L-N-Acetylcysteine (L-NAC) [a molecule that inhibits ROS generation] was studied. L-NAC significantly reduced the in vitro anti-HCV activity of ART and derivatives. Taken together, the in vitro anti-HCV activity of ART and analogues can, at least in part, be explained by the induction of ROS; carbon-centered radicals may not be important in the anti-HCV effect of these molecules

Spatiotemporal analysis and forecasting of lumpy skin disease outbreaks in Ethiopia based on retrospective outbreak reports

IntroductionLumpy skin disease is a viral disease that affects cattle belonging to genus Capripoxvirus (Poxviridae) and lead to significant economic losses.ObjectiveThe objective of this study was to evaluate the distribution of lumpy skin disease (LSD) outbreaks and predict future patterns based on retrospective outbreak reports in Ethiopia.MethodsData were collected through direct communication with regional laboratories and a hierarchical reporting system from the Peasant Associations to Ministry of Agriculture. Time-series data for the LSD outbreaks were analyzed using classical additive time-series decomposition and STL decomposition. Four models (ARIMA, SARIMA, ETS, STLF) were also used to forecast the number of LSD outbreaks that occurred each month for the years (2021–2025) after the models’ accuracy test was performed. Additionally, the space–time permutation model (STP) were also used to study retrospective space–time cluster analysis of LSD outbreaks in Ethiopia.ResultsThis study examined the geographical and temporal distribution of LSD outbreaks in Ethiopia from 2008 to 2020, reporting a total of 3,256 LSD outbreaks, 14,754 LSD-positive cases, 7,758 deaths, and 289 slaughters. It also covered approximately 68% of Ethiopia’s districts, with Oromia reporting the highest LSD outbreaks. In the LSD’s temporal distribution, the highest peak was reported following the rainy season in September to December and its lowest peak in the dry months of April and May. Out of the four models tested for forecasting, the SARIMA (3, 0, 0) (2, 1, 0) [12] model performed well for the validation data, while the STLF+Random Walk had a robust prediction for the training data. Thus, the SARIMA and STLF+Random Walk models produced a more accurate forecast of LSD outbreaks between 2020 and 2025. From retrospective Space–Time Cluster Analysis of LSD, eight possible clusters were also identified, with five of them located in central part of Ethiopia.ConclusionThe study’s time series and ST-cluster analysis of LSD outbreak data provide valuable insights into the spatial and temporal dynamics of the disease in Ethiopia. These insights can aid in the development of effective strategies to control and prevent the spread of the disease and holds great potential for improving efforts to combat LSD in the country

DEB025 (Alisporivir) Inhibits Hepatitis C Virus Replication by Preventing a Cyclophilin A Induced Cis-Trans Isomerisation in Domain II of NS5A

DEB025/Debio 025 (Alisporivir) is a cyclophilin (Cyp)-binding molecule with potent anti-hepatitis C virus (HCV) activity both in vitro and in vivo. It is currently being evaluated in phase II clinical trials. DEB025 binds to CypA, a peptidyl-prolyl cis-trans isomerase which is a crucial cofactor for HCV replication. Here we report that it was very difficult to select resistant replicons (genotype 1b) to DEB025, requiring an average of 20 weeks (four independent experiments), compared to the typically <2 weeks with protease or polymerase inhibitors. This indicates a high genetic barrier to resistance for DEB025. Mutation D320E in NS5A was the only mutation consistently selected in the replicon genome. This mutation alone conferred a low-level (3.9-fold) resistance. Replacing the NS5A gene (but not the NS5B gene) from the wild type (WT) genome with the corresponding sequence from the DEB025res replicon resulted in transfer of resistance. Cross-resistance with cyclosporine A (CsA) was observed, whereas NS3 protease and NS5B polymerase inhibitors retained WT-activity against DEB025res replicons. Unlike WT, DEB025res replicon replicated efficiently in CypA knock down cells. However, DEB025 disrupted the interaction between CypA and NS5A regardless of whether the NS5A protein was derived from WT or DEB025res replicon. NMR titration experiments with peptides derived from the WT or the DEB025res domain II of NS5A corroborated this observation in a quantitative manner. Interestingly, comparative NMR studies on two 20-mer NS5A peptides that contain D320 or E320 revealed a shift in population between the major and minor conformers. These data suggest that D320E conferred low-level resistance to DEB025 probably by reducing the need for CypA-dependent isomerisation of NS5A. Prolonged DEB025 treatment and multiple genotypic changes may be necessary to generate significant resistance to DEB025, underlying the high barrier to resistance

Novel strategies for the treatment of infections with pesti- and hepaciviruses

status: publishe

Construction of Antibody Phage Libraries and Their Application in Veterinary Immunovirology

Antibody phage display (APD) technology has revolutionized the field of immunovirology with its application in viral disease diagnostics and antiviral therapy. This robust and versatile technology allows the expression of an antibody fused to a phage coat protein on the surface of a filamentous phage. The DNA sequence coding for the antibody is packaged within the phage, linking the phenotype to genotype. Antibody phage display inherits the ability to rapidly generate and modify or improve high-affinity monoclonal antibodies, rendering it indispensable in immunology. In the last two decades, phage-display-derived antibodies have been extensively used in human medicine as diagnostic and therapeutic modalities. Recently, they are also gaining significant ground in veterinary medicine. Even though these advancements are mainly biased towards economically important animals such as chicken, cattle, and pigs, they are laying the foundation of fulfilling the unmet needs of veterinary medicine as antibody-based biologics in viral diagnostics, therapeutics, and immunoprophylaxis. This review provides a brief overview of the construction of antibody phage libraries and their application in diagnosis, prevention, and control of infectious viral diseases in veterinary medicine in detail

Construction of Antibody Phage Libraries and Their Application in Veterinary Immunovirology

Antibody phage display (APD) technology has revolutionized the field of immunovirology with its application in viral disease diagnostics and antiviral therapy. This robust and versatile technology allows the expression of an antibody fused to a phage coat protein on the surface of a filamentous phage. The DNA sequence coding for the antibody is packaged within the phage, linking the phenotype to genotype. Antibody phage display inherits the ability to rapidly generate and modify or improve high-affinity monoclonal antibodies, rendering it indispensable in immunology. In the last two decades, phage-display-derived antibodies have been extensively used in human medicine as diagnostic and therapeutic modalities. Recently, they are also gaining significant ground in veterinary medicine. Even though these advancements are mainly biased towards economically important animals such as chicken, cattle, and pigs, they are laying the foundation of fulfilling the unmet needs of veterinary medicine as antibody-based biologics in viral diagnostics, therapeutics, and immunoprophylaxis. This review provides a brief overview of the construction of antibody phage libraries and their application in diagnosis, prevention, and control of infectious viral diseases in veterinary medicine in detail.status: publishe

Angiogenic activity of hepatitis B and C viruses

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. The limited treatment options and poor prognosis of HCC patients underscore the importance of developing new therapeutic strategies. Infection with HBV and HCV are the major risk factors for developing HCC. While the precise molecular mechanisms that link HBV and HCV infections to the development and progression of HCC are not entirely understood, increasing evidence indicates that stimulation of angiogenesis by these viruses may contribute to HCC malignancy. In this review, we summarize the progress in understanding the role of HBV and HCV infection in liver and HCC angiogenesis, the mechanisms applied by these viruses to deregulate the angiogenic balance and the potential therapeutic options that come with this understanding.status: publishe

The role of phosphatidylinositol 4-kinases and phosphatidylinositol 4-phosphate during viral replication

Phosphoinositides (PI) are phospholipids that mediate signaling cascades in the cell by binding to effector proteins. Reversible phosphorylation of the inositol ring at positions 3, 4 and 5 results in the synthesis of seven different phosphoinositides. Each phosphoinositide has a unique subcellular distribution with a predominant localization in subsets of membranes. These lipids play a major role in recruiting and regulating the function of proteins at membrane interfaces [1]. Several bacteria and viruses modulate and exploit the host PI metabolism to ensure efficient replication and survival. Here, we focus on the roles of cellular phosphatidylinositol 4-phosphate (PI4P) and phosphatidylinositol 4-kinases (PI4Ks) during the replication cycle of various viruses. It has been well documented that phosphatidylinositol 4-kinase IIIβ (PI4KIIIβ, EC 2.7.1.67) is indispensable for viral RNA replication of several picornaviruses. Two recruitment strategies were reported: (i) binding and modulation of GBF1/Arf1 to enhance recruitment of PI4KIIIβ and (ii) interaction with ACBD3 for recruitment of PI4KIIIβ. PI4KIII has also been demonstrated to be crucial for hepatitis C virus (HCV) replication. PI4KIII appears to be directly recruited and activated by HCV NS5A protein to the replication complexes. In contrast to picornaviruses, it is still debated whether the α or the β isoform is the most important. PI4KIII can be explored as a target for inhibition of viral replication. The challenge will be to develop highly selective inhibitors for PI4KIIIα and/or β and to avoid off-target toxicity.status: publishe

Ribavirin for the treatment of chronic hepatitis C virus infection: a review of the proposed mechanisms of action

Roughly 20 years after the discovery of the hepatitis C virus (HCV), and 10 years after the launch of the current standard of care (SOC) therapy, i.e. the combination of pegylated interferon-alpha and ribavirin, antiviral treatment of chronic hepatitis C is at the dawn of a new era. The current SOC will be combined with a direct acting antiviral (DAA), i.e. either the HCV NS3 protease inhibitor Telaprevir or Boceprevir. Combinations of DAAs may have the potential to completely cure chronic HCV infection. Clinical data suggest that ribavirin may remain at least for some time, an important component even in combinations of different DAAs. Ironically, and much in contrast to the DAAs, the precise mechanism(s) by which ribavirin exerts its anti-HCV activity in infected patients still waits to be unravelled. Here we review the current views on the mechanism of action of ribavirin against chronic infections with HCV. Concerted efforts of modern pharmacogenetics, novel insights into innate immunity and contributions from molecular virology will hopefully allow deciphering the precise mechanism(s) that are at the basis of the antiviral effect of this nucleoside analogue. Such insights may help design improved strategies to fight chronic infections with HCV.status: publishe

African Swine Fever: Prevalence, Farm Characteristics, Farmer&rsquo;s Insight and Attitude toward Reporting of African Swine Fever Cases in the Northwest, West, Littoral and Southwest Regions of Cameroon

The African swine fever virus (ASFV) has been circulating in and ravaging the swine industry in Cameroon for decades. Annual ASFV epidemics occur in Cameroon from April to August. With the absence of vaccines and antiviral drugs against this virus, biosecurity has been the only effective control tool available. When properly applied, biosecurity measures allow control of the spread of ASFV and the eventual eradication of this virus. Many outbreak investigations by PCR were effected in Cameroon, with ASFV prevalences ranging from 15.23% to 42.80%. Considering that pre-outbreak studies are not available for Cameroon, the present study aimed at assessing the status of the animals before an outbreak. A two-stage cluster sampling study was conducted from January to March 2020. In this study, the primary unit was the farm and the secondary unit was the individual animals. In all, 97 farms were visited and 277 samples were collected. Pre-outbreak ASFV prevalence, as assessed by PCR, was 9.75%. In parallel, data were collected using a survey of farm characteristics, awareness and attitude of the farmers toward ASF. The survey results showed that 34.1% of the farms were backyard cemented piggeries with the majority having less than 10 pigs (54.1%). The majority of farmers (90.6%) had heard of and knew about the disease caused by ASF. Though 69.4% of the farmers were uninformed on the clinical signs of ASF, 73.6% of them did treat sick pigs presenting similar clinical signs to ASF (with no risk of mortality) with antibiotics, while 79.4% did not treat but sold the pigs presenting clinical signs similar to ASF with an increased risk of mortality. Sixty-three percent of the farmers had reported a case of ASF in the past and believed that reporting was useful and had no negative consequences on other farmers or third parties. We established that poor implementation of biosecurity measures in addition to poor training are contributing factors to the enzootic nature of ASFV in Cameroon and, thus, the spread of ASFV. Hence, pig farmers in Cameroon must be properly trained in ASFV awareness and the impact thereof on pig production. Furthermore, training will also facilitate the successful implementation of biosecurity measures to contain ASFV outbreaks