abstract: ABSTRACT In terms of prevalence, human suffering and costs dengue infections are the most important arthropod-borne viral disease worldwide. Dengue virus (DENV) is a mosquito-borne flavivirus and the etiological agent of dengue fever and dengue hemorrhagic fever. Thus, development of a safe and efficient vaccine constitutes an urgent necessity. Besides the traditional strategies aim at generating immunization options, the usage of viral vectors to deliver antigenic stimulus in order to elicit protection are particularly attractive for the endeavor of a dengue vaccine. The viral vector (MVvac2) is genetically equivalent to the currently used measles vaccine strain Moraten, which adds practicality to my approach. The goal of the present study was to generate a recombinant measles virus expressing structural antigens from two strains of DENV (DENV2 and DENV4) The recombinant vectors replication profile was comparable to that of the parental strain and expresses either membrane bound or soluble forms of DENV2 and DENV4 E glycoproteins. I discuss future experiments in order to demonstrate its immunogenicity in our measles-susceptible mouse model. / Dissertation/Thesis / M.S. Biology 2013

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-12-06T12:15:32Z No. of bitstreams: 1 Deborah de Farias Guimaraes.pdf: 1687954 bytes, checksum: e5f2a9cf898f17aa2213bda98fc5c502 (MD5) / Made available in DSpace on 2017-12-06T12:15:32Z (GMT). No. of bitstreams: 1 Deborah de Farias Guimaraes.pdf: 1687954 bytes, checksum: e5f2a9cf898f17aa2213bda98fc5c502 (MD5) Previous issue date: 2017-07-13 / The flavivirus genus (family Flaviviridae) comprises some of the most relevant arboviruses for public health, that can cause disease in humans and animals. Some members of this Family such West Nile virus (WNV) and Saint Louis Encephalitis virus (SLEV) are antigenically related. They develop similar symptoms and their serological diagnosis may show cross reaction with other Flavivirus, present in the same geographical area. In this context, the establishment of a platform for differential serological diagnosis in these arboviruses, is crucial. Among other methodologies, the Enzyme-linked immunosorbent assay (ELISA) is the most used technique for flavivirus diagnosis, with subsequent confirmation by plaque reduction neutralization test (PRNT). Thus, the present work aimed to develop a differential immunoassay diagnostic platform for WNV and SLEV, using their structural proteins as antigens, derived from viral chimeras YFV-17D-WNV-3M and YFV-17D-SLEV respectively, previously constructed in our research group (Department of Virology, Fiocruz / PE). We analyzed 155 samples of equine sera from the state of Pernambuco-Brazil, for WNV and SLEV by blocking ELISA technique, resulting in 149 and 132 positive samples among them, respectively. All samples were tested by PRNT75 for validating the results of ELISA confirming 31 positive samples for WNV and 20 for SLEV. These results demonstrated that the platform of large-scale serological screening developed in this work is effective and has the potential use for evaluation of sera, from different species of flavivirus in Brazil. / O gênero Flavivirus, família Flaviviridae, compreende algumas das arboviroses mais importantes para saúde pública, causadoras de doenças em humanos e animais. Alguns membros desta família, como por exemplo, o vírus do oeste do Nilo (West Nile virus, WNV) e vírus da encefalite São Luís (Saint Louis encephalitis virus, SLEV) estão relacionados antigenicamente, o que significa que além de desenvolverem sintomatologia bastante parecida, o seu diagnóstico sorológico pode apresentar reação cruzada com outros flavivírus presentes na mesma área geográfica. Dessa forma, percebe-se a urgência de uma plataforma de diagnóstico sorológico diferencial entre as arboviroses anteriormente citadas. Dentre as metodologias atuais, o ELISA é o mais utilizado em flavivírus, com posterior confirmação por teste sorológico ouro, o ensaio de neutralização por redução de placas (PRNT). Diante disso, o presente trabalho objetivou a construção de uma plataforma de diagnóstico imunoenzimático diferencial para WNV e SLEV, através do ELISA de bloqueio e realizar uma comparação com a metodologia do ELISA de captura utilizando as mesmas amostras. Com isso, analisou-se 155 amostras de soros de equinos do Estado de Pernambuco para o WNV e SLEV por ELISA de bloqueio, resultando em 149 e 132 amostras positivas, respectivamente. Todas as amostras foram testadas por PRNT75 para validação dos resultados do ELISA, identificando neste teste 31 amostras positivas para WNV e 21 para SLEV. Demonstrando que a plataforma de triagem sorológica em larga escala, desenvolvida neste trabalho, é eficiente para a avaliações epidemiológicas e monitoramento de flavivírus no território brasileiro.

Rondônia apresenta área com rica diversidade de artrópodes, porém pouco se conhece sobre a transmissão de arbovírus por estas espécies. O presente trabalho visou detectar arbovírus, por meio da RT-PCR e da Duplex RT-PCR, nas espécies de dipteros coletados no Estado, bem como caracterizá-los pela reação de sequenciamento. A RT-PCR e a Duplex RT-PCR detectaram as suspensões dos vírus Mayaro e Oropouche até 104 e 101 TCID50/mL, respectivamente, porém o vírus Dengue 2 em pools contendo menos de três mosquitos infectados foi negativa. O controle endógeno foi detectado em 66,8 % das amostras, sendo que, em pools contendo entre um e três mosquitos, a detecção foi aproximadamente metade da detecção nos pools contendo entre 11 e 15. Em 0,66 % dos pools foi encontrado o vírus Oropouche e em outros 0,66 %, o vírus Cacipacoré. O vírus Oropouche foi detectado em Coquillettidia sp. e Deinocerites sp., enquanto o vírus Cacipacoré foi encontrado em Anopheles sp. e Culex sp. As técnicas possibilitaram a detecção dos arbovírus pesquisados nos pools coletados em Rondônia. / The Rondônia state has an area with rich arthropods diversity although the knowledge about the arboviruses transmition for these species is poor. The present work aimed to detect arboviruses through RT-PRC and RT-PCR Duplex in the diptera species collected in the region as well as their characterization through the sequence reaction. The RT-PRC and RT-PCR Duplex detected the Mayaro and Oropouche virus suspensions until 104 e 101 TCID50/mL respectively, although it was negative for the Dengue 2 virus in pools containing less than three infected mosquitoes. The endogenous control was detected in 66,8 % of samples and from pools containing from one to three mosquitoes the detection rate was approximately half from that obtained from pools with 11 to 15 mosquitoes. Oropouche virus was found in 0,66 % of pools and Cacipacore virus also in 0,66 % of pools. Oropouche virus was detected in Coquillettidia sp. and Deinocerites sp. while Cacipacoré virus was found in Anopheles sp. and Culex sp. The techniques allowed the detection of examined arboviruses in the pools collected from Rondonia.

Flaviviruses are important emerging and re-emerging arthropod-borne pathogens that cause significant morbidity and mortality in humans. It consists of globally distributed human pathogens such as tick-borne encephalitis virus (TBEV), West Nile virus (WNV), Japanese encephalitis virus (JEV), yellow fever virus (YFV), dengue virus (DENV), and Zika virus (ZIKV). Depending on type, flaviviruses can cause a variety of symptoms ranging from haemorrhage to neurological disorders. Virus infection is detected by host pattern recognition receptors (PRRs), and through downstream signalling it leads to the production of interferons (IFNs). These IFNs then act in an autocrine or paracrine manner on the cells to induce various IFN-stimulated genes (ISGs), which have antiviral roles. However, the amount of IFN produced depends on the nature of the PRRs used by host cells to detect a particular virus. Although there are many PRRs present in the host cells, their relative contribution in different cell types and against a specific virus may vary. In the first study, we determined the importance of IPS-1 signalling in immunity and pathogenicity of tick-borne flaviviruses. This is an adaptor protein for cytoplasmic RIG-I-like receptors. Using IPS-1-deficient mice, we showed its importance against TBEV and Langat virus (LGTV) infection (the LGTV model virus belongs to the TBEV serogroup). Absence of IPS-1 leads to uncontrolled virus replication in the central nervous system (CNS), but it has only a minor role in shaping the humoral immune response at the periphery. LGTV-infected IPS-1-deficient mice showed apoptosis, activation of microglia and astrocytes, an elevated proinflammatory response, and recruitment of immune cells to the CNS. Interestingly, we also found that IFN-b upregulation after viral infection was dependent on IPS-1 in the olfactory bulb of the brain.  Thus, our results suggest that local immune microenvironment of distinct brain regions is critical for determination of virus permissiveness. Interferons can upregulate several ISGs. Viperin is one such ISG that has a broad-spectrum antiviral action against many viruses. However, the importance of cell type and the significance of viperin in controlling many flavivirus infections in vivo is not known. Using viperin-deficient mice, we found that viperin was necessary for restriction of LGTV replication in the olfactory bulb and cerebrum, but not in the cerebellum. This finding was also confirmed with primary neurons derived from these brain regions. Furthermore, we could also show the particular importance of viperin in cortical neurons against TBEV, WNV, and ZIKV infection. The results suggested that a single ISG can shape the susceptibility and immune response to a flavivirus in different regions of the brain. Although viperin is such an important ISG against flaviviruses, the exact molecular mechanism of action is not known. To understand the mechanism, we performed co-immunoprecipitation screening to identify TBEV proteins that could interact with viperin. While viperin interacted with the prM, E, NS2A, NS2B, and NS3 proteins of TBEV, its interaction with NS3 led to its degradation through the proteosomal pathway. Furthermore, viperin could reduce the stability of other viperin-binding TBEV proteins in an NS3-dependent manner. We screened for viperin activity regarding interaction with NS3 proteins of other flaviviruses. Viperin interacted with NS3 of JEV, ZIKV, and YFV, but selectively degraded NS3 proteins of TBEV and ZIKV, and this activity correlated with its antiviral activity against these viruses. The last study was based on in vivo characterization of the newly isolated MucAr HB 171/11 strain of TBEV which caused unusual gastrointestinal and constitutional symptoms. This strain was compared with another strain, Torö-2003, of the same European subtype of TBEV but isolated from the different focus. Here we found unique differences in their neuroinvasiveness and neurovirulence, and in the immune response to these two strains. In summary, my work shed some light on the interplay between tick-borne flavivirus and the innate immune system. I have shown two examples of CNS region-specific differences in innate immune response regarding both in IFN induction pathways and antiviral effectors. Furthermore, we have investigated the in vivo pathogenesis of a strain of TBEV that caused unusual gastrointestinal and constitutional symptoms. / Flavivirus finns spridda över hela världen och orsakar miljontals infektioner varje år. Några av de medicinsk mest viktiga flavivirusen är fästingburen encefalit virus (TBEV), West Nile virus (WNV), Japansk encefalit virus (JEV), gula febern (YFV) och Zika virus (ZIKV). Dessa virus kan orsaka olika komplikationer till exempel blödarfeber och hjärninflammation. Vid en infektion så upptäcker värdcellen virusinfektionen med hjälp av speciella receptorer, så kallade PRRs. Dessa finns i alla celler och känner igen viruskomponenter som normalt inte finns i en oinfekterad cell. När PRRs detekterar en virusinfektion svarar cellen med att tillverka ett signal protein interferon (IFN). IFN skickas ut ur cellen och hämmar virusinfektioner genom att sätta igång ett försvarsprogram i andra celler bestående av hundratals försvarsproteiner som kan motverka virusinfektionen. Vilka PRRs som behövs för att detektera ett virus är olika vid olika virusinfektioner. I första studien fann vi att IPS-1 är av yttersta vikt för skydda mot fästingburna flavivirus. IPS-1 är ett så kallat adapter protein som behövs för att två PRRs, RIG-I och MDA-5, ska kunna förmedla signaler som leder till IFN tillverkning. Med hjälp av möss som saknar IPS-1 fann vi att IPS-1 behövs för att tillverka IFN protein och skydda mot fästingburna flavivirus. IPS-1 var särskilt viktigt för interferon produktion inom luktloben i hjärnan. Därför kunde vi dra slutsatsen att immunresponsen regleras olika inom olika delar av hjärnan. Ett försvarsprotein som visat sig vara särskilt viktig vid virusinfektion är viperin. Viperin har visat sig kunna hämma en rad olika virus men den specifika rollen av viperin in vivo vid flavivirus infektion var inte fullt känd. Vi fann att viperin behövs för att hämma LGTV i lukloben och storhjärnan men inte i lillhjärnan. Vi kunde bekräfta detta med hjälp av primära nervceller isolerade från dessa hjärnregioner. Vi fann även att viperin var av yttersta vikt för att kontrollera TBEV, WNV och ZIKV infektion i nervceller från hjärnbarken (del av storhjärnan). Därför kunde vi dra slutsatsen att ett enskilt försvarsprotein kan avgöra mottagligheten mot flavivirus inom olika hjärnregioner. Trots att viperin är så viktig för att skydda mot flavivirus så vet vi inte hur viperin åstadkommer detta. Därför ville vi undersöka hur viperin kan förmedla sin antivirala effekt. Vi fann att viperin kan binda till flera TBEV proteiner, men att viperin specifikt kan bryta ner ett virusprotein som heter NS3. NS3 är väldigt viktigt för att flavivirus ska kunna etablera en infektion och kunna föröka sig. Eftersom vi visste att viperin kan hämma andra flavivirus ville vi veta om viperin även förstör NS3 från JEV, ZIKV och YFV. Vi upptäckte att viperin kunde binda till NS3 hos alla dessa flavivirus men att viperin specifikt förstörde TBEV och ZIKV NS3, intressant nog så kunde viperin endast hämma dessa virus infektioner men inte JEV och YFV. I den sista studien ville vi karaktärisera en ny TBEV stam som bara orsakar magoch tarmbesvär men inga neurologiska symptom. TBEV har aldrig tidigare visat sig kunna orsaka detta och därför ville vi undersöka saken vidare. Vi fann att denna TBEV stam skiljde sig mot en närbesläktad stam genom att orsaka en starkare immunrespons men mildare sjukdomsförlopp. Sammanfattningsvis har jag undersökt samspelet mellan fästingburna flavivirus och det medfödda immunförsvaret. Jag har även visat att immunresponsen regleras olika inom olika hjärnregioner, både beträffande IFN inducering och antivirala proteiner. Vidare har jag hittat mekanismen för hur viperin proteinet hämmar TBEV och ZIKV, vilket var genom att förstöra NS3. Dessutom har jag karaktäriserat sjukdomsförloppet hos möss efter infektion med en ovanlig TBEV stam som orsakar mag och tarm besvär.

Orientador: Sonia Maria Oliani / Coorientador: Jusciele Brogin Moreli / Banca: Estela Maris Andrade Forell Bevilacqua / Banca: Flávia Cristina Rodrigues Lisoni / Resumo: Introdução: A associação da infecção por Zika vírus (ZIKV) com malformação congênita e sequelas neurológicas trouxe uma preocupação global significativa. Estudos recentes têm mostrado que a infecção viral induz altos níveis de inflamação nas vilosidades placentárias. Neste contexto, a proteína anti-inflamatória anexina 1 (ANXA1) tem sido avaliada especialmente em células de defesa e associada com atividades antiparasitárias em explantes placentários infectados. Embora esses efeitos tenham sido explorados em diversas investigações, suas atividades ainda não estão completamente esclarecidas em placentas infectadas com ZIKV. Objetivos: Avaliar o envolvimento da proteína ANXA1 em placentas de mães infectadas pelo ZIKV. Materiais e métodos: Com o sangue materno e placentas, usando a técnica PCR em tempo real, foi possível classificar três grupos de estudo: (i) Neg/Neg (mãe e placenta negativas para o vírus), (ii) Pos/Neg (mãe infectada com vírus e placenta negativa) e (iii) Pos/Pos (mãe e placenta infectadas com vírus). Os fragmentos placentários foram fixados, incluídos em parafina e analisados para presença do ZIKV (anti-flavivirus 4g2), estruturalmente e para imunomarcações de células trofoblásticas (citoqueratina), mesenquimais e endoteliais (vimentina) e vasos (α-sma). As células inflamatórias foram analisadas por imunofluorescência e os níveis das citocinas IL-1β, IL-6, IL-10, TNF-α, IL-8 pelo analisador Multiplex Magpix. A expressão da ANXA1 foi avaliada por... / Abstract: Introduction: The association of Zika virus infection (ZIKV) with congenital malformation and neurological sequelae brought a significant global concern. Recent studies have shown that maternal viral infection induces inflammation in the placental tissue. In this context, the antiinflammatory protein annexin 1 (ANXA1) has been specially related to resolution of inflammation through multiple mechanisms and associated with antiparasitic activity in infected placental explants. Although these effects have been explored in several investigations, its activities have not yet been fully elucidated in placentas infected with ZIKV. Objectives: This study was conducted to evaluate the involvement of ANXA1 in placentas of ZIKV-infected mothers. Methods: With maternal blood and placenta, using the rt-PCR techinique, It was classified three study groups: Neg/Neg (mother and placenta negative for the virus), Pos/Neg (infected mother, but no virus detected in placenta) and Pos/Pos (mother and placenta infected with ZIKV). Placental fragments were fixed, embedded in paraffin and analyzed for the presence of ZIKV (anti-flavivirus 4g2), structurally, and immunohistochemistry for trophoblast (cytokeratin), mesenchymal and endothelial cells (vimentin) and arterial vessels (α-sma). Inflammatory cells were analyzed by immunofluorescence (CD-3, CD-15 and CD45 positive cells) and levels of the cytokines IL-1β, IL-6, IL-10, TNF-α, IL-8 by the Magpix Multiplex analyzer. ANXA1 expression was assessed ... / Mestre

<div>The family Flaviviridae includes important genera such as flavivirus and hepacivirus which comprise significant human pathogens that affect hundreds of millions annually. The understanding of these viruses, the viral life cycle, and pathogenicity is vital when it comes to developing therapeutics. Flavivirus virions undergo major conformational rearrangements during the life cycle, including the assembly and maturation steps. In order to create a reagent to investigate these processes, luminescent reporter viruses have been constructed. Luminescent reporter tags have yet to be incorporated into the structural proteins of dengue virus (DENV) without significantly affecting replication or infectivity and successful tagging would allow for targeted studies examining access to specific structural epitopes. Engineering tags in DENV structural proteins is particularly difficult because most reporter tags involve large insertions which may create steric hindrance and inhibit proper protein folding. However, the reporter system described here, developed by Promega, is much smaller than a full-size luciferase protein. It involves an eleven amino acid subunit (HiBiT) tagged to a viral protein that creates measurable luminescence when incubated with the larger subunit (LgBiT). Using the structure of the virion as a guide, the HiBiT reporter tag was incorporated into the structural region of the DENV genome including sites in capsid (C) as well as the glycoproteins membrane (M) and envelope (E). Resulting recombinant viruses were characterized and tag sites within the C protein membrane anchor as well as the transmembrane domain of M protein were found to tolerate HiBiT insertion and produce infectious particles. The recombinant virus possessing HiBiT in C protein was found to be stable over three rounds of serial passaging while virus containing the M protein tag site was found to be unstable. HiBiT activity of the capsid tagged virus was also found to directly correlate with purified infectious particles, suggesting the capsid membrane anchor may remain associated with the virus even after polyprotein processing. Additionally, insert composition was found to be a key determinant for the production of infectious virus. The lessons learned from engineering HiBiT in the DENV system were then applied to hepatitis C virus (HCV). </div><div>The highly lipophilic and pleiomorphic nature of HCV has made structural studies particularly difficult. However, by constructing multi-tagged reporter viruses containing both HiBiT and various purification tags, researchers will save time and resources in preparation for structural studies which are vital for vaccine development. In this study, HiBiT was incorporated into sites within HCV previously shown to tolerate tags of various sizes. Different insert compositions were engineered within the genome and the construct containing both FLAG and HiBiT tags within the N-terminus of E2 yielded highly infectious and quantifiable, luminescent virus. The recombinant HCV containing FLAG and HiBiT displayed similar peak titer as compared to WT while also demonstrating HiBiT activity. Furthermore, the FLAG peptide was found to be partially surface exposed and capable of being used for virus purification purposes. The multi-tagged reporter virus characterized in this study provides a robust platform for quantification and purification of HCV, two facets of research that are critical for the determination of viral structure via cryo-EM and other imaging techniques. The findings from both the DENV and HCV studies provide a robust foundation for future tagging of viruses within the family Flaviviridae and offer insight on the structural proteins that compose the virion.</div>

West Nile Virus (WNV) forms part of the Japanese encephalitis serocomplex in the genus Flavivirus, family Flaviviridae. This enveloped positive single-stranded RNA (+ssRNA ) virus is the etiological agent of West Nile fever, and in more severe cases WNV neuroinvasive disease, in both humans and animals. WNV is distributed worldwide and is phylogenetically classified into five distinct lineages. The WNV genome is ~11 Kb in length and encodes a single open reading frame (ORF) that is post-translationally cleaved into three structural proteins and seven non-structural proteins. In this study, two contemporary and two historic South African WNV strains were genetically characterised as lineage 2 strains based on complete genome sequences. Genetic change as a result of passage number and propagation system was quantified on both the consensus genome- and quasispecies level. A lack of variation was observed amongst the consensus genome sequences of WNV strains subject to changes in propagation system from BHK-21 cell culture to mouse brain and vice versa. In contrast, variation amongst the latter was observed on the quasispecies level. Genome-wide single nucleotide polymorphism (SNP) profiles as well as full-length haplotype sequences reconstructed from ultra deep sequence data indicated that high levels of quasispecies diversity persists, particularly in the capsid gene region, during changes in propagation environment. The changes in frequency of variants were consistent throughout isolates propagated in different systems. The increased variation in the capsid gene region may result from selective pressures brought about by differences in host cell type between propagation systems. This study is the first to demonstrate quasispecies dynamics resulting from changes in propagation system of a lineage 2 WNV based on the reconstruction of full-length haplotype sequences from ultra deep sequence data. The approach demonstrates a cost-effective alternative to the estimation of viral population structure in light of viral evolutionary dynamics, which may in turn be assessed by the single plasmid reverse genetic system designed in this study. Although early attempts at rescuing an infectious WNV clone were unsuccessful, the system shows promise in the application of future studies concerning vaccine and diagnostic development, virulence studies and disease control. / Dissertation (MSc)--University of Pretoria, 2013. / gm2013 / Zoology and Entomology / Unrestricted

Das Dengue-Virus ist ein, in tropischen und subtropischen Regionen endemisches, humanpathogenes Virus, welches durch Moskitos des Genus Aedes übertragen wird. Jährlich werden ca. 95 Millionen der Infektionen klinisch manifestiert, wobei 1 % davon in der schwersten Form des Dengue-hämorrhagischen Fiebers verlaufen. Eine schnelle und einfache Diagnostik spielt dabei für die Behandlung sowie für epidemiologische Studien eine wichtige Rolle. Die serologische Diagnostik flaviviraler Infektionen im Allgemeinen und DENV im Speziellen, ist durch die Vielzahl kreuzreaktiver und infektionsverstärkender Antikörper hoch komplex. Die starke Co-Zirkulation verschiedener Flaviviren und deren ähnliche klinische Symptomatik erschwert zusätzlich die spezifische Diagnostik. Seit 2015 führte insbesondere der massive Vormarsch von ZIKV‑Infektionen in DENV-endemischen Gebieten Südamerikas zu einer noch komplexeren Sachlage, da die serologische Unterscheidung beider Infektionen kaum möglich war. Im Rahmen dieser Promotionsarbeit wurden daher rekombinante virale E-Proteine exprimiert und charakterisiert, welche die Spezifität serologischer DENV- und ZIKV‑Tests erhöhen sollen. E-Proteine sind stark immunogen, da sie die Virusoberfläche dominieren. Jedoch ist deren hochkonservierte DII-FL Region gleichzeitig das Ziel von einem Großteil kreuzreaktiver Antikörper. Studien mit WNV und JEV haben zuvor belegt, dass Mutationen in diesem Sequenzbereich, die Kreuzreaktivität mit heterologen Flaviviren herabsenken können. Deshalb wurden vier Punktmutationen in die DII-FL Region von DENV 1-4 und ZIKV E (Equad) eingefügt und in einem Insektentenzellen- basierten System exprimiert, aus dem Kulturüberstand aufgereinigt und mit Humanseren in IgM- und IgG-ELISAs untersucht. Die Ergebnisse dieser Arbeit werden in zwei Publikationen dargelegt, welche die Grundlage für diese Promotionsschrift darstellen.

Through the SARS-CoV-2 pandemic, it has become clear that the development of antivirals is essential for the health and wellbeing of the population. In this study, novel active site protease inhibitors against SARS-CoV-2 were tested for their inhibitory activity against the viral 3-Chymotrypsin like protease through the means of FRET based enzymatic assays. Additionally, Compound 104 targeting the NS2B-NS3 protease was tested against Zika virus through yield reduction assays as a means to assess whether these assays are suitable for the assessment of peptide hybrid compounds in Zika virus.Novel compounds against SARS-CoV-2 were screened and five of the selected six active compounds were found to inhibit the viral protease at a half-maximal inhibitory concentration (IC50) of below 0.075 µM.In Zika virus, the yield reduction assay was assessed and it was found that under the conditions tested, this assay is not suitable for the assessment of peptide hybrid compounds in Zika virus.The active novel compounds against SARS-CoV-2 should be taken for further assessment in cell based assays as the next step of development. Compound 104 should be assessed under different experimental conditions to identify whether different conditions can make this assay suitable for the intended use.

Tick-borne encephalitis (TBE) is one of the most important viral zoonosis caused by a neurotropic arbovirus (TBEV). In Germany, TBE is classified as a notifiable disease with an average of 350 autochthonous human cases annually. The incidence-based risk assessment in Germany came under criticism because every year, a number of autochthonous human TBE cases have been detected outside of the official risk areas. Therefore, it is necessary to find additional parameters to strengthen TBEV surveillance. The aim of this study was to examine red foxes as sentinels for TBE. Thus far, there are no published data about the sensitivity and specificity for serological methods testing fox samples. Hence, we aimed to define a system for the screening of TBEV-specific antibodies in red foxes. A total of 1233 fox sera were collected and examined by ELISA and IIFA and confirmed by micro-NT. The overall seroprevalence of antibodies against TBEV in red foxes from Germany confirmed by micro-NT was 21.1%. The seroprevalence differed significantly between risk (30.5%) and non-risk areas (13.1%), with good correlations to local TBE incidence in humans. In conclusion, serological monitoring of red foxes represents a promising surrogate marker system and may even determine unexpected TBEV foci in regions currently regarded as non-risk areas.