A selection and optimization strategy for single-domain antibodies targeting the PHF6 linear peptide within the tau intrinsically disordered protein.

The use of variable domain of the heavy-chain of the heavy-chain-only antibodies (VHHs) as disease-modifying biomolecules in neurodegenerative disorders holds promises, including targeting of aggregation-sensitive proteins. Exploitation of their clinical values depends however on the capacity to deliver VHHs with optimal physico-chemical properties for their specific context of use. We described previously a VHH with high therapeutic potential in a family of neurodegenerative diseases called tauopathies. The activity of this promising parent VHH named Z70 relies on its binding within the central region of the tau protein. Accordingly, we carried out random mutagenesis followed by yeast two-hybrid screening to obtain optimized variants. The VHHs selected from this initial screen targeted the same epitope as VHH Z70 as shown using NMR spectroscopy and had indeed improved binding affinities according to dissociation constant values obtained by surface plasmon resonance spectroscopy. The improved affinities can be partially rationalized based on three-dimensional structures and NMR data of three complexes consisting of an optimized VHH and a peptide containing the tau epitope. Interestingly, the ability of the VHH variants to inhibit tau aggregation and seeding could not be predicted from their affinity alone. We indeed showed that the in vitro and in cellulo VHH stabilities are other limiting key factors to their efficacy. Our results demonstrate that only a complete pipeline of experiments, here described, permits a rational selection of optimized VHH variants, resulting in the selection of VHH variants with higher affinities and/or acting against tau seeding in cell models.

Epidemiological and clinical insights into the enterovirus D68 upsurge in Europe 2021/22 and the emergence of novel B3-derived lineages, ENPEN multicentre study.

Enterovirus D68 (EV-D68) infections are associated with severe respiratory disease and acute flaccid myelitis (AFM). The European Non-Polio Enterovirus Network (ENPEN) aimed to investigate the epidemiological and genetic characteristics of EV-D68 and its clinical impact during the fall-winter season of 2021/22. From 19 European countries, 58 institutes reported 10,481 (6.8%) EV-positive samples of which 1,004 (9.6%) were identified as EV-D68 (852 respiratory samples). Clinical data was reported for 969 cases. 78.9% of infections were reported in children (0-5 years); 37.9% of cases were hospitalised. Acute respiratory distress was commonly noted (93.1%) followed by fever (49.4%). Neurological problems were observed in 6.4% of cases with six reported with AFM. Phylodynamic/Nextstrain and phylogenetic analyses based on 694 sequences showed the emergence of two novel B3-derived lineages, with no regional clustering. In conclusion, we describe a large-scale EV-D68 European upsurge with severe clinical impact and the emergence of B3-derived lineages.

Circulation, viral diversity and genomic rearrangement in mpox virus in the Netherlands during the 2022 outbreak and beyond.

Mpox is an emerging zoonotic disease which has now spread to over 113 countries as of August 2023, with over 89,500 confirmed human cases. The Netherlands had one of the highest incidence rates in Europe during the peak of the outbreak. In this study, we generated 158 near-complete mpox virus (MPXV) genomes (12.4% of nationwide cases) that were collected throughout the Netherlands from the start of the outbreak in May 2022 to August 2023 to track viral evolution and investigate outbreak dynamics. We detected 14 different viral lineages, suggesting multiple introductions followed by rapid initial spread within the country. The estimated evolutionary rate was relatively high compared to previously described in orthopoxvirus literature, with an estimated 11.58 mutations per year. Genomic rearrangement events occurred at a rate of 0.63% and featured a large deletion event. In addition, based on phylogenetics, we identified multiple potential transmission clusters which could be supported by direct source- and contact tracing data. This led to the identification of at least two main transmission locations at the beginning of the outbreak. We conclude that whole genome sequencing of MPXV is essential to enhance our understanding of outbreak dynamics and evolution of a relatively understudied and emerging zoonotic pathogen.

Internet Addiction, Sleep Habits and Family Communication: The Perspectives of a Sample of Adolescents.

BACKGROUND: With the increase in communication technologies, the internet has become an indispensable tool in the life of the individual. Several studies report on the advantages of this resource; however, there is still a group of individuals who use the internet excessively. The aim of this study was to explore the relationships between internet addiction, daytime sleepiness, and family communication in adolescents. METHODS: A total of 340 adolescents aged between 12 and 17 years participated in this study. All completed the sociodemographic questionnaire, the internet addiction test, the pediatric daytime sleepiness scale, and the family communication scale. RESULTS: The results indicate that 64.1% of the adolescents had mild to moderate addiction to the internet. The main results suggest that internet addiction in adolescents is negatively associated with family communication and positively associated with excessive daytime sleepiness. It was also observed that gender had a significant effect on daytime sleepiness, with female participants having more excessive daytime sleepiness. Regarding age, the results indicate higher values of internet addiction among younger adolescents. CONCLUSIONS: In view of the above, it is considered important to develop preventive actions with a view to healthy family communication, with the adoption of sleep hygiene habits and the promotion of healthy use of the internet.

Evaluating the contribution of antimicrobial use in farmed animals to global antimicrobial resistance in humans.

Antimicrobial resistance (AMR) is currently regarded by the World Health Organization (WHO) as one of the most significant risks to global public health. The most critical causes of AMR infections in humans are the misuse and overuse of antimicrobials in humans and farmed animals. The rising global demand for food of animal origin encourages the increase of animal production worldwide, especially in developing countries. Simultaneously, current farming practices often extensively use antimicrobials on animals, influencing bacterial AMR incidence. This study aims to evaluate the correlation between antimicrobial use (AMU) in farmed animals and the detection of AMR infections in humans, the effects of enforcing laws in animal farming in a country on AMR situation in the neighbors, and the potential of AMR to spread from one country to another. Using data from 30 largest animal-producing countries in different regions of the world, between 2010 and 2020, and a Spatial Durbin Model (SDM), we found that AMU in farmed animals increases AMR in humans and there is a spatial dependence between countries regarding AMR spreading. Such findings indicate that a globally coordinated strategy regulating AMU on farmed animals may reduce AMR emergence and worldwide spreading.

Adaptação e análise da estrutura interna da Escala de Mobbing de Leymann (LIPT45) para o contexto português / Adaptation and analysis of the internal structure of the Leymann Inventory of Psychological Terror (LIPT45) for the Portuguese context / Adaptación y análisis de la estructura interna de la escala de mobbing de Leymann (LIPT45) para el contexto portugués

O objetivo deste trabalho consiste em adaptar e analisar a estrutura interna da versão portuguesa do Leymann Inventory of Psychological Terror (LIPT45). Foi utilizada uma amostra de 404 indivíduos (70,5% mulheres) entre os 18 e os 69 anos (M = 32,9; DP = 12.606). O LIPT45-PV é uma escala de autorrelato composta por 45 itens que avaliam o assédio moral nas organizações, divididos em cinco dimensões: efeitos na autoexpressão; efeitos sobre os contatos sociais; efeitos sobre a reputação pessoal; efeitos sobre a situação ocupacional e qualidade de vida, e efeitos sobre a saúde. Foi utilizada uma análise fatorial confirmatória e o Exploratory Structural Equation Modeling (ESEM), mediante os quais se avaliou um modelo de cinco dimensões, além da confiabilidade do construto e das pontuações. Em conformidade com os resultados da ESEM, o LIPT45-PV apresenta uma estrutura fatorial coerente, assim como uma maior diferenciação entre as suas dimensões. Da mesma forma, os indicadores de confiabilidade do construto e das pontuações foram adequados. Conclui-se que o LIPT45-PV revela características psicométricas (estrutura interna e confiabilidade) que o configura como um instrumento adequado para avaliar o respetivo constructo em adultos.(AU)

The aim of this work was to adapt and analyze the internal structure of the Portuguese version of the Leymann Inventory of Psychological Terror (LIPT45). A sample of 404 individuals (70.5% women) aged between 18 and 69 years (M = 32.9; SD = 12.606) was used. The LIPT45-PV is a self-report scale composed by 45 items that assess mobbing in organizations, divided into five dimensions: effects on self-expression; effects on social contacts; effects on personal reputation; effects on the occupational situation and quality of life, and effects on health. Confirmatory factor analysis and Exploratory Structural Equation Modeling (ESEM) were used, through which a five-dimensional model was evaluated, as well as the reliability of the construct and the scores. According to the results of the ESEM, the LIPT45-PV presents a coherent factor structure, as well as greater differentiation between its dimensions. Likewise, the reliability indicators of the construct and the results were adequate. We can conclude that the LIPT45-PV reveals psychometric characteristics (internal structure and reliability) that configure it as an adequate instrument to evaluate the respective construct in adults.(AU)

El objetivo de este trabajo consiste en adaptar y analizar la estructura interna de la versión portuguesa del Leymann Inventory of Psychological Terror (LIPT45). Fue utilizada una muestra de 404 individuos (70.5% mujeres) entre los 18 y 69 años (M= 32.9; DS = 12.606). El LIPT45-PV es una escala de autoinforme compuesta por 45 ítems que evalúan el acoso laboral en las organizaciones, divididos en cinco dimensiones: efectos en la autoexpresión; efectos sobre los contactos sociales; efectos sobre la reputación personal; efectos sobre la situación ocupacional y calidad de vida, y efectos sobre la salud. Fue utilizado un análisis factorial confirmatorio y el Exploratory Structural Equation Modeling (ESEM), a través de los cuales se evaluó un modelo de cinco dimensiones, además de la confiabilidad del constructo y de las puntuaciones. De acuerdo con los resultados del ESEM, el LIPT45-PV presenta una estructura factorial coherente, así como una mayor diferenciación entre sus dimensiones. Asimismo, los indicadores de confiabilidad del constructo y de las puntuaciones fueron adecuados. Se concluye que el LIPT45-PV presenta características psicométricas (estructura interna y confiabilidad) que lo configuran como un instrumento adecuado para evaluar el constructo mencionado en adultos.(AU)

Towards the Generation of an ASFV-pA104R DISC Mutant and a Complementary Cell Line-A Potential Methodology for the Production of a Vaccine Candidate.

African swine fever (ASF) is a fatal viral disease of domestic swine and wild boar, considered one of the main threats for global pig husbandry. Despite enormous efforts, to date, neither the classical vaccine formulations nor the use of protein subunits proved to be efficient to prevent this disease. Under this scenario, new strategies have been proposed including the development of disabled infectious single cycle (DISC) or replication-defective mutants as potential immunizing agents against the ASF virus (ASFV). In this study, we describe the methodology to generate an ASFV-DISC mutant by homologous recombination, lacking the A104R gene, which was replaced by the selection marker (GUS gene). The recombinant viruses were identified when the infected cells acquired a blue color in the presence of X-Gluc (100 µg/mL), which is the substrate for the GUS gene. Since these viral particles result from loss-of-function mutations, being unable to replicate, helper-cell lines expressing the viral pA104R protein were produced. Vero and COS-1 cell lines were transfected by different methods, both physical and chemical, in order to stably express the ASFV-pA104R. Best results were obtained by using Lipofectamine 2000 and Nucleofection methodology of Vero with the pIRESneo vector and by using Flp-FRT site-directed recombination technology system in Flp-In CV-1 cells (transformed COS-1 cells with a single integration site in a transcriptional active region). In order to ensure an efficient and stable integration of the viral ORF on the host cellular genome, the maintenance of the insert was verified by PCR and its expression by immunofluorescence and immunoblot analysis. Although the isolation of the recombinant virus was not achieved, the confirmation of ASFV-ΔA104R sequence, and the detection of the recombinant mutant through three passages, suggest that this approach is feasible and could be a potential strategy to generate safe and efficient DISC vaccine candidates.

African swine fever virus replication events and cell nucleus: New insights and perspectives.

African swine fever (ASF) is currently matter for major concerns in global swine industry as it is highly contagious and causes acute fatal haemorrhagic fever in domestic pigs and wild boar. The absence of effective vaccines and treatments pushes ASF control to relay on strict sanitary and stamping out measures with costly socio-economic impacts. The current epidemic scenario of fast spreading throughout Asiatic countries impels further studies on prevention and combat strategies against ASF. Herein we review knowledge on African Swine Fever Virus (ASFV) interactions with the host cell nucleus and on the functional properties of different viral DNA-replication related proteins. This entails, the confirmation of an intranuclear viral DNA replication phase, the characterization of cellular DNA damage responses (DDR), the subnuclear compartments disruption due to viral modulation, and the unravelling of the biological role of several viral proteins (A104R, I215 L, P1192R, QP509 L and Q706 L), so to contribute to underpin rational strategies for vaccine candidates development.

Low-frequency noise effects on the rat parotid gland: A transmission electron microscopy study.

INTRODUCTION: Low-frequency noise (LFN) is a ubiquitous physical stressor known to cause degenerative cellular changes and organ alterations with functional repercussions both in humans and animals. MATERIALS AND METHODS: After acceptance of the study protocol by a local ethics committee, 20 Wistar rats were randomly divided into two equal groups. One group was kept in silence and the other continuously exposed to LFN during 13 weeks. The rats had unlimited access to water and were fed standard rat chow. After exposure, the animals were sacrificed and the parotid glands were excised and prepared for transmission electron microscopy. RESULTS: The acinar cells showed marked ultrastructural alterations, such as intracellular vacuolization, loss of cell polarity, increased heterochromatin, cytoplasmic inclusions, and oncocytic transformation. CONCLUSIONS: LFN induces ultrastructural changes in the rat parotid gland that correlate with previously described functional changes.

International note: Confirmatory factor analysis and psychometric properties of the Youth Psychopathic Traits Inventory in a sample of Portuguese adolescents.

The aim of this paper was to test the factorial structure and evaluate the psychometric properties of the Youth Psychopathic Traits Inventory (YPI). The YPI is composed of 10 dimensions that further represent three hypothesized facets of the classical description of psychopathy: callousness, interpersonal manipulation and impulsiveness. A sample of 500 adolescents aged 12 to 18 (M = 14.87; SD = 1.67) from northern Portugal participated in this study. The results generally confirmed the factorial structure of the YPI in this sample, with some qualifications.

Alterations of Nuclear Architecture and Epigenetic Signatures during African Swine Fever Virus Infection.

Viral interactions with host nucleus have been thoroughly studied, clarifying molecular mechanisms and providing new antiviral targets. Considering that African swine fever virus (ASFV) intranuclear phase of infection is poorly understood, viral interplay with subnuclear domains and chromatin architecture were addressed. Nuclear speckles, Cajal bodies, and promyelocytic leukaemia nuclear bodies (PML-NBs) were evaluated by immunofluorescence microscopy and Western blot. Further, efficient PML protein knockdown by shRNA lentiviral transduction was used to determine PML-NBs relevance during infection. Nuclear distribution of different histone H3 methylation marks at lysine's 9, 27 and 36, heterochromatin protein 1 isoforms (HP1α, HPß and HPγ) and several histone deacetylases (HDACs) were also evaluated to assess chromatin status of the host. Our results reveal morphological disruption of all studied subnuclear domains and severe reduction of viral progeny in PML-knockdown cells. ASFV promotes H3K9me3 and HP1ß foci formation from early infection, followed by HP1α and HDAC2 nuclear enrichment, suggesting heterochromatinization of host genome. Finally, closeness between DNA damage response factors, disrupted PML-NBs, and virus-induced heterochromatic regions were identified. In sum, our results demonstrate that ASFV orchestrates spatio-temporal nuclear rearrangements, changing subnuclear domains, relocating Ataxia Telangiectasia Mutated Rad-3 related (ATR)-related factors and promoting heterochromatinization, probably controlling transcription, repressing host gene expression, and favouring viral replication.

Early intranuclear replication of African swine fever virus genome modifies the landscape of the host cell nucleus.

Although African swine fever virus (ASFV) replicates in viral cytoplasmic factories, the presence of viral DNA within the host cell nucleus has been previously reported to be essential for productive infection. Herein, we described, for the first time, the intranuclear distribution patterns of viral DNA replication events, preceding those that occur in the cytoplasmic compartment. Using BrdU pulse-labelling experiments, newly synthesized ASFV genomes were exclusively detected inside the host cell nucleus at the early phase of infection, both in swine monocyte-derived macrophages (MDMs) and Vero cells. From 8hpi onwards, BrdU labelling was only observed in ASFV cytoplasmic factories. Our results also show that ASFV specifically activates the Ataxia Telangiectasia Mutated Rad-3 related (ATR) pathway in ASFV-infected swine MDMs from the early phase of infection, most probably because ASFV genome is recognized as foreign DNA. Morphological changes of promyelocytic leukaemia nuclear bodies (PML-NBs), nuclear speckles and Cajal bodies were also found in ASFV-infected swine MDMs, strongly suggesting the viral modulation of cellular antiviral responses and cellular transcription, respectively. As described for other viral infections, the nuclear reorganization that takes place during ASFV infection may also provide an environment that favours its intranuclear replication events. Altogether, our results contribute for a better understanding of ASFV replication strategies, starting with an essential intranuclear DNA replication phase which induces host nucleus changes towards a successful viral infection.

First report of Anaplasma platys infection in red foxes (Vulpes vulpes) and molecular detection of Ehrlichia canis and Leishmania infantum in foxes from Portugal.

BACKGROUND: The bacteria Anaplasma platys and Ehrlichia canis and the protozoan Leishmania infantum are vector-borne agents that cause canine vector-borne diseases, some of which are zoonotic. The present survey investigated the prevalence of Anaplasma, Ehrlichia and Leishmania in red foxes (Vulpes vulpes) from Portugal by molecular analysis, in order to evaluate the epidemiological role of these canids as reservoirs of infection. METHODS: Blood and/or bone marrow samples were collected from 78 red foxes obtained in eight districts of northern, central and southern Portugal. Real-time polymerase chain reactions (PCR) amplified a 123 bp fragment of the 16S rRNA gene of Anaplasma spp. and Ehrlichia spp. and a 265 bp fragment of the L. infantum internal transcribed spacer one (ITS1) region of the rRNA operon evaluated by PCR-high resolution melt analysis (PCR-HRM), with sequencing of the DNA products. A phylogenetic analysis was carried out to compare these to other sequences from Anaplasma spp. and Ehrlichia spp. deposited in GenBank. RESULTS: A. platys was detected in 10 (14.5%) and E. canis in two (2.9%) out of 69 foxes; and L. infantum was detected in one (1.3%) of the 78 foxes. The prevalence of A. platys was significantly different from the prevalence of E. canis (p=0.016) and from that of L. infantum (p=0.002). No co-infections were found in any one of the 78 foxes. No statistically significant differences were found between the type of sample (blood and bone marrow), geographic regions (north/centre and south), age (<2 years and ≥2 years) and gender for any one of the agents. CONCLUSIONS: This is the first known report of A. platys in red foxes worldwide, as well as the first molecular evidence of E. canis in foxes from Portugal. The moderate prevalence of A. platys suggests that red foxes may play a role in the epidemiology of infection with this bacterium and serve as a reservoir for domestic dogs.

[European Portuguese EARS test battery adaptation]. / Adaptação da bateria de testes EARS ao Português Europeu.

INTRODUCTION: The use of adequate assessment tools in health care is crucial for the management of care. The lack of specific tools in Portugal for assessing the performance of children who use cochlear implants motivated the translation and adaptation of the EARS (Evaluation of Auditory Responses to Speech) test battery into European Portuguese. This test battery is today one of the most commonly used by (re)habilitation teams of deaf children who use cochlear implants worldwide. The goal to be achieved with the validation of EARS was to provide (re)habilitation teams an instrument that enables: (i) monitoring the progress of individual (re)habilitation, (ii) managing a (re)habilitation program according to objective results, comparable between different (re)habilitation teams, (iii) obtaining data that can be compared with the results of international teams, and (iv) improving engagement and motivation of the family and other professionals from local teams. MATERIAL AND METHODS: For the test battery translation and adaptation process, the adopted procedures were the following: (i) translation of the English version into European Portuguese by a professional translator, (ii) revision of the translation performed by an expert panel, including doctors, speech-language pathologists and audiologists, (iii) adaptation of the test stimuli by the team's speechlanguage pathologist, and (iv) further review by the expert panel. RESULTS: For each of the tests that belong to the EARS battery, the introduced adaptations and adjustments are presented, combining the characteristics and objectives of the original tests with the linguistic and cultural specificities of the Portuguese population. DISCUSSION: The difficulties that have been encountered during the translation and adaptation process and the adopted solutions are discussed. Comparisons are made with other versions of the EARS battery. CONCLUSION: We defend that the translation and the adaptation process followed for the EARS test battery into European Portuguese was correctly conducted, respecting the characteristics of the original instruments and adapting the test stimuli to the linguistic and cultural reality of the Portuguese population, thus meeting the goals that have been set.

Introdução: A utilização de instrumentos de avaliação em saúde adequados é fundamental na gestão da prestação de cuidados. A escassez, em Portugal, de instrumentos específicos para a avaliação do desempenho de crianças utilizadoras de implantes cocleares motivou o trabalho de tradução e de adaptação da bateria de testes EARS (Evaluation of Auditory Responses to Speech) para o português europeu. Esta bateria de testes é hoje um dos instrumentos mais comummente utilizados por equipas de (re)habilitação de crianças surdas com implantes cocleares em todo o mundo. O objetivo a atingir com a validação do EARS foi fornecer às equipas de (re)habilitação um instrumento que permita: (i) monitorizar a evolução individual da reabilitação; (ii) gerir um programa de (re)habilitação de acordo com resultados objetivos, comparáveis entre diferentes equipas de (re)habilitação; (iii) obter dados comparáveis comequipas internacionais; e (iv) melhorar a adesão e a motivação da família e restantes profissionais no ambulatório.Material e Métodos: No processo de tradução e de adaptação da bateria de testes, os procedimentos adotados foram os seguintes: (i) tradução da versão inglesa para português europeu por um tradutor profissional; (ii) revisão dessa tradução realizada por um painel de especialistas constituído por otorrinolaringologistas, terapeutas da fala e técnicos de audiologia; (iii) adaptação dos estímulos de teste pela equipa de terapeutas da fala; e (iv) nova revisão por parte do painel de especialistas.Resultados: São apresentados, para cada um dos instrumentos que compõem a bateria EARS, as adaptações introduzidas, conciliando as características e os objetivos originais dos instrumentos com as particularidades linguísticas e culturais da população portuguesa.Discussão: São discutidas as dificuldades encontradas durante o processo de tradução e de adaptação e as soluções adotadas. São feitas comparações com outras versões da bateria EARS.Conclusão: Considera-se que o processo de tradução e adaptação da bateria de testes EARS para o português europeu foi realizado de forma apropriada, respeitando as características dos instrumentos originais e adequando os estímulos de teste à realidade linguística e cultural da população portuguesa, cumprindo assim os objetivos propostos.

Feline HER2 protein expression levels and gene status in feline mammary carcinoma: optimization of immunohistochemistry (IHC) and in situ hybridization (ISH) techniques.

Human epidermal growth factor receptor (HER2) is a tumor biomarker that when overexpressed and/or amplified is associated with a poor prognosis for women with breast cancer. This specific tumor subtype is eligible for a specific immunotherapy that increases survival period. However, in feline oncology, only a few studies have been performed on molecular characterization of feline (fHER2) in feline mammary carcinoma (FMC), and the available data are inconsistent. In this study, fHER2 protein levels and gene status in FMC were evaluated by immunohistochemistry and in situ hybridization. After being optimized, these techniques revealed that fHER2 is overexpressed in 33% of FMC cases, although fHER2 and fTOP2A gene amplification could not be observed. Our results support the possibility of using FMC as a natural model for comparative oncology. Additional data obtained may also improve the diagnostics, and consequently the treatment, of this type of tumor in veterinary medicine.

Host DNA damage response facilitates African swine fever virus infection.

Studies with different viral infection models on virus interactions with the host cell nucleus have opened new perspectives on our understanding of the molecular basis of these interactions in African swine fever virus (ASFV) infection. The present study aims to characterize the host DNA damage response (DDR) occurring upon in vitro infection with the ASFV-Ba71V isolate. We evaluated protein levels during ASFV time-course infection, of several signalling cascade factors belonging to DDR pathways involved in double strand break repair - Ataxia Telangiectasia Mutated (ATM), ATM-Rad 3 related (ATR) and DNA dependent protein kinase catalytic subunit (DNA-PKcs). DDR inhibitory trials using caffeine and wortmannin and ATR inducible-expression cell lines were used to confirm specific pathway activation during viral infection. Our results show that ASFV specifically elicits ATR-mediated pathway activation from the early phase of infection with increased levels of H2AX, RPA32, p53, ATR and Chk1 phosphorylated forms. Viral p72 synthesis was abrogated by ATR kinase inhibitors and also in ATR-kd cells. Furthermore, a reduction of viral progeny was identified in these cells when compared to the outcome of infection in ATR-wt. Overall, our results strongly suggest that the ATR pathway plays an essential role for successful ASFV infection of host cells.

In vitro antiviral activity of fluoroquinolones against African swine fever virus.

African swine fever (ASF) is a viral swine disease against which neither an effective vaccine nor a treatment is available. The antiviral effect of thirty fluoroquinolones on the infectivity of African swine fever virus (ASFV) was screened in vitro. There was a severe reduction of the cytopathic effect in ASFV-infected Vero cells when exposed to six independent fluoroquinolones, or to some of their combinations, from an early phase of infection. Moreover, after 7-day treatments, ASFV genome could not be detected by PCR, and the culture supernatants were unable to infect new cell cultures. Pulsed field gel electrophoresis (PFGE) analysis revealed a diminished viral DNA replication without identifiable genome fragmentation in cells exposed to fluoroquinolones. In parallel, altered patterns of viral protein synthesis were observed from early infection. The overall results indicate that bacterial topoisomerase inhibitors interfere with the ASFV replication cycle probably by targeting a putative ASFV-topoisomerase II, opening a new window for antiviral treatments.