Enzootic epidemiology of Brucella in livestock in central Gansu Province after the National Brucellosis Prevention and Control Plan

Brucellosis remains one of the most common zoonoses spread worldwide,inducing enormous economic losses to the livestock industry and posing serious health threats to humans.Brucellosis re-emerged in China in the mid-1990s and reached a historically high level in 2015.The National Brucellosis Prevention and Control Plan(NBPCP)was initiated from 2016 to 2020.However,the present epidemiological status in livestock has not been elucidated,and whether Brucella variation occurred remains unclear.This study performed an extensive serological investigation in ruminant livestock from 2019 to 2021 in central Gansu Province,China.In total,11,296 samples from 337 farms were collected to detect the specific antibodies of Brucella.The yearly average serological prevalence of Brucella at the flock level and individual level declined from 11.32%to 8.26%and 1.17%to 0.57%,respectively.The apparent individuallevel seroprevalence of small and large ruminants was 0.89%and 0.52%,respectively.The brucellosis distribution has shifted from pastoral areas to agro-pastoral areas.Flock size and gender may be major risks of Brucella infection.Then,the B.melitensis TZ strain was isolated from female Tibetan sheep blood cell lysates.Phonotypical characterization demonstrated that it belongs to B.melitensis.biovar 3,and multilocus sequencing typing results indicated that it belongs to ST8.The whole genome and subsequent phylogenetic analysis demonstrated that the B.melitensis TZ strain is genetically more closely related to the B.melitensis QH61 strain.The B.melitensis TZ strain has similar growth characteristics to the B.melitensis 16 M strain.Overall,our study suggests that after strengthening control and prevention measures based on the NBPCP,there is a very low prevalence or absence of B.melitensis in the central Gansu Province of China,and the genotype of an epidemic strain of Brucella in Northwest China is relatively stable.

Altered gene expression in human brain microvascular endothelial cells in response to the infection of influenza H1N1 virus

Influenza viruses not only cause respiratory illness,but also have been reported to elicit neurological manifestations following acute viral infection.The central nervous system(CNS)has a specific defense mechanism against pathogens structured by cerebral microvasculature lined with brain endothelial cells to form the blood–brain barrier(BBB).To investigate the response of human brain microvascular endothelial cells(hBMECs)to the Influenza A virus(IAV),we inoculated the cells with the A/WSN/33(H1N1)virus.We then conducted an RNAseq experiment to determine the changes in gene expression levels and the activated disease pathways following infection.The analysis revealed an effective activation of the innate immune defense by inducing the pattern recognition receptors(PRRs).Along with the production of proinflammatory cytokines,we detected an upregulation of interferons and interferon-stimulated genes,such as IFN-β/λ,ISG15,CXCL11,CXCL3 and IL-6,etc.Moreover,infected hBMECs exhibited a disruption in the cytoskeletal structure both on the transcriptomic and cytological levels.The RNAseq analysis showed different pathways and candidate genes associated with the neuroactive ligand-receptor interaction,neuroinflammation,and neurodegenerative diseases,together with a predicted activation of the neuroglia.Likewise,some genes linked with the mitochondrial structure and function displayed a significantly altered expression.En masse,this data supports that hBMECs could be infected by the IAV,which induces the innate and inflammatory immune response.The results suggest that the influenza virus infection could potentially induce a subsequent aggravation of neurological disorders.

Pig macrophages with site-specific edited CD163 decrease the susceptibility to infection with porcine reproductive and respiratory syndrome virus

Porcine reproductive and respiratory syndrome(PRRS)is recognized as one of the most infectious viral diseases of swine.Although Cluster of differentiation 163(CD163)is identified as an essential receptor for mediating PRRS virus(PRRSV)infection,the important residues involved in infection on CD163 are still unclear.Therefore,it is very important to identify these key residues to study the mechanism of PRRSV infection and to generate anti-PRRSV pigs.In this study,we first generated immortalized porcine alveolar macrophage(IPAM)cell lines harboring 40-residues(residues 523-562,including R561(arginine(R)at position 561))deletion of CD163.PRRSV infection experiments showed that these IPAM cell lines were completely resistant to PRRSV infection.We then generated cloned pigs carrying CD163-R561A(an arginine(R)to alanine(A)substitution at position 561 of CD163).PRRSV challenge experiments in porcine alveolar macrophages(PAMs)isolated from the CD163-R561A pigs showed significantly lower susceptibility to PRRSV than that of CD163-R561 PAMs.Through this study,we show that CD163523-562 contains essential residues for mediating PRRSV infection,and that CD163 R561 significantly contributes to PRRSV infection but is not essential for infection.These functional sites can therefore serve as new targets for understanding the mechanism of PRRSV infection.Furthermore,CD163-R561A pigs can be used as an important model for improving pig germplasm with resistance against PRRSV.

Epidemiological trends of mosquito-borne viral diseases in Pakistan

Globally,arboviruses are public health problems.Pakistan has seen a fast-paced increase in mosquito-borne Flavivirus diseases such as dengue because of deforestation,climate change,urbanization,poor sanitation and natural disasters.The magnitude and distribution of these diseases are poorly understood due to the lack of a competitive nationwide surveillance system.In dengue-endemic countries,the recent epidemics of chikungunya(CHIKV)and human West Nile virus(WNV)have created panic among the public and are thought to provoke an outbreak of Zika virus(ZIKV)in Pakistan.Recently,hospital-based surveillance has indicated the presence of Japanese encephalitis virus(JEV),which is deeply concerned by developing countries such as Pakistan.The situation could become more devastating because of poorly developed diagnostic infrastructure.To date,no licensed vaccine has been used in Pakistan,and preventive measures are mainly based on vector control.This review provides comprehensive information concerning the association of risk factors with disease occurrence,epidemiological trends,and prediction of the spread of mosquito-borne diseases,attention to new threats of ZIKV,and future perspectives by benchmarking global health policies.

Characteristics of colistin-resistant Escherichia coli from pig farms in Central China

The emergence and dissemination of colistin resistance in Enterobacterioceae mediated by plasmid-borne mcr genes in recent years now pose a threat to public health.In this study,we isolated and characterized colistin-resistant and for mcr-positive£coli from pig farms in Central China.Between 2018 and 2019,594 samples were collected and recovered 445 E.coli isolates.Among them,33 with colistin resistance phenotypes and 37 that were positive for mcr genes were identified,including 34 positive for mcr-1,one positive for mcr-3,and two positive for both mcr-1 and mcr-3.An insertion of nine bases("CTGGATACG")into mcr-7 in four mcr-positive isolates led to gene dysfunction,and therefore did not confer the colistin resistance phenotype.Antimicrobial susceptibility testing revealed that 37 mcr-positive isolates showed severe drug resistance profiles,as 50% of them were resistant to 20 types of antibiotics.Multilocus sequence typing revealed a heterogeneous group of sequence types in mcr-positive isolates,among which ST10(5/37),ST156(5/37),and 5T617(4/37)were the predominant types.Plasmid conjugation assays showed that mcr-carrying plasmids of 25 mcr-positive isolates were conjugated with£coli recipient,with conjugation frequencies ranging from 1.7 × 10^(-6) to 4.1 × 10^(-3) per recipient.Conjugation of these mcr genes conferred a colistin resistance phenotype upon the recipient bacterium.PCR typing of plasmids harbored in the 25 transconjugants determined six types of plasmid replicons,including lncX4(14/25),FrepB(4/25),Incl2(3/25),lncHI2(2/25),FIB(1/25),and Inch(1/25).This study contributes to the current understanding of antibiotic resistance and molecular characteristics of colistin-resistant£coli in pig farms.

Development of A Super-Sensitive Diagnostic Method for African Swine Fever Using CRISPR Techniques

African swine fever(ASF)is an infectious disease caused by African swine fever virus(ASFV)with clinical symptoms of high fever,hemorrhages and high mortality rate,posing a threat to the global swine industry and food security.Quarantine and control of ASFV is crucial for preventing swine industry from ASFV infection.In this study,a recombinase polymerase amplification(RPA)-CRISPR-based nucleic acid detection method was developed for diagnosing ASF.As a highly sensitive method,RPA-CRISPR can detect even a single copy of ASFV plasmid and genomic DNA by determining fluorescence signal induced by collateral cleavage of CRISPR-lw Cas13 a(previously known as C2c2)through quantitative real-time PCR(q PCR)and has the same or even higher sensitivity than the traditional q PCR method.A lateral flow strip was developed and used in combination with RPA-CRISPR for ASFV detection with the same level of sensitivity of Taq Man q PCR.Likewise,RPA-CRISPR is capable of distinguishing ASFV genomic DNA from viral DNA/RNA of other porcine viruses without any cross-reactivity.This diagnostic method is also available for diagnosing ASFV clinical DNA samples with coincidence rate of 100%for both ASFV positive and negative samples.RPA-CRISPR has great potential for clinical quarantine of ASFV in swine industry and food security.

Two Inhibitors Against the 3C-Like Proteases of Swine Coronavirus and Feline Coronavirus

Coronaviruses(CoVs)are important human and animal pathogens that cause respiratory and gastrointestinal diseases.Porcine epidemic diarrhoea(PED),characterized by severe diarrhoea and vomiting in pigs,is a highly lethal disease caused by porcine epidemic diarrhoea virus(PEDV)and causes substantial losses in the swine industry worldwide.However,currently available commercial drugs have not shown great therapeutic effects.In this study,a fluorescence resonance energy transfer(FRET)-based assay was applied to screen a library containing 1,590 compounds and identified two compounds,3-(aminocarbonyl)-1-phenylpyridinium and 2,3-dichloronaphthoquinone,that target the 3C-like protease(3CL^(pro))of PEDV.These compounds are of low molecular weight(MW)and greatly inhibited the activity of this enzyme(IC_(50) values were obtained in this study).Furthermore,these compounds exhibited antiviral capacity against another member of the CoV family,feline infectious peritonitis virus(FIPV).Here,the inhibitory effects of these compounds against CoVs on Vero cells and feline kidney cells were identified(with EC_(50) values)and cell viability assays were performed.The results of putative molecular docking models indicate that these compounds,labeled compound 1 and compound 2,contact the conserved active sites(Cys144,Glu165,Gln191)of 3CL^(pro) via hydrogen bonds.These findings provide insight into the antiviral activities of compounds 1 and 2 that may facilitate future research on anti-CoV drugs.

Phospho-proteomics identifies a critical role of ATF2 in pseudorabies virus replication

Pseudorabies virus(PRV),an etiological agent of pseudorabies in livestock,has negatively affected the porcine industry all over the world.Epithelial cells are reported as the first site of PRV infection.However,the role of host proteins and its related signaling pathways in PRV replication is largely unclear.In this study,we performed a quantitative phosphoproteomics screening on PRV-infected porcine kidney(PK-15)epithelial cells.Totally 5723phosphopeptides,corresponding to 2180 proteins,were obtained,and the phosphorylated states of 810 proteins were significantly different in PRV-infected cells compared with mock-infected cells(P<0.05).GO and KEGG analysis revealed that these differentially expressed phosphorylated proteins were predominantly related to RNA transport and MAPK signaling pathways.Further functional studies of NF-κB,transcription activator factor-2(ATF2),MAX and SOS genes in MAPK signaling pathway were analyzed using RNA interference(RNAi)knockdown.It showed that only ATF2-knockdown reduces both PRV titer and viral genome copy number.JNK pathway inhibition and CRISPR/Cas9 gene knockout showed that ATF2 was required for the effective replication of PRV,especially during the biogenesis of viral genome DNA.Subsequently,by overexpression of the ATF2 gene and point mutation of the amino acid positions 69/71 of ATF2,it was further demonstrated that the phosphorylation of ATF2 promoted PRV replication.These findings suggest that ATF2 may provide potential therapeutic target for inhibiting PRV infection.

Screening of novel synthetic derivatives of dehydroepiandrosterone for antivirals against flaviviruses infections

Flaviviruses are important arthropod-borne pathogens that represent an immense global health problem.Their unprecedented epidemic rate and unpredictable clinical features underscore an urgent need for antiviral interventions.Dehydroepiandrosterone(DHEA)is a natural occurring adrenal-derived steroid in the human body that has been associated in protection against various infections.In the present study,the plaque assay based primary screening was conducted on 32 synthetic derivatives of DHEA against Japanese encephalitis virus(JEV)to identify potent anti-flaviviral compounds.Based on primary screening,HAAS-AV3026 and HAAS-AV3027 were selected as hits from DHEA derivatives that exhibited strong antiviral activity against JEV(IC_(50)=2.13 and 1.98μmol/L,respectively)and Zika virus(ZIKV)(IC_(50)=3.73 and 3.42μmol/L,respectively).Mechanism study indicates that HAAS-AV3026 and HAAS-AV3027 do not exhibit inhibitory effect on flavivirus binding and entry process,while significantly inhibit flavivirus infection at the replication stage.Moreover,indirect immunofluorescence assay,Western blot analyses,and quantitative reverse transcription-PCR(qRT-PCR)revealed a potent antiviral activity of DHEA derivatives hits against JEV and ZIKV in terms of inhibition of viral infection,protein production,and viral RNA synthesis in Vero cells.Taken together,our results may provide a basis for the development of new antivirals against flaviviruses.

Japanese Encephalitis Virus NS1' Protein Antagonizes Interferon Beta Production

Japanese encephalitis virus(JEV) is a mosquito-borne virus and the major cause of viral encephalitis in Asia. NS1', a52-amino acid C-terminal extension of NS1, is generated with a-1 programmed ribosomal frameshift and is only present in members of the Japanese encephalitis serogroup of flaviviruses. Previous studies demonstrated that NS1' plays a vital role in virulence, but the mechanism is unclear. In this study, an NS1' defected(rG66A) virus was generated. We found that rG66A virus was less virulent than its parent virus(pSA14) in wild-type mice. However, similar mortality caused by the two viruses was observed in an IFNAR knockout mouse model. Moreover, we found that rG66A virus induced a greater type Ⅰ interferon(IFN) response than that by pSA14, and JEV NS1' significantly inhibited the production of IFN-b and IFN-stimulated genes. Taken together, our results reveal that NS1' plays a vital role in blocking type I IFN production to help JEV evade antiviral immunity and benefit viral replication.

Highly Efficient Base Editing in Viral Genome Based on Bacterial Artificial Chromosome Using a Cas9-Cytidine Deaminase Fused Protein

Viruses evolve rapidly and continuously threaten animal health and economy,posing a great demand for rapid and efficient genome editing technologies to study virulence mechanism and develop effective vaccine.We present a highly efficient viral genome manipulation method using CRISPR-guided cytidine deaminase.We cloned pseudorabies virus genome into bacterial artificial chromosome,and used CRISPR-guided cytidine deaminase to directly convert cytidine(C)to uridine(U)to induce premature stop mutagenesis in viral genes.The editing efficiencies were 100%.Comprehensive bioinformatic analysis revealed that a large number of editable sites exist in pseudorabies virus(PRV)genomes.Notably,in our study viral genome exists as a plasmid in E.coli,suggesting that this method is virus species-independent.This application of base-editing provided an alternative approach to generate mutant virus and might accelerate study on virulence and vaccine development.

Reprogramming Mycobacterium tuberculosis CRISPR System for Gene Editing and Genomewide RNA Interference Screening

Mycobacterium tuberculosis is the causative agent of tuberculosis(TB), which is still the leading cause of mortality from a single infectious disease worldwide. The development of novel anti-TB drugs and vaccines is severely hampered by the complicated and time-consuming genetic manipulation techniques for M. tuberculosis. Here, we harnessed an endogenous type Ⅲ-A CRISPR/Cas10 system of M. tuberculosis for efficient gene editing and RNA interference(RNAi).This simple and easy method only needs to transform a single mini-CRISPR array plasmid, thus avoiding the introduction of exogenous protein and minimizing proteotoxicity. We demonstrated that M. tuberculosis genes can be efficiently and specifically knocked in/out by this system as confirmed by DNA high-throughput sequencing. This system was further applied to single-and multiple-gene RNAi. Moreover, we successfully performed genome-wide RNAi screening to identify M. tuberculosis genes regulating in vitro and intracellular growth. This system can be extensively used for exploring the functional genomics of M. tuberculosis and facilitate the development of novel anti-TB drugs and vaccines.

Cholesterol-25-Hydroxylase Suppresses Seneca Valley Virus Infection via Producing 25-Hydroxycholesterol to Block Adsorption Procedure

Cholesterol-25-hydroxylase(CH25 H)is a membrane protein associated with endoplasmic reticulum,and it is an interferon-stimulated factor regulated by interferon.CH25 H catalyzes cholesterol to produce 25-hydroxycholesterol(25 HC)by adding a second hydroxyl to the 25 th carbon atom of cholesterol.Recent studies have shown that both CH25 H and 25 HC could inhibit the replication of many viruses.In this study,we found that ectopic expression of CH25 H in HEK-293 T and BHK-21 cell lines could inhibit the replication of Seneca Valley virus(SVV)and that there was no species difference.On the other hand,the knockdown of CH25 H could enhance the replication of SVV in HEK-293 T and BHK-21 cells,indicating the importance of CH25 H.To some extent,the CH25 H mutant without hydroxylase activity also lost its ability to inhibit SVV amplification.Further studies demonstrated that 25 HC was involved in the entire life cycle of SVV,especially in repressing its adsorption process.This study reveals that CH25 H exerts the advantage of innate immunity mainly by producing 25 HC to block virion adsorption.