Scrub typhus is a type of natural focal disease caused by a bacteria called Orientia tsutsugamushi and mainly en-demic in East and Southeast Asia.The most common clinical symptoms of scrub typhus include fever,eschar,ulcer,lymph node enlargement and rash,which are not typical on early stage and could easily lead to misdiagnosis and missed diagnosis.By reviewing relevant guidelines and references at home and abroad,combining clinical diagnosis and treatment experiences in Chi-na,the experts from Biodiagnostic Technology Branch of China Medical Biotechnology Association and Chinese Society of Mi-crobiology Committee on Zoonotic Pathogens formed this consensus on the clinical diagnosis and treatment of scrub typhus.

According to the codon characteristics of the prokaryotic system,we synthesized the optimized Rv2628c-Rv1737c nucleic acid sequence and constructed the expression plasmid pET24a-Rv2628c-Rv1737c.After sequencing,expression in E.coli was induced.The fusion protein was found in inclusion bodies.After renaturation and affinity chromatography purifi-cation,the Rv2628c-Rv1737c recombinant protein,with a molecular weight of 57 kDa and a purity exceeding 90％,was ob-tained.The recombinant protein was used to stimulate PBMC cells from different patients,and the differences in IFN-γ mRNA expression were analyzed with q-PCR.The Rv2628c-Rv1737c fusion protein stimulated patients with TB,particularly latent TB infection(LTBI).The level of IFN-γ mRNA in PBMC cells was higher than that in healthy controls(P＜0.05).Mice immu-nized with BCG+Rv2628c-Rv1737c/DMT showed significant induction of high levels of IgG antibodies.Rv2628c-Rv1737c re-combinant protein,as a latent infection antigen,is recognized by PBMCs cells infected with TB,with strong immunogenicity,and thus may serve as a potential TB subunit vaccine target antigen.This protein may be used to prevent TB infection,particu-larly latent infection,and to perform laboratory diagnosis.

To characterize human antibodies against low-calcium response V(LcrV)antigen of Yersinia pestis,the mono-clonal antibodies were screened and assayed.Antibody gene was derived from peripheral blood mononuclear cells of the vaccin-ees immunized by plague subunit vaccine in phase Ⅱb clinical trial.Human ScFv antibody library was constructed by phage dis-play.After panning library by using recombinant LcrV antigen,antibody variable genes were sequenced and converted into IgG1 format to evaluate its binding specificity and relevant parameters.An anti-plague human ScFv antibody library was estab-lished contained 7.54× 108 independent clones.After panning by LcrV antigen,3 human antibodies named as RV-B4,RV-D1 and RV-E8,respectively,were identified.Using indirect enzyme-linked immunosorbent assay(ELISA)and Western blot(WB),the specific bindings of the mAbs to LcrV antigen were confirmed.The dissociation constant(KD)of them to LcrV is 2.1 nmol/L,1.24 nmol/L and 42 nmol/L,respectively.Minor protective efficacy was found among 3 human antibodies in Y.pestis 141-infected mice.Three anti-LcrV monoclonal antibodies generated from immunized vaccinees were binding specific antibod-ies and could not block plague infection in mice.These antibodies are the potential candidate reagents for basic research of plague immunity and the application of plague diagnosis.

The growth of three plague phages from Qinghai Plateau in two Yersinia pestis strains(plague vaccine strains EV76 and 614F)and four non-Yersinia pestis strains(Yersinia pseudotuberculosis PTB3,PTB5,Escherichia coli V517,and Yersinia enterocolitica 52302-2)were detected through a micromethod based on the OmniLogTM microbial identification system and by the drop method,to provide a scientific basis for future ecological studies and classification based on the host range.For plague vaccine strains EV76 and 614F,successful phage infection and subsequent phage growth were observed in the host bacte-rium.Diminished bacterial growth and respiration and a concomitant decrease in color were observed with the OmniLogTM mi-crobial identification system at 33 ℃ for 48 h.Yersinia pseudotuberculosis PTB5 was sensitive to Yersinia pestis phage 476,but Yersinia pseudotuberculosis PST5 was insensitive to phage 087 and 072204.Three strains of non-Yersinia pestis(Yersinia pseudotuberculosis PTB3,Escherichia coli V517,and Yersinia enterocolitica 52302-2)were insensitive to Yersinia pestis pha-ges 087,072204,and 476 showed similar growth curves.The growth of phages 476 and 087,as determined with the drop method,in two Yersinia pestis strains(plague vaccine strains EV76 and 614F)and four non-Yersinia pestis strains(Yersinia pseudotuberculosis PTB3,Escherichia coli V517,and Yersin-ia enterocolitica 52302-2)showed the same results at 37 ℃,on the basis of comparisons with the OmniLogTM microbial i-dentification system;in contrast,phages 072204 did not show plaques on solid medium at 37 ℃ with plague vaccine strains EV76 and 614F.Determination based on the OmniLogTM detection system can be used as an alternative to the traditional determination of the host range,thus providing favorable application val-ue for determining the interaction between the phage and host bacteria.

The ICR(Institute of Cancer Research)mouse infection model was constructed to study the pathogenicity of Sal-monella Telelkebir serotype,and the pathogenic identification of mouse isolates was carried out.Observe the bacterial excretion cycle,evaluate the pathogenicity of Salmonella serotype to mice,and calculate the LD50 by the changes in clinical characteris-tics,histopathology and tissue bacterial load of infected mice;by flight mass spectrometry,biochemical identification,serotype identification,molecular typing and other experiments,compared with human isolates;virulence gene analysis was carried out by PCR experiment and whole genome sequencing.The LD50 of Salmonella Telelkebir is 2.67 × 108 CFU/mL;curling and fluffing may occur 0.5 h after infection;autopsy of dead mice showed that the small intestine was severely congested,with more bubbles and fluid accumulation,cecal necrosis,liver apical degeneration and necrosis,necrotic foci on the surface of the kidney and spleen atrophy;the bacterial load of spleen,kidney,lung,liver and jejunum in mice reached its peak at 3 days after infection,while that of heart at 6 days;the bacterial excretion time of the high-dose group exceeded 100 days;The level of CD3 in tissues increased with increasing dose,with inflammatory cell infiltration,myocardial capillary dilation and hyperemia,large area of vacuoles,degeneration and necrosis of hepatocytes,obvious enlargement of splenic sinus,blurred zoning,thickening of glomerular basement membrane,partial exfoliation of ciliated epithelium,atrophy and exfoliation of jejunal villi;PCR and whole genome sequencing revealed Salmonella-related virulence genes such as cdtB,plt A and pltB.This study was the first to successfully establish the ICR mouse model of Salmonella Telelkebir,demonstrating that this serotype of Salmonella has some pathogenicity.

The aim of this study was to investigate the virulence determinants and genetic diversity of foodborne Yersinia enterocolitica from Wenzhou.A total of 71 strains of Yersinia enterocolitica were isolated from food and foodborne diarrhea ca-ses in Wenzhou,and their biotypes,serotypes,and drug resistance were analyzed.On the basis of whole genome sequencing,we assessed virulence gene profiles,and performed multilocus sequence typing(MLST)and core gene multilocus sequence typ-ing(cgMLST).A total of 94.4％(67/71)of isolates belonged to biotype 1A,and the highest proportion had serotype lA/O∶5(29.6％,21/71).The sensitivity rates of the isolates to 14 antibiotics exceeded 95.8％.A total of 16 categories and 126 viru-lence genes were identified,with two strains carrying the pYV plasmid and chromosome-related virulence genes.ST3(31.6％,12/38)was the most widespread MLST type,and cgMLST analysis revealed no dense clusters of genotypes except for strains sharing the same ST.In conclusion,pathogenic strains were identified from foodborne Yersinia enterocolitica in Wenzhou and were found to exhibit high genetic polymorphism.Enhanced regulatory supervision is essential to prevent the outbreak of food-borne diseases caused by Yersinia enterocolitica.

To understand Helicobacter pylori's drug resistance,genetic diversity,and relationship with clinical diseases in the Guiyang and Qiannan minority areas of Guizhou Province,we collected samples through endoscopy,and isolated and cul-tured H.pylori.The drug resistance and genotype characteristics were determined.The differences in different regions and dis-ease types were compared,and the structural characteristics of H.pylori and mixed infections with different strains of H.py-lori in Qiannan Prefecture were analyzed.A difference in the composition ratio of EPYIA typing in the cagA variable region was observed between the two areas(P=0.012),and the composition ratio of the vacA genotype differed(P=0.000).A total of 94.6％(53/56)new sequences of H.pylori strains from two regions were obtained by MLST.The rate of infection by H.pylori mixed with different strains was 44.4％in Qiannan Pre-fecture,and no significant difference was observed in the com-position of H.pylori mixed infections among patients with dif-ferent clinical diseases(P=0.349).Differences in EPI YA typ-ing and the vacA genotype composition ratio in the cagA varia-ble region of H.pylori were observed between the Qiannan Prefecture and Guiyang City.

This study was aimed at analyzing the molecular characteristics of enteropathogenic Escherichia coli(E.coli)strains isolated from domestic animals at a surveillance site in Jiangsu province and evaluating their potential pathogenicity,to provide evidence supporting the surveillance,prevention,and control of infectious diarrhea.Thirty-seven EPEC strains isolated from domestic animals at this surveillance site were characterized by whole genome sequencing.All EPEC strains isolated from local livestock were aEPEC,which has a variety of serotypes and carries a variety of virulence genes associated with diarrhea.Nine ST types with regional epidemic characteristics were identified.Five eae gene subtypes were found,among which β1 was dominant and was also the most common strain in patients with diarrhea.According to analysis of the characteristics of 37 EPEC strains,all EPEC strains from local livestock were aEPEC,thus posing a potential threat to public health.Monitoring of livestock feces and the breeding environment must be strengthened in the surveillance of infectious diarrhea.

Lyme disease is a natural zoonotic infectious disease transmitted by ticks infected by different genotypes of Borre-lia burgdorferi sensu lato,which was discovered in the 1970s.This pathogen is prevalent primarily in temperate and subtropi-cal areas.Dogs,cats,horses,cattle,deer,and other animals are susceptible,and humans are also susceptible hosts.The main symptoms of Lyme disease in humans are erythema migrans,arthritis,and other neurological symptoms,and the common symptoms in infected animals include joint diseases,coat shedding,fever,laminitis,and lameness.Lyme disease is wide-spread,but diagnosis is difficult,and this disease is easily misdiagnosed and missed.Awareness of Lyme disease must be in-creased to avoid its toll on livestock and the pet industry.Therefore,this article reviews research progress in diagnosis and con-trol technology for animal Lyme disease and Borrelia burgdorferi,to provide a reference for accurate,rapid diagnosis and con-trol of Lyme disease.

Trichinosis is a global food-borne zoonotic parasitic disease caused by Trichinella spiralis(T.spiralis),which causes serious harm to animal production,and the public health safety of humans and animals.T.spiralis has a complex devel-opment history,and its entire life cycle is completed in the same host.To coexist with the host,it has evolved various immune escape mechanisms for avoiding immune clearance by the host,thus establishing long-term chronic infection.In this study,to aid in understanding the pathogenic mechanism of T.spiralis,the immune escape mechanism of Trichinella is discussed from three aspects:the molecular role of antigens in various stages,the immune regulatory effect on the host,and the formation of cysts to generate immune isolation.