A Cross-sectional study on tick-borne Rickettsiae infections among murine-like animals / 预防医学

Objective Toinvestigatethestatusoftick-borneRickettsiaeinfectionsamongmurine-likeanimalsin differentareasofZhejiangprovince.Methods Liverandspleensamplesofmurine-likeanimalscapturedthroughnight trapping method were collected from Anji,Jinhua and Tiantai County according to their geographic locations and historical detection of Rickettsiae .Nest-PCR tests were used to determine the presence of the 16S rRNA genes of Anaplasma and Ehrlichia ,and the heat shock protein genes (groEL)of Rickettsiae (including typhus and spotted fever group)and Orientiainthesesamples.Results Atotalof851murine-likeanimalsbelongingto14specieswerecaptured.The predominant species were Rattus confucianus (30.32%),Apodemus agrarius (18.80%) and Thallomys paedulcus (1 1.75%)and they were significantly different among three areas (P<0.05 ).48 Rickettsia positive were found in 562 tested samples with the positive rate of 8.54%,among which the percentage of Anaplasma,typhus group Rickettsia, Orientia,Ehrlichia and spotted fever group Rickettsia were 3.38%,1.78%,1.78%,1.07% and 0.53% respectively. The positive rates of Anaplasma in Jindong (4.76%)and Anji (4.27%)were significantly higher than that in Tiantai (P<0.05 )while the spotted fever group Rickettsia were found only in Tiantai County.Moreover,Rattus confucianus-the predominant species of Zhejiang Province-had the highest infection rate of tick-borne Rickettsiae up to 14.97%.Co-infections with several Rickettsiae were existed among the same species.Conclusion Rickettsiae infections exist widely among different areas of Zhejiang province and the positive rates are significantly different among species.

Sero-epidemiologic investigation on tick-borne diseases of humans and domestic animals in Zhejiang province / 中华流行病学杂志

Objective To investigate the seroprevalence of tick-borne diseases in humans and domestic animals from rural areas of Zhejiang province. Methods Anji county, Jindong district and Tiantai county were selected for samples collection according to their geographic locations and historical prevalence of tick-borne diseases. Blood samples of humans and domestic animals were collected in the three sites. An indirect immuno-fluorescent antibody test was used to determine the presence of IgG antibodies of Rickettsiae heilongjiangii, Orientia tsutsugamushi, R. typhi, Anaplasma phagocytos, Ehrlichia chaffeensis, Bartonella, R. hainan and Coxiella burnetii in these samples.Results Six hundred and eighty-three blood samples including 579 from humans and 104 from domestic animals(53 from cattles and 51 from sheep)were collected from the three sites. Antibody positive rates of Orientia tsutsugamushi, R. typhi, Ehrlichia chaffeensis and Coxiella burnetii were significantly different between these sites. IgG from all the 8 pathogens were detected in samples from humans. It was found that the sero-prevalence rates of R. typhi, Bartonella and C. burnetii(20.7%,10.9%, 5.5%)of adults were higher than those of other Rickettsiae under investigation. The seroprevalence of R. typhi increased along with age. IgG from the 7 pathogens were detected in samples from domestic animals except for Anaplasma phagocytos. The sero-prevalence rates of R. typhi, Bartonella and R. hainan(69.2%, 51.0%, 22.1%)of adults were higher than those of other Rickettsiae investigated. Conclusion Tick-borne diseases did spread widely in humans and domestic animals from different rural areas of Zhejiang province. The sero-prevalence rates of R. typhi,B. henselae, R. hainan and C. burnetii were higher than that from other pathogens.

Detection of enterohemorrhagic Escherichia coli O157:H7 by loop-mediated isothermal amplification / 中华预防医学杂志

<p><b>OBJECTIVE</b>To develop a loop-mediated isothermal amplification (LAMP) method for rapidly diagnosing of Escherichia coli (EHEC) O157:H7 in pathogen detection department or small-scale laboratories.</p><p><b>METHODS</b>Primers for LAMP test were designed by targeting the antigen coding rfbE of EHEC O157:H7, the Shiga-like toxin stx2 and the fliC encoding gene of H7 flagella antigen, respectively. The reaction condition and reaction system of LAMP were optimized. 2 EHEC O157:H7 type strains, 17 local strains and 33 other enterobacteria were analyzed to evaluate the LAMP's specificity and sensitivity. The results of the LAMP reaction were also compared with routine PCR method.</p><p><b>RESULTS</b>The amplification products of O157 which had the corresponding target genes turned green by visual inspection and had ladder-like pattern on the gel, but products of other enterobacteria remained orange by visual examination and had no band on the gel. The detection results of LAMP were the same as of routine PCR method. The reaction time of the LAMP method was only 1.5 hours and the detection limit of LAMP assay was 26 CFU/reaction. In addition, the LAMP results could be determined only by visual inspection.</p><p><b>CONCLUSION</b>LAMP assay is rapid, specific, and sensitive for the detection of EHEC O157:H7. This method might not only reduce the dependence of complicated equipments but also be a potential method for wider use in pathogen detection department, small-scale laboratory, emergency motor vehicle or field survey.</p>

Detection of co-infection with Lyme spirochetes and Spotted fever group rickettsiae in a group of Haemaphysalis longicornis / 中华流行病学杂志

Objective The present study was conducted to investigate the infection of Lyme disease, Spotted fever, Ehrlichiosis (anaplasmosisin) in wild animals and ticks in the mountain areas of Zhejiang province. Methods Nested polymerase chain reaction was used to amplify specific DNA sequences of Lyme spirochetes, Spotted fever group rickettsiae, Ehrlichia (anaplasma) from samples of mice and ticks. Results 14 positive samples were identified from 121 mice and 105 groups of ticks. Among mice samples, one positive 5S-23S rDNA intergenic spacer of Borreia burgdorferi and two 5' fragments of Ehrlichia (anaplasma) 16S rDNA were obtained. 11 positive results were detected from tick samples including three 5S-23S rDNA intergenic spacer regions of Borreia burgdorferi and eight 5' fragments of Spotted fever group rickettsiae outer member protein A gene. One group of adult ticks, Haemaphysalis longicornis, which had been collected from eastern mountain area were detected to have co-infected with Lyme spirochetes and Spotted fever group rickettsiae. The positive sequences of 5S-23S rDNA intergenic spacer and ompA gene were tested and analyzed as Lyme spirochetes while rickettsia which was closely related to Borrelia valaisiana and R. massilliae. Conclusion This was the first report about co-infection of Lyme spirochetes and Spotted fever group rickettsiae found in the same group of adult Haemaphysalis longicornis. It is very important to strengthen the surveillance program on tick-borne infectious disease and their pathogenic in vectors, wild animals and targeted high risk groups and to differentiate the clinical manifestation and diagnosis to extend the knowledge of tick-borne infectious diseases in Zhejiang.

Molecular characterization and sequence comparison of the M and S segments of Hantavirus ZJ5 strain / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>In order to understand the molecular characters of Hantavirus ZJ5 strain, its complete M and S genome were sequenced and compared with that of other hantavirus strains.</p><p><b>METHODS</b>We prepared the total RNA from ZJ5. Infected cells and the raw or purified RT-PCR product was cloned and sequenced.</p><p><b>RESULTS</b>With sequence compation, we found ZJ5 strain complete M and S segment had higher homology with SEO-type strains than other type of HV, but differential genes were 11.7%-19.2% and 6.7%-14.5% from SEOV. The phylogenetic trees constructed by complete M ind S segment showed that ZJ5 strain was located in SEOV group, and structured alone embranchment.</p><p><b>CONCLUSION</b>The ZJ5 strain was believed to belong to SEO-type virus,and suggest that ZJ5 strain is a new subtype S SEOV group,and structured alone embranchment.</p><p><b>CONCLUSION</b>The ZJ5 strain was believed to belong to SEO-type virus, and suggest that ZJ5 strain is a new subtype from other SEO viruses.</p>

Study on the recombinant expression of Hantaan virus protein N and the establishment and application of rNP-IgM direct capture ELISA / 中华流行病学杂志

<p><b>OBJECTIVE</b>To clone the gene encoding nucleocapsid protein (NP) of hantavirus strain Z10 (HV-Z10), to construct its prokaryotic expression system as well as to establish a rNP-IgM direct capture ELISA based on HRP-labeled recombinant NP (rNP), in order to detect serum samples of patients suffering from hemorrhagic fever with renal syndrome (HFRS) and to evaluate the effects of detection.</p><p><b>METHODS</b>Gene encoding NP of strain HV-Z10 was amplified by PCR and then its prokaryotic expression system pET28a-Z10N-E. coli BL21DE3 was constructed, using routine genetic engineering method. SDS-PAGE was applied to measure the expression of rNP and ion-exchange plus Ni-NTA-affinity chromatography was performed to purify the recombinant product. Western blot assay was used to determine the specific immuno-reactivity of rNP while HRP-labeled rNP-IgM direct capture ELISA was established to detect the serum samples from 95 cases of confirmed HFRS patients. The detection effect was compared with that by routine HV-IgM indirect capture ELISA method.</p><p><b>RESULTS</b>pET28a-Z10N-E. coli BL21DE3 was able to express rNP with high efficiency. The purified rNP only showed a single protein fragment in the gel after SDS-PAGE. HV-IgG could efficiently recognize rNP and hybridize with the recombinant protein. 94.73% (90/95) of HFRS patients' serum samples were positively confirmed by rNP-IgM direct capture ELISA, while a positive rate of 92.63% (88/95) in the same samples was confirmed by HV-IgM indirect capture ELISA. The distributions of A450 values of the serum samples detected by the two IgM capture ELISAs as well as the changes of the A450 mean values from several serum samples with different dilutions were similar.</p><p><b>CONCLUSION</b>We successfully constructed a high efficient prokaryotic expression system of NP encoding gene of hantavirus strain HV-Z10. The rNP-IgM direct capture ELISA that established in this study could be used as a new serological test for HFRS diagnosis because of its simplicity, safety, with high sensitivity and specificity.</p>