Flagella Phenotypic Variations of ST34 Type Salmonella Typhimurium and Variants.

Salmonella enterica serovar Typhimurium and its variants are the most common serotypes of human salmonellosis cases. Serotyping Salmonella Typhimurium and its variants has always been challenging. Our previous work found that among 14 Salmonella Typhimurium and variant strains, some different antigenic formulas had 100% pulsed-field gel electrophoresis (PFGE) similarity. The 14 strains were sorted into 3 groups; in each group, the different antigenic formulas had the same PFGE patterns. This phenomenon suggested that different antigenic formula identification might originate from a common ancestor subtyped by PFGE. To assess whether the serotyping method on Salmonella Typhimurium and variant strains reflected the genetic relationship, we improved the discrimination for the phylogenetic relationship among the 14 Salmonella Typhimurium and variant strains using Fourier-transform infrared spectroscopy (FTIR) and whole-genome multilocus sequence typing (wgMLST). We compared the wgMLST assay of 14 Salmonella Typhimurium and variant strains from this study with 50 public ST34 strain data of Salmonella Typhimurium and variant strains. We also compared flagella (H antigen)-related genes based on the whole genome of 14 strains and the other 293 ST34 public database for further understanding of this question. The phylogenetic results (PFGE) showed no regularity between the antigenic formulas and genotypes. The results of the higher discrimination power assays (FTIR and whole-genome multilocus sequence typing) also showed no regularity between the antigenic formulas and genotypes (or phenotypes). The 58 flagella encoding genes of different antigenic formulas were sorted into 13 patterns. However, a similar phenomenon was found: the same flagella encoding gene patterns could express different antigenic formulas. In conclusion, there is no consistency between the antigenic formulas and phylogenetic relationships among ST34 Salmonella Typhimurium and variant strains, even in flagella antigenic formula and flagella encoding genes.

[Construction, Identification, and Expression of Lactococcus lactis-Based Recombinant Vaccine for Echinococcus granulosus]. / ä¹³é ¸ä¹³çƒèŒä»‹å¯¼çš„ç»†ç²’æ£˜çƒç»¦è™«é‡ç»„LL-Eg95疫苗的构建、鉴定及表达.

Objective: To construct Lactococcus lactis (LL)-based recombinant LL-Eg95 (rLL-Eg95) vaccine for Echinococcus granulosus (Eg) and to examine its expression efficiency. Methods: Eg95 gene was obtained by PCR from the template of pCD-Eg95. Then, pMG36e was inserted in the Eg95 gene after double cleaving with restriction endonucleases XbaⅠ and HindⅢ to construct recombinant plasmid pMG36e-Eg95, which was transformed into E.coli BL2 (DE3) competent cells. The recombinant plasmid was extracted and identified by double restriction endonuclease digestion and was then electroporated into LL MG1363 to construct rLL-Eg95 vaccine. Then, the plamid was extracted and identified by PCR. Results: Examination of the recombinant plasmid by double restriction endonuclease digestion showed that the segment was of the expected length. PCR showed that 471 base pairs of Eg95 gene were amplified when the plasmid extracted from roxithromycin-resistant recombinant LL was used as the template. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that the relative molecular mass of the Eg95 protein expressed was approximately 16.5×103 and that the amount of the expressed protein was 17% of the total bacterial proteins. Western blot findings suggested that the expressed protein could be recognized by mice serum infected with hydatid cyst. Conclusion: The rLL-Eg95 vaccine was successfully constructed, expressing Eg95 protein that has specific antigenicity.

Correlation analysis of epicardial adipose tissue volume quantified by computed tomography images and coronary heart disease under optimized reconstruction algorithm.

OBJECTIVES: This paper was aimed to explore the adoption value of low-dose computed tomography (CT) imaging based on optimized ordered subset expectation maximization (OSEM) reconstruction algorithm in the correlation analysis between epicardial adipose tissue (EAT) volume and coronary heart disease (CHD). METHODS: A total of 110 patients with CHD were selected for CT angiography (CTA) and coronary arteriography (CAG) examinations from October 2017 to October 2019. The predictive value of EAT for CHD was analyzed via receiver operating characteristic (ROC) curve. RESULTS: The results showed that the iteration time and error of the improved OSEM reconstruction algorithm were better than that of MLEM algorithm under the same number of iterations. Age, smoking, hypertension, diabetes, and EAT in control group were obviously lower in contrast to those in CHD group (P<0.05). EAT in control group was (124.50±26.72) mL, and EAT in the CHD group was (159.41±38.51) mL. EAT (B=0.023, P=0.003) was an independent risk factor for CHD, which was suggested by Multiple linear regression analysis. Moreover, EAT was a risk factor for CHD, and was positively correlated with the degree and NSCV. CONCLUSION: The optimized OSEM algorithm was used to improve the reconstruction quality of low-dose CT images and used in quantitative measurement of epicardial fat volume. Results showed EAT was an independent risk factor for CHD, and was positively correlated with the number of coronary lesions and Gensini score. It was of great value for the prediction of CHD.

Effect of layer-distributed carbon nanotube (CNT) on mechanical and piezoresistive performance of intelligent cement-based sensor.

Agglomerated carbon nanotube (CNT) powder was scattered into a cement paste layer-by-layer to form layer-distributed CNT composite (LDCC) as intelligent cement-based sensor. The characteristic of the CNT agglomerations and its effect on the mechanical and piezoresistive properties of cement paste were investigated in this study, and the results were compared with those of uniformly-dispersed CNT composites (UDCC). Based on the statistics of CNT agglomerations, it was found that the sizes of agglomerations varied from several to dozens of micrometres. The larger sized agglomerations with poorer roundness exhibited a higher possibility to cause the pores or voids accompanied with stress concentration when subjected to external forces. Hence, it is necessary to control the agglomeration sizes to reduce the porosity with edges and corners. The UDCC reached the highest compressive strength, followed by the plain cement paste and then LDCC. The mechanical strength of LDCC decreased with the increase of CNT layers. The piezoresistivity occurred in both the UDCC and LDCC, with the former possessing stable and repeatable performance. In addition, the strain-sensing ability of LDCC with moderate CNT layers presented similar sensing efficiency and repeatability to that of UDCC. The related results provide insight into the intelligent cement-based sensors with layer-distributed CNT and agglomerations, which can improve the efficiency and effectively reduce the cost for practical application.

Molecular epidemiology and genetic variation analyses of porcine circovirus type 2 isolated from Yunnan Province in China from 2016-2019.

BACKGROUND: Porcine circovirus type 2 (PCV2) is the causative agent of porcine circovirus-associated disease (PCVAD). Its prevalence in swine herds was first reported in China in 2000. PCV2 infection causes immunosuppression that leads to multiple diseases, causing serious economic problems for the swine industry in China. Since information on the genetic variation of PCV2 in Yunnan province is limited, this study aims to investigate the molecular epidemiological and evolutionary characteristics of PCV2 from 2016 to 2019. METHODS: A total of 279 clinical samples were collected from different regions of Yunnan between 2016 to 2019, and PCV2 was detected by PCR. We then amplified full genomes from the positive samples, and the sequences were analysed for homology and genetic evolution. RESULTS: Overall, 60.93% (170/279) of the screened swine herd samples were positive for PCV2. We sequenced 15 Yunnan province PCV2 strains from positive samples. Analyses of the complete genomes and Cap genes led to the classification of the 15 Yunnan PCV2 strains into PCV2a (2 of 15), PCV2b (1of 15) and PCV2d (12 of 15). All strains shared 94.3-99.9% of their identities with the nucleotide sequences of complete genomes in this study and shared 94.2-99.9% identity with the reference sequences. All strains share 89.4-100% and 86.8-100% of their identities with the nucleotide and amino acid (aa) sequences of Cap, respectively. CONCLUSIONS: The results of this study provide evidence that PCV2a, PCV2b and PCV2d genotypes coexisted in Yunnan Province from 2016 to 2019, and the priority prevalence genotype was PCV2d. The data provide evidence for the increased genetic diversity and insights into the molecular epidemiology of PCV2. This study also provides basic data for the Yunnan province PCV2 molecular epidemiological survey and accumulates effective materials for the development of PCV2 vaccines.

[Study on Construction of Recombinant Bb-pGEX-OprI Vaccine of Pseudomonas aeruginosa and Its Protection Effect].

OBJECTIVE: To construct the recombinant Bb-pGEX-OprI vaccine of Pseudomonas aeruginosa (Pa) outer membrane protein I (OprI) and study its protection effect in mice against Pa. METHODS: The OprI gene was amplified by PCR,and cloned into pGEX-1λT to generate pGEX-OprI. The pGEX-OprI was transformed into Bifidobacterium bifidum(Bb) to construct recombinant Bb-pGEX-OprI vaccine by electroporation. After identification with double enzyme digestion,PCR and sequencing,the vaccine was then induced with IPTG,and its expression was analyzed and identified by SDS-PAGE and Western blot respectively. Twenty-one mice were randomly divided into 3 groups and vaccinated by intragastric administration with Bb-pGEX-OprI,Bb-pGEX-1λT and Bb respectively. All mice were challenged with PA01 strain at 4 weeks after the first vaccination. At 2 weeks after the challenge,mice were sacrificed to separate their lungs,and the numbers of bacterial colonies in lungs were counted. Venous blood was collected before vaccination,at 4 weeks after the first vaccination and 2 weeks after the challenge of PA01 strain. The serum IgG,IgG subclasses and IgE were detected by routine ELISA. RESULTS: The OprI gene of 194 bp was successfully amplified by PCR. Double enzyme digestion,PCR and sequencing confirmed that the OprI gene was successfully cloned into pGEX-1λT and pGEX-OprI was successfully transformed into Bb,constructing the Bb-pGEX-OprI vaccine. SDS-PAGE indicated that Bb-pGEX-OprI vaccine expressed an OprI-GST fusion protein with the relative molecular mass of approximately 32×103. Western blot verified that the fusion protein could be specifically identified by the sera of mice infected with Pa. The number of bacterial colonies in lung of Bb-pGEX-OprI vaccine group was lower than that of Bb-pGEX-1λT or Bb control ( P<0.01). The levels of serum IgG,IgG2b,IgG3 and IgE in Bb-pGEX-OprI vaccine group rose at 4 weeks after the first vaccination and 2 weeks after the challenge successively. The levels of serum antibodies in Bb-pGEX-OprI vaccine group were higher than those in Bb-pGEX-1λT or Bb control at the same time point ( P<0.01 or P<0.05). CONCLUSION: The recombinant Bb-pGEX-OprI vaccine was successfully constructed and produced an effective humoral immune response against the Pa infection.

Identification of Taeniothrips eucharii (Thysanoptera: Thripidae) as a Vector of Hippeastrum chlorotic ringspot virus in Southern China.

Hippeastrum chlorotic ringspot virus (HCRV) is a putative new member of the genus Tospovirus, which was first identified infecting Hymenocallis littoralis in Yunnan Province, southwestern China. Taeniothrips eucharii, the dominant thrips species found on H. littoralis, was tested for its efficiency as a vector of the virus. We used Western blot analysis of adult thrips to detect the N protein. Transmission experiments demonstrated an average acquisition efficiency of 43.7 ± 3.4% (AAP = 24 h) for the first larval stage and a transmission efficiency of 19.1 ± 2.4% (IAP = 24 h) for adult thrips. This study reports T. eucharii as a new genus and species of thrips transmitting a Tospovirus, HCRV.

Inhibition of porcine reproductive and respiratory syndrome virus replication in vitro using DNA-based short antisense oligonucleotides.

BACKGROUND: Porcine reproductive and respiratory syndrome (PRRS) is caused by porcine reproductive and respiratory syndrome virus (PRRSV) and is an economically important disease in swine-producing areas. The objective of this study was to screen for effective antisense oligonucleotides (AS-ONs) which could inhibit PRRSV replication in MARC-145 cells and in pulmonary alveolar macrophages (PAM). RESULTS: Nine short AS-ON sequences against the well-conserved regions of PRRSV (5'-UTR, NSP9, ORF5 and ORF7) were selected. When MARC-145 cells or PAM were infected with PRRSV followed by transfection with AS-ONs, four AS-ON sequences targeting 5'-UTR, ORF5 or NSP9 were found to be the most effective oligonucleotides in decreasing the cytopathic effect (CPE) induced by PRRSV infection. Quantitative PCR and indirect immunofluorescence staining confirmed that ORF7 levels were significantly reduced both at RNA and protein levels. The PRRSV titration data furthermore indicated that transfection with AS-ON YN8 could reduce the PRRSV titer by 1000-fold compared with controls. CONCLUSION: The results presented here indicate that DNA-based antisense oligonucleotides can effectively inhibit PRRSV replication in MARC-145 cells and in PAM. Furthermore, comparing with the reported hit rates (approximately 10-30 %), we achieved a higher success rate (44 %). The strategy we took to design the antisense sequences might be applied to select AS-ONs that more efficiently reduce the expression of target genes.

Genetic heterogeneity of swine hepatitis E virus isolates from Yunnan province, China in 2011-2012.

BACKGROUND: Hepatitis E is a disease of major public-health concern mainly in developing countries. Although molecular and sero-epidemiological investigations of HEV have been performed in many provinces in China, the epidemiological data from Yunnan Province are limited and genotypes are not be fully characterized. In this study the prevalence and characteristics of hepatitis E virus (HEV) detected in pigs from Yunnan province, China was evaluated. RESULTS: A total of 13 out of 187 pig fecal samples collected in 2011 revealed HEV positive results; likewise, 7 out of 69 samples collected in 2012 exhibited positive results. These findings indicated a total prevalence of 7.8% (20/256). Phylogenetic and molecular evolutionary analysis results revealed that nine strains were found in the samples obtained in 2011, in which 87.1% to 99.4% nucleotide sequence identity was shared among these strains; and 77.0% to 81.9%, 52.2% to 53.6%, 77.0% to 88.2% and 77.9% to 96.8% nucleotide sequence identities were shared with strains representing genotypes 1, 2, 3, and 4. Five strains were detected in the samples obtained in 2012, in which 94.2% to 99.3% nucleotide sequence identity was shared among the strains, and 81.0% to 82.5%, 81.8% to 83.2%, 81.0% to 92.7% and 81.0% to 97.8% nucleotide sequence identities were shared with strains representing the genotypes 1, 2, 3, and 4. CONCLUSIONS: Analysis of fourteen detected HEV strains revealed that three of them were subtype 4d, two were subtype 4b; the nine remaining isolated strains were subtype 4 h. These results indicated that the prevalence of HEV in the swine herds of Yunnan was quite high, additional public-health concerns should focus on pork safety.

Triaxial mechanical behaviours and life cycle assessment of sustainable multi-recycled aggregate concrete.

Multi-recycling of concrete waste presents a promising avenue for carbon-negative development and a circular economy. This study comprehensively assesses the triaxial mechanical performance and environmental impact of multi-recycled concrete (Multi-RAC) through three recycling cycles. The results reveal a triaxial failure mode similar to natural aggregate concrete (NAC). The peak stress and peak strain monotonically increase with confinement stress, showing a significant impact (enlarged by 171.4 % to 280.6 % and 397.4 % to 412.0 %, respectively) from 0 to 20 MPa. All P-values for recycling cycles and confining pressure are less than 0.05, with the confining pressure having a more significant effect. Three best-fit multivariate mixed models predict mechanical properties, and a modified elastoplastic model introduces the recycling cycles factor. Numerical simulations confirm the model's accuracy in predicting the triaxial mechanical properties of Multi-RAC. Comparative analysis reveals that the elastoplastic model-derived non-integral high order failure criterion outperforms the Willam-Warnke failure criterion and other conventional criteria. Regarding environmental impact, all indicators (GWP, POCP, AP, EP, and CED) decrease favourably with the increasing number of recycling cycles, with CED and EP playing the most significant roles. Compared to NAC, the five environmentally favorable indicators for RACIII decrease by 3.24 % to 50.6 %, respectively. These findings provide valuable insights for future research on developing eco-friendlier Multi-RAC for sustainable and green infrastructure.

Identification of porcine reproductive and respiratory syndrome virus inhibitors through an oriented screening on natural products.

Porcine reproductive and respiratory syndrome(PRRS) caused by porcine reproductive and respiratory syndrome virus(PRRSV) is one of the most infectious diseases in the swine industry worldwide, causing big economic losses. Vaccines are major weapons against PRRSV, however, current available vaccines have several limitations. Developing chemical drugs as alternatives is required. On the basis of traditional medical knowledge, we purposely selected 15 natural products originated from Chinese herbs with anti-infectious effects. Their antiviral activities were evaluated by PRRSV-induced cytopathic effect(CPE) on MARC-145 cells and reverse transcription polymerase chain reaction(RT-PCR) assay. Compounds ethoxysanguinarine(EOSG) and atractylodinol were found to be the hits which could significantly reduce PRRSV-associated CPE with 50% inhibited concentration(IC50) values of 7.9 and 39.4 µmol/L, respectively. Meanwhile, compounds ethoxysanguinarine and atractylodinol significantly decreased mRNA expression of ORF7 gene in a dose-dependent manner. Study results suggest that compounds ethoxysanguinarine and atractylodinol may be useful anti-PRRSV drugs for swine industry or the hits for further lead optimization.

Heavy metals immobilization of ternary geopolymer based on nickel slag, lithium slag and metakaolin.

To solve heavy metals leaching problem in the utilization of various industrial solid wastes, this work investigated the heavy metals immobilization of ternary geopolymer prepared by nickel slag (NS), lithium slag (LS), and metakaolin (MK). Compressive strength was measured to determine the optimum and appropriate mix proportions. The leaching characteristics of typical heavy metals (Cu (Ⅱ), Pb (Ⅱ), and Cr (Ⅲ)) in acid, alkali, and salt environments were revealed by Inductively Coupled Plasma (ICP). The heavy metals immobilization mechanism was explored by Mercury Intrusion Porosimetry (MIP), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM) tests. The experimental results show that the group with a mass ratio of NS, LS and MK of 1:1:8 exhibits the highest compressive strength, which reaches 69.1 MPa at 28 d. The ternary geopolymer possesses a desirable capacity for immobilizing inherent heavy metals, where the immobilization rates of Cu and Pb reach 96.69 %, and that of Cr reaches 99.97 %. The leaching concentrations of Cr and Pb increase when the samples are exposed to acidic and alkaline environments. Cu and Pb are mainly physically encapsulated in geopolymer. Additionally, immobilization of Cr mainly involves physical encapsulation and chemical bonding.

Detection of Hepatitis B virus in serum and liver of chickens.

Hepatitis B virus (HBV) is one of the most important human pathogens. Its existence in food animals could present a significant threat to public health. The objective of this study was to determine if HBV is present in serum and liver of chickens. A total of 129 serum samples from broiler chickens were collected for the detection of HBV antigens and antibodies, and 193 liver samples were tested for HBV DNA sequence by PCR and for the existence of HBV antigens by immunohistochemistry. The overall prevalence of HBsAg, anti-HBs, anti-HBc was 28.68%, 53.49%, 17.05%, respectively, whereas HBeAg, anti-HBe were barely detectable. Three serum samples were found to be positive for both HBsAg and HBeAg. Further analysis of these samples with transmission electron microscopy (TEM) revealed two morphologic particles with 20 nm and 40 nm in diameter, which were similar to small spherical and Danes particles of HBV. The viral DNA sequence identified in two of the chicken livers shared 92.2% of one known HBV strain and 97.9% nucleotide sequence of another HBV strain. Our results showed the existence of HBV in chickens. This would present a significant risk to people who work with live chickens or chicken products if HBV found in chicken could be confirmed to be the same as human HBV.

Seroprevalence and molecular detection of hepatitis E virus in Yunnan Province, China.

In this study, the prevalence and characteristics of hepatitis E virus (HEV) in pigs and the general population in the Yunnan province, China, were evaluated. Nine hundred sixty sera, 95 liver and 60 feces samples were randomly collected from pig farms and abattoirs, in addition 173 human sera were sampled in the provincial capital city for a serological survey and an RT-nPCR assay. The screening results showed that among 621 samples collected from five pig farms, the HEV-specific IgG positive rate ranged from 73.2% to 83.5%, and the overall seroprevalence was 78.9% (490/621). A further analysis revealed that the seroprevalence increased with age. The positive rate of human serum samples was 39.9% (69/173). HEV RNA was detected in five swine feces, six swine liver and one anti-HEV-IgM-positive human serum sample by RT-nPCR. Sequence and alignment of the 348-nt PCR-amplified products of 12 HEV strains identified nine distinct nucleotide sequences. Phylogenetic and molecular evolutionary analysis revealed that these nine sequences shared 84.2% to 100.0% nucleotide sequence identity with each other, with all isolates belonging to genotype 4 HEV and clustering with other Chinese swine and human HEV sequences determined earlier. This study results suggest that the prevalence of genotype 4 HEV is serious, both in pig herds and in the human population, and authorities should pay more attention to the prevalence of HEV in southwest China.

[Diagnosis of chronic schistosomiasis japonicum with the recombinant Sj26GST-Sj32 fusion protein by ELISA].

OBJECTIVE: To study the feasibility of rSj26GST-Sj32-IgG-ELISA for diagnosis of chronic schistosomiasis japonicum. METHODS: The Escherichia coli BL21 (DE3) with recombinant plasmid pET32alphaSj26GST-Sj32 were induced with isopropy-beta-D-thiogalactopyranosid (IPTG), and the expression product was analyzed by SDS-PAGE and purified by Ni-NTA kits. Schistosoma japonicum (Sj) adult worm antigen(SjAWA) was produced by routine method. The IgG antibodies were detected with the sera of chronic schistosomiasis japonicum by ELISA using recombinant Sj26GST-Sj32 (rSj26GST-Sj32) fusion protein and SjAWA, while the controls included the sera of patients with clonorchiasis, paragonimiasis westermani, alveolar echinococcosis, cystic echinococcosis, hepatitis B, pulmonary tuberculosis and healthy people. RESULTS: The sensitivity and specificity of rSj26GST-Sj32 fusion protein were 95.00% (38/40) and 97.67% (42/43) respectively, they were 92.50% (37/40) and 97.67% (42/43) respectively in SjAWA groups. There were no difference in sensitivity and specificity between rSj26GST-Sj32 and SjAWA (P > 0.05). There were different cross reactions in clonorchiasis sinensis and paragonimiasis westermani between the two methods. The cross reaction with SjAWA was 20.00% (2/10) in patients with alveolar echinococcosis, but no cross reaction with rSj26GST-Sj32 (P > 0.05). CONCLUSION: rSj26-Sj32-IgG-ELISA probably could be applied to immunodiagnosis for chronic schistosomiasis japonicum.

[Detection of specific IgG in the sera of patients with chronic schistosomiasis japonica by dot-ELISA with the recombinant Sj26-Sj32 fusion protein].

OBJECTIVE: To study the diagnostic value of the Dot ELISA with rSj26-Sj32 fusion protein for chronic schistosomiasis japonica. METHODS: rSj26-Sj32 fusion protein and SjAWA were used to establish the HRP-IgG-Dot-ELISA. Serum samples from patients with chronic schistosomiasis japonica (40 cases), clonorchiasis sinensis (21 cases), paragonimiasis westermani(13 cases), alveolar echinococcosis (10 cases), cystic echinococcosis(9 cases), hepatitis B(20 cases), pulmonary tuberculosis (20 cases) and healthy persons (43 cases) were examined. RESULTS: Sensitivity and specificity were respectively 92.5% (37/40) and 95.4% (41/43) for rSj26-Sj32-Dot-ELISA and 95.0% (38/40) and 93.0% (40/43) for SjAWA-Dot-ELISA, and there was no significant difference between two antigens (P > 0.05). There were different cross reactions to the sera of patients with clonorchiasis sinensis, paragonimiasis westermani or alveolar echinococcosis, but no cross reaction to the sera of patients with cystic echinococcosis, hepatitis B or pulmonary tuberculosis. The positive and negative predictive value and efficiency of diagnosis of rSj26-Sj32-Dot-ELISA for chronic schistosomiasis japonica were 84.1% (37/44), 97.7% (129/132), and 94.3% (166/176), respectively, and those of SjAWA-Dot-ELISA were 77.6% (38/49), 98.4% (125/127), and 92.6% (163/176), respectively. There was no significant difference between the two methods (P > 0.05). CONCLUSION: rSi26-Si32 fusion protein can be applied to immunodiagnosis for chronic schistosomiasis japonica.

Participatory and Transdisciplinary Studies of Brucella Infection in Humans and Animals in Yunnan Province, China-Lessons Learned.

Brucellosis is an important zoonosis occurring globally. In addition to the risk for disease in humans, the disease causes production losses, since the disease in livestock is characterized by abortion and other reproductive failures. The disease is a public health concern in China, but no information is available on knowledge, perception and awareness of potential risk groups such as farmers, butchers and animal health workers; yet successful control requires compliance of those affected groups to be effective. Following the principles of the Ecohealth approach, emphasis was given to participation of all relevant stakeholders, use of qualitative and quantitative tools, and cross-sectorial collaboration. Data collection included on-farm questionnaires (N = 192) and collection of bulk milk samples of goat (N = 40), cattle (N = 45) and buffalo (N = 41) from farms, as well as serum samples (N = 228) from humans. Milk samples were tested with an ELISA for presence of antibodies, while a serum agglutination test was used for human samples. Qualitative work included 17 focus group discussion (FGD) with villagers and 47 in-depth interviews (IDI) with village animal health workers, doctors, and butchers, focused on knowledge, perception and awareness on zoonoses including brucellosis. Results from questionnaires indicate that abortions are a common problem; cattle with abortion history are kept for further insemination and the milk still consumed or sold. Antibodies against Brucella were detected in cows' (5/45) and goats' (1/40) milk samples, and in human samples (5/126) in Yiliang, while in Mangshi, all buffalo (N = 41) and humans (N = 102) were negative. FGD and IDI results showed an alarmingly low knowledge and awareness on zoonoses; particularly, low awareness about brucellosis was noted, even among the professional groups. Collaboration between village animal health workers and doctors was uncommon. No confirmed brucellosis cases were found in retrospective investigation of hospital and veterinary stations. This study demonstrates the presence of brucellosis in livestock and humans in Yunnan, indicating a non-negligible risk for humans. It is also made apparent that there is a need for increased awareness among both farmers and professionals in order to reduce the risk of zoonotic transmissions.

Prevalence of a virus similar to human hepatitis B virus in swine.

BACKGROUND: The objective of this study is to established evidence of the existence of a novel member of the hepadnavirus family endemic in swine. Temporarily this virus was designated as swine hepatitis B virus (SHBV). This SHBV can be detected by using human hepatitis B virus diagnostic kits including ELISA, immunohistochemical staining, and transmission electron microscopy (TEM). Also seroprevalence of pig farms in Beijing, China, and pathological features of SHBV infection was determined. RESULTS: Screened result shows that overall prevalence of HBsAg was 24.8%, closed to that of anti-HBsAg, whereas HBeAg and anti-HBe were barely detectable. The distribution of HBsAg and HBcAg was examined by immunohistochemistry of liver samples. Typical hepatitis pathological change, such as spotty parenchymal cell degeneration, necrosis of hepatocytes and proliferation of fibrous connective tissue were observed during histopathological analysis. Analysis of HBsAg-positive serum with TEM revealed two morphologic forms, 20 nm and 40 nm sized particles, similar to small spherical and Danes particles of HBV. Observation of the ultrastructure of the liver also found HBV-like particles in the nucleus of hepatocytes. CONCLUSION: Our research result implies that SHBV could be a causative agent of swine. The discovery of SHBV will unveil novel evolutionary aspects of hepatitis and provides new information for further hepadnavirus research.

Genetic diversity of the S10 RNA segment of field and vaccine strains of bluetongue virus from the P. R. China.

Bluetongue virus (BTV) infection of ruminants is endemic throughout tropical and subtropical regions of the world. However, the molecular epidemiology of BTV infection in China has not yet been reported. In this study, the S10 gene segments from 30 BTV isolates, one attenuated BTV strain, one vaccine BTV strain, and one South Africa BTV prototype strain, were sequenced. Phylogenetic analysis of the S10 genes showed that Chinese BTV isolates could be classified into two phyletic subgroups, and the clustering of Chinese BTV viruses was dependent on their geographical origin and the number of generations for which they had been propagated, rather than their host species or year of isolation.

[Dynamic observation on splenocyte subsets in mice immunized with recombinant Bb-Eg95-EgA31 vaccine of Echinococcus granulosus].

OBJECTIVE: To dynamically observe changes of subsets of splenocytes in mice immunized with recombinant Bifidobacteria bifidum (Bb)-Eg95-EgA31 vaccine of Echinococcus granulosus (Eg). METHODS: BALB/c mice were vaccinated by 5 x 10(8) colony forming unit (CFU) orally and 5 x 10(5) CFU intranasally respectively. Mice were killed on week 0, 2, 4, 6, 8, 10, 12, 14, 16, 18 and 20 after immunization respectively, and spleens were separated for cell preparation. CD4+ and CD8+ T cells were determined by flow cytometry (FCM), with MRS as control. RESULTS: In the oral immunization group, CD4+ cells showed a significant increase during the 4th-10th week after vaccination, and reached the highest level on the 6th week, whereas no obvious changes in CD8+ cells numbers were observed. In the intranasal immunization group, CD4+ cells showed an obvious increase during the 4th-8th week after vaccination, and reached the highest level on the 6th week, CD8+ subsets had no obvious changes. CONCLUSION: CD4+ T cell cells may play a key role in immune response in mice immunized with the recombinant Bb-Eg95-EgA31 vaccine of Echinococcus granulosus.