新疆生产建设兵团第十师羊小反刍兽疫抗体监测与评价

为了评估新疆生产建设兵团第十师北屯市(以下简称师市)羊群小反刍兽疫强制免疫效果,应用酶联免疫吸附试验(ELISA)对2017-2020年全师8个农牧团场采集的4 010份血清进行小反刍兽疫抗体检测,并按单位、年份、类别对检测结果进行了统计分析。结果表明,2018-2020年全师8个农牧团场小反刍兽疫血清抗体平均合格率为84.69%(3 396/4 010),均符合国家农业农村部相关规定,高于平均值的三家单位是E 87.22%(157/180)、G 86.45%(268/310)、H 88.67%(798/900),合格率最低的是D 76.11%(137/180);养殖合作社的抗体合格率为84.81%(1 340/1 580),养殖大户为84.65%(2 057/2 430)均接近于平均合格率,两者差异不显著(P>0.05)。总体来看,师市羊群小反刍兽疫免疫效果较好,为确保师市辖区内重大动物疫病免疫无疫提供技术保障。     

Advancing the deer calcaneus model for bone adaptation studies: ex vivo strains obtained after transecting the tension members suggest an unrecognized important role for shear strains

Sheep and deer calcanei are finding increased use as models for studies of bone adaptation, including advancing understanding of how the strain (deformation) environment influences the ontogenetic emergence of biomechanically relevant structural and material variations in cortical and trabecular bone. These artiodactyl calcanei seem ideal for these analyses because they function like simply loaded short‐cantilevered beams with net compression and tension strains on the dorsal and plantar cortices, respectively. However, this habitual strain distribution requires more rigorous validation because it has been shown by limited in vivo and ex vivo strain measurements obtained during controlled ambulation (typically walking and trotting). The conception that these calcanei are relatively simply and habitually loaded ‘tension/compression bones’ could be invalid if infrequent, though biologically relevant, loads substantially change the location of the neutral axis (NA) that separates ‘compression’ and ‘tension’ regions. The effect on calcaneus strains of the tension members (plantar ligament and flexor tendon) is also not well understood and measuring strains after transecting them could reveal that they significantly modulate the strain distribution. We tested the hypothesis that the NA location previously described during simulated on‐axis loads of deer calcanei would exhibit limited variations even when load perturbations are unusual (e.g. off‐axis loads) or extreme (e.g. after transection of the tension members). We also examined regional differences in the predominance of the three strain modes (tension, compression, and shear) in these various load conditions in dorsal, plantar, medial, and lateral cortices. In addition to considering principal strains (tension and compression) and maximum shear strains, we also considered material‐axis (M‐A) shear strains. M‐A shear strains are those that are aligned along the long axis of the bone and are considered to have greater biomechanical relevance than maximum shear strains because failure theories of composite materials and bone are often based on stresses or strains in the principal material directions. We used the same load apparatus from our prior study of mule deer calcanei. Results showed that although the NA rotated up to 8° medially and 15° laterally during these off‐axis loads, it did not shift dramatically until after transection of all tension members. When comparing results based on maximum shear strain data vs. M‐A shear strain data, the dominant strain mode changed only in the plantar cortex – as expected (in accordance with our a priori view) it was tension when M‐A shear strains were considered (shear : tension = 0.2) but changed to dominant shear when maximum shear strain data were considered (shear : tension = 1.3). This difference leads to different conclusions and speculations regarding which specific strain modes and magnitudes most strongly influence the emergence of the marked mineralization and histomorphological differences in the dorsal vs. plantar cortices. Consequently, our prior simplification of the deer calcaneus model as a simply loaded ‘tension/compression bone’ (i.e. plantar/dorsal) might be incorrect. In vivo and in finite element analyses are needed to determine whether describing it as a ‘shear‐tension/compression’ bone is more accurate. Addressing this question will help to advance the artiodactyl calcaneus as an experimental model for bone adaptation studies.     

Marginal leakage of Gallium Alloy root-end fillings: an in-vitro assessment

The sealing ability of amalgam and Gallium Alloy Gallium Filling (GF) root-end fillings was evaluated in vitro using a highly uniform collection of sheep incisor roots. Following ultrasonic canal debridement and orthograde obturation with gutta-percha and sealer, root-end cavities were prepared in 100 roots and filled with amalgam (50 teeth) or Gallium Alloy GF (50 teeth). Twenty-five teeth from each group were subjected to immediate dye leakage assessment under vacuum conditions with methylene blue dye (2%), pH 7. Linear dye penetration was measured following longitudinal splitting. The other 25 teeth from each group were incubated in Ringer's solution for 12 weeks before leakage assessment by the same method. Control teeth were included in each component of the study. Mean linear dye penetration was: amalgam—5.17mm at baseline, 2.33mm after 12 week's incubation; Gallium Alloy GF—2.21mm at baseline, 1.41mm after 12 week's incubation. The apical marginal seal of both materials improved significantly following storage in Ringer's solution (P < 0.001). Gallium Alloy GF provided a better apical seal than amalgam, both at baseline and following storage (P < 0.001). Subjective evaluation of the general handling characteristics of Gallium Alloy GF revealed that it was a more difficult material to manipulate than amalgam, largely because of its wetting ability and consequent adhesion to dental instruments.     

Ovine periodontitis as a potential model for periodontal studies. Cross-sectional analysis of clinical,microbiological, and serum immunological parameters

OBJECTIVES: : To investigate infection and host immunity patterns in sheep with naturally occurring "broken-mouth" periodontitis. MATERIALS AND METHODS: : Eight periodontally healthy (HS) and eight periodontally diseased ewes (PDS) were selected. Subgingival plaque and sera were collected and examined for evidence of human periodontitis-associated pathogens. Serum IgG titers were measured by ELISA to multiple strains of Porphyromonas gingivalis, Bacteroides forsythus, Dichelobacter nodosus, Actinobacillus actinomycetemcomitans, Prevotella intermedia, and Fusobacterium nucleatum as well as several purified antigens (cysteine proteases, LPS, K, and fimbriae). RESULTS: : Neither the organism Aa nor antigens to Aa were found in any animal. Most animals were positive for Pg, Bf, and Pi, but DNA probes detected no difference between HS and PDS relative to amounts of pathogens in subgingival plaque. PDS had significantly higher serum IgG titers to all Pg strains, to 50% of Bf strains, to the Pi and Fn strains, and to fimbriae and the two cysteine proteases (p-values ranging from 0.05 to 0.001). Regression analysis demonstrated a significant association between number of teeth lost and serum IgG antibody titers to whole-cell sonicate antigens of P. gingivalis strains (p<0.01) and body weight (p<0.01). CONCLUSIONS: : The presence of pathogens associated with periodontitis was reflected in differences in serum IgG titers between healthy and diseased sheep. This may have influenced animal body weight and might have systemic health and economic consequences. The data suggest that susceptible and non-susceptible sheep can be identified for periodontal research.     

Exploratory investigation of Q fever in apparently healthy meat sheep flocks in Belgium

Q fever is a cosmopolitan disease affecting both humans and many animal species. Although sheep are often implicated in human Q fever outbreaks, the disease remains largely underestimated in meat sheep flocks. In order to fulfil this gap, a preliminary study was performed aiming to investigate the serological and molecular aspects of infection with Coxiella burnetii among meat sheep flocks in Belgium. Five Belgian sheep flocks were recruited for this work. Indirect ELISA was used, and in addition, real‐time PCR was performed on samples of milk, rectal and vaginal swabs, to understand the dynamics of bacterial shedding. Despite the low overall apparent seroprevalence of 1.39% (95% CI : 0.04–7.5), a high rate of bacterial shedding was found, with 27.7% of tested sheep (N  = 72) with a positive result to PCR , especially through the rectal and vaginal routes and in seronegative animals. Furthermore, Coxiella burnetii DNA was detected in 26.76% of seronegative animals. It can be concluded that an overall good clinical condition of the sheep cannot be used to exclude the presence of C. burnetii in a flock. Furthermore in the diagnosis of Q fever in sheep, serology alone was not a sensitive diagnostic tool. On the contrary, molecular biology allowed to detect bacterial shedding, which is an essential element in order to assess the risk due to the contact with shedding animals. At the light of these results, the role of meat sheep flocks in the epidemiology of Q fever in Belgium needs to be better understood.     

Serological relationship between a novel ovine pestivirus and classical swine fever virus

The genus Pestivirus comprises globally distributed members of the family Flaviviridae, which cause severe losses in livestock. The most common species of the genus are bovine viral diarrhoea virus type 1 (BVDV‐1) and type 2 (BVDV‐2), classical swine fever virus (CSFV) and border disease virus (BDV). Recently, a novel ovine pestivirus was repeatedly detected in aborted lamb foetuses on a farm located in the Brescia Province (Italy). Complete genome characterization of this isolate showed that it was highly divergent from known pestivirus species and that it was genetically closely related to CSFV. The aim of this study was to determine the serological relatedness between the identified novel pestivirus and BVDV, BDV and CSFV selected strains for which homologous serum was available, by antigenic characterization performed using cross‐neutralization assays. The serological relatedness was expressed as the coefficient of antigenic similarity (R). Both field and specific antisera raised against the ovine pestivirus neutralized the CSFV reference strain Diepholz with titres significantly higher than those specific for the BDV and BVDV strains. Furthermore, the calculated R values clearly indicated that the novel ovine pestivirus is antigenically more related to CSFV than to ruminant pestiviruses, in agreement with the results of the genomic analysis. This would have severe consequences on CSFV serology in the event of a switch to porcine hosts with implications for CSFV surveillance and porcine health management.     

Interleukin-1β transfer across the blood–brain barrier in the ovine fetus

Pro-inflammatory cytokines contribute to hypoxic–ischemic brain injury. Blood–brain barrier (BBB) dysfunction represents an important component of hypoxic–ischemic brain injury in the fetus. Hypoxic–ischemic injury could accentuate systemic cytokine transfer across the fetal BBB. There has been considerable conjecture suggesting that systemic cytokines could cross the BBB during the perinatal period. Nonetheless, evidence to support this contention is sparse. We hypothesized that ischemia–reperfusion increases the transfer of systemic interleukin-1β (IL-1β) across the BBB in the fetus. Ovine fetuses at 127 days of gestation were studied 4 hours after 30 minutes of bilateral carotid artery occlusion and compared with a nonischemic group. Recombinant ovine IL-1β protein was expressed from an IL-1β pGEX-2 T vector in E. coli BL-21 cells and purified. The BBB function was quantified in 12 brain regions using a blood-to-brain transfer constant with intravenous ¹²⁵I-radiolabeled IL-1β (¹²⁵I-IL-1β). Interleukin-1β crossed the intact BBB in nonischemic fetuses. Blood-to-brain transport of ¹²⁵I-IL-1β was higher (P<0.05) across brain regions in fetuses exposed to ischemia–reperfusion than nonischemic fetuses. We conclude that systemic IL-1β crosses the intact fetal BBB, and that ischemia–reperfusion increases transfer of this cytokine across the fetal BBB. Therefore, altered BBB function after hypoxia–ischemia facilitates entry of systemic cytokines into the brain of the fetus.