The role of fish movements and the spread of infectious salmon anemia virus (ISAV) in Chile, 2007–2009

Infectious salmon anemia virus (ISAV) infection is a constant major threat to farmed and wild Atlantic salmon worldwide. Many epidemics have recently been reported in the most important salmon farming regions of the world, including Chile (2007–2009), where ISAV generated the most important disease and economic crisis in history of the salmon industry of the country. The spread of ISAV within a region is most likely by local or neighborhood spread from an infected farm; however, there is evidence that anthropogenic activities, such as movement of live or harvested fish or their byproduct, may have played a more important role than environmental or passive transmission in the 2007–2009 outbreak. Atlantic salmon farms (n = 421) were retrospectively followed from stocking to harvesting in southern Chile at the time of the ISAV epidemic (2007–2009). The effect of husbandry and spatial risk factors, in addition to contact-network risk factors, which were obtained from the social network analyses, on time to first ISAV infection was estimated using a multivariable Cox proportional hazards model. Five variables were retained in the final fitted model: co-existing multiple generations on a farm (hazard ratio [HR] = 2.585), mean smolt weight at stocking greater than 120 g (HR = 1.165), farm area (per km²) (HR = 1.005), and increased number of shipments entering a farm, i.e. the farm input degree (HR = 1.876) were associated with reduced time to infection; whereas time-to-infection was longer for farms located farther from an ongoing ISAV outbreak (HR = 0.943). It was demonstrated that movements of latently infected fish resulted in approximately 7 outbreaks, and potentially explain about 6% of the total number of cases during the epidemic. Results from this study provide new information about the mechanisms of spread of ISAV in one the largest documented ISAV epidemics in the world. Findings may be used to support the design and implementation of risk-based surveillance and control programs that may help to prevent, detect and control future ISAV outbreaks.     

异育银鲫溶血性腹水病的组织显微病理研究

本文报导了1986年以来，在上海郊县及江苏等省市引起异育银鲫大量死亡的疾病、目前在国内外尚未见有报导，是一种新的暴发性鱼病。为此我们进行了病鱼组织显微病理变化的观察。现将该病暂定名为异育银鲫溶血性腹水病。病鱼体表充血、出血，病情严重时肛门红肿，眼球突出，腹部膨大，腹腔内有淡黄色或红色腹水，肠壁充血发炎；有的病鱼骨骼肌也充血，鳞片竖起。各组织器官都发生病变，其中尤以肝、脾、肾为严重；肝脏肿大，质地极度柔软，呈弥漫性坏死，肝细胞的胞浆内有被苏木素深染的丝状物；脾脏大片坏死解体成淡红色一片；肾小体坏死，以至解体，肾小管及造血细胞也多数发生病变，并有细胞管型．     

山东省部分养殖场点马属动物主要病毒疫病调查

为了解山东省马属动物主要病毒疫病流行现状,采集青岛市2个马场以及济南、聊城和德州等驴养殖密集地市4个驴场的血清和全血样品各694份,分别进行马传染性贫血、H3N8亚型马流感血清抗体检测和非洲马瘟病原检测。结果显示:马传染性贫血、非洲马瘟检测全部为阴性,H3N8亚型马流感群体阳性率和样品阳性率分别为100%(6/6)和81.38%(520/639)。结果表明:马传染性贫血和非洲马瘟在这些养殖场点已得到很好的预防,但鉴于国外严峻的疫情形势,需要继续加强监测,防止病原传入;H3N8亚型马流感流行较为普遍,感染率较高,需要重点加强防控。本调查为山东省马属动物疫病防控提供了数据参考。     

马传贫弱毒疫苗接种马(骡)免疫反应动力学研究

本试验对注射马传贫弱毒疫苗后的马(骡)50匹,分别进行了体温、血液学、血清抗体及血液中T淋巴细胞等项目的检测。在此基础上,探讨了注苗后马(骡)免疫反应及其动态规律。提出注苗马(骡)在T细胞恢复到正常水平前,仍有感染强毒的可能,因此对马(骡)仍需进行监控。     

山梨醇铁注射液预防仔猪缺铁性贫血和促进生长的研究

采用四种补铁制剂于仔省3日龄时分别一次肌肉注射,测定血红点白含量、增重等指标,研究山梨醇铁及其它类似制剂对预防仔猪贫血及促进生长的影响。试验结果表明:①各用药组仔猪各项指标均高于对照组;②福铁维组和100mg Fe/ml山梨醇铁组仔猪的血红蛋白含量升高及增重都极显著地高于对照组(P<0.01),期末增重比值分别达到135.04％与119.02％;③100mg Fe/ml山梨醇铁注射液吸收良好,无毒副作用,对预防仔猪缺铁性贫血及促进生长有较明显的效果,优于国内同类产品。     

洋姜治疗仔猪贫血的试验研究

本研究以洋姜治疗仔猪贫血,通过检测血清铁、血红蛋白、红细胞压积、转铁蛋白、网织红细胞数等指标的变化,验证该药对仔猪贫血的治疗效果。结果表明,饲喂洋姜7d后,试验组中血清铁和红细胞压积显著高于对照组(P0.05),试验组血红蛋白、转铁蛋白浓度与对照组相比,差异极显著(P0.01)。饲喂15d后,试验组仔猪血清铁、血红蛋白、红细胞压积、转铁蛋白浓度与对照组相比,差异极显著(P0.01)。而试验期内2组间网织红细胞数差异均不显著(P0.05)。说明洋姜能显著提高血液中铁离子、血红蛋白水平,有效增加转铁蛋白饱和度,对治疗仔猪贫血具有较好的效果。     

葡聚糖铁治疗犊牛贫血的试验研究

本研究以葡聚糖铁治疗犊牛贫血,通过检测血液中血红蛋白、胆固醇、丙二醛(MDA)、过氧化氢酶(CAT)等指标的变化,验证该药对贫血的临床治疗效果。结果表明,试验组血液中血红蛋白、铁离子浓度显著高于对照组(P0.05),试验组中胆固醇、MDA低于对照组,差异极显著(P0.01),而试验组中CAT浓度显著高于对照组(P0.05)。说明葡聚糖铁可显著提高铁离子浓度、血红蛋白含量,纠正由于缺铁造成的氧化应激,治疗犊牛贫血具有较好的效果。