禽流感的临床特征及疫苗防治

禽流感的爆发,严重影响养禽业的发展,也造成了巨大的经济损失,特别是高致病性禽流感对人类的健康已经构成了严重的威胁。本文针对目前禽流感病毒的致病性、抵抗力、临床症状、病理变化等临床特征及疫苗防治等方面进行了综述,对今后进行防控禽流感提供一定的技术参考。     

禽流感的诊断检测及防治研究进展

高致病力禽流感（HPAI）被国际兽疫局列为A类烈性传染病,本文对HPAI的诊断检测技术及防制对策进行了综述,总结了禽流感诊断方法如病原学、血清学、分子生物学等方面的最新研究进展,分析了禽流感疫苗预防禽流感的效果和缺点。     

泰安及周边地区鸭禽流感血清学检测分析

为了解泰安及周边地区肉鸭禽流感的免疫状况,为该地区鸭禽流感的有效防控提供正确的理论依据,对山东泰安及周边地区45个养鸭场高致病性禽流感免疫情况进行了调查,并采集720份血清进行了H5禽流感血清学检测,结果表明：种鸭及大多数商品蛋鸭群禽流感的免疫状况较好,但针对变异毒株的抗体水平较低;少数商品蛋鸭群及绝大多数商品肉鸭群未进行禽流感免疫,商品蛋鸭及中后期肉鸭群抗体水平几乎为零,故均为易感鸭群,若遇禽流感疫情会存在一定的发病风险,应加强禽流感疫苗免疫。     

禽流感及其防制建议

禽流感是一种呈世界性分布、严重危害养禽业的重要传染病,对人类健康的威胁已逐渐显现。本文对禽流感的病原、流行病学、症状和病变、诊断及防制等方面进行了全面介绍,以期提高人们对禽流感的认识,为正确科学地防控禽流感提供参考。     

泰安及周边地区禽流感免疫状况调查分析

为了解泰安及周边地区肉鸭禽流感的免疫状况,为该地区鸭禽流感的有效防控提供理论依据,对山东泰安及周边地区45个养鸭场高致病性禽流感免疫情况进行了调查,并采集720份血清进行了H5禽流感血清学检测,结果表明:种鸭及大多数商品蛋鸭群禽流感的免疫状况较好,但针对变异毒株(H5Re-6)的抗体水平较低。     

行业动态

两岸四地探讨联手防禽流感本刊讯:5月10～11日,禽流感和人感染高致病性禽流感研讨会在香港举行,内地及港澳台专家就禽流感防控有关问题进行了深入交流。与会专家分别介绍了内地及港澳台禽流感防控的总体情况,并就禽流感应急预案主要内容及实施、疫情监测与报告、禽流感诊断研究及工作开展、禽流感疫苗研究生产及质量监管、病原微生物实验室生物安全管理等内容进行了讨论。与会的港澳台专家认为,内地在禽流感疫情监测、防控措施落实及宣传教育等方面的做法很有借鉴意义,并希望进一步加强与内地在候鸟监测、实验室研究和免疫效果监测等方面的…     

禽流感及其防制建议

禽流感是一种呈世界性分布、严重危害养禽业的重要传染病，对人类健康的威胁已逐渐显现。本文对禽流感的病原、流行病学、症状和病变、诊断及防制等方面进行了全面介绍，以期提高人们对禽流感的认识，为正确科学地防控禽流感提供参考。     

禽流感免疫水平低下的原因剖析

近几年，世界许多国家相继发生了禽流感疫病，禽流感疫情形势十分严峻。多年来，禽流感油乳剂灭活苗在东阳市得到了广泛应用，东阳市畜牧兽医局化验室对大批次、大批量的家禽进行了禽流感抗体监测情况来看，还有许多养殖专业户的家禽的禽流感免疫效果不理想。为此就禽流感免疫水平低下的原因及对策进行了重点分析落实。     

全球研发成功3种禽流感人用疫苗株

人禽流感疫苗研发及应用策略国际研讨会近日在北京召开.来自世界卫生组织及十几个国家的代表,就当前禽流感疫情与人禽流感疫苗研发最前沿信息展开了交流,并对疫苗研发及应用策略进行了研讨.     

禽流感病毒分子生物学研究进展

禽流感的爆发,给全世界养禽业造成了巨大的经济损失,禽流感病毒(AIV)更是危害人类和养禽业的重要病原。目前,禽流感病毒的研究主要集中在分子生物学方面,本文就禽流感病毒的形态结构、基因组结构、血凝素和神经氨酸酶的结构和功能及遗传变异等分子生物学方面进行了综述,对今后防治高致病性禽流感提供一定的参考。     

感染高原鼠兔的皮蝇蛆16SrRNA基因序列研究

利用分子生物学技术对高原鼠兔感染皮蝇蛆16SrRNA基因进行了研究,扩增出长度为551 bp的序列,克隆测序,将其序列与GenBank中的皮蝇科、胃蝇科的序列进行了聚类分析,并构建分子进化树.结果显示,感染高原鼠兔的皮蝇蛆与皮蝇科的皮蝇蛆遗传距离更近,在一个大的进化树分支上,基因片段同源性84.6％～88.4％之间,与胃蝇科的红尾胃蝇基因片段同源性60.1％ ～64.4％之间.几株感染高原鼠兔的皮蝇蛆之间的基因片段同源性94.4％～99.6％之间.     

Pathogenicity of Eimeria praecox alone or associated with Eimeria acervulina in experimentally infected broiler chickens

Eimeria praecox and Eimeria acervulina are two species of coccidia parasites infecting chickens, which develop in the duodenum. The purpose of this study was to evaluate the pathogenicity of E. praecox and to study interactions of this coccidium with E. acervulina. The results showed that the pathogenicity of E. praecox was related to the infective dose, and that its impact on individual weight and weight gain was significant from the lowest administered dose: 5000 oocysts per bird. No morbidity was observed, even with the highest infective dose, but faecal consistency alteration was higher with increasing infective doses. No consistent lesion was observed. When E. praecox was associated with E. acervulina with a low infective dose, performance deterioration seemed to be an additional effect of the two species. However, in the case of heavy infections, signs worsened along with duration of negative impact on growth, compared to a mono-infection.     

Further study of Codiostomum struthionis (Horst, 1885) Railliet and Henry, 1911 (Nematoda, Strongylidae) parasite of ostriches (Struthio camelus Linnaeus, 1758) (Aves, Struthioniformes)

Codiostomum struthionis is a nematode parasite of the ostrich caecum. Little is known about its pathology, being considered by many authors as a non-pathogenic parasite. Infections by C. struthionis are sometimes overlooked because its eggs are indistinguishable from another ostrich nematode, Libyostrongylus spp. Fecal cultures and infective larvae identification are necessary for proper identification. The aim of this study is to provide improved morphological characterization of adults and infective larvae of C. struthionis. Ten caeca of adult ostriches were collected and washed in 0.09% saline solution. Male and female nematodes were collected and quantified separately. Nematodes were fixed in A.F.A. for optical microscopy or fixed in Karnovsky solution for scanning electron microscopy. To obtain infective larvae, fecal samples were collected at sites of high concentration of parasites in the caeca and fecal cultured. The resultant larvae were identified and measured with light microscope at 400x. Nine of the 10 slaughtered ostriches were parasitized by C. struthionis. All nematodes were found in the distal third of the caeca. A total of 566 parasites were recovered (234 males and 332 females). All the cultured larvae had characteristics of C. struthionis (rounded cephalic region with a flat extremity, an acute larvae tail termination and a long and filamentous sheath tail). All the adult parasites were characterized as C. struthionis. Through the analysis of the infective larvae it was determined that the morphology of the larvae tail was the best trait to use in the distinction of this species (live bird diagnosis).     

雏鸡感染堆型艾美耳球虫及体内一氧化氮的生成

本研究利用Griess反应监测了雏鸡感染堆型艾美耳球虫(Eimeriaacervulina)后血浆NO     

呼和浩特市周边地区奶牛球虫病流行病学调查

作者采用常规粪便漂浮法,对呼和浩特市周边地区奶牛养殖牧场、养殖小区和养殖农户的约3000头奶牛进行了球虫病流行病学调查。经过统计分析结果如下:奶牛球虫病总平均感染率为9.54%,其中犊牛的平均感染率最高,为17.59%,育成牛的平均感染率为10.62%,青年牛的平均感染率为7.68%,泌乳期牛的平均感染率为2.28%;养殖农户奶牛球虫病平均感染率最高为14.58%,最低为7.39%;养殖牧场奶牛球虫病平均感染率最高为6.67%,最低为2.73%;养殖农户奶牛球虫病平均感染率,均高于养殖牧场和养殖小区奶牛球虫病的平均感染率。经过初步形态学鉴定,该地区优势虫种为邱氏艾美耳球虫(E zurnii)、牛艾美耳球虫(Ebovis)和阿沙卡等孢球虫(isospora akscaica)3种。     

牛腹腔唇乳突丝虫及其感染蚴扫描电镜观察

对牛腹腔唇乳突丝虫雌性成虫及其感染蚴扫描电镜观察结果表明,成雌虫头端的口孔、角质围口环、侧唇、背腹唇、亚中乳突和头感器均清晰可见,体表为环行皮纹和纵行皱褶,尾部可见侧附肢、肛孔及尾端刺状突起物,仅极少数成雌虫尾端呈纯圆光滑样,没有突起物.感染蚴的头部基本具备了成虫头部的构造,但发育较原始,其乳交数量较成虫少,尾部可见肛孔、肛唇及一个侧乳突.     

Partial biochemical and serological characterization of exsheathing fluid and somatic extracts of infective larvae and adult females of Haemonchus contortus.

Exsheathing fluid from infective larvae of Haemonchus contortus may contain antigens which induce protective immunity upon infection in sheep. In this study, a rapid method of preparing exsheathing fluid was used to determine its biological activity, purity and antigenic complexity. Protein in exsheathing fluid ranged from 21-59.5 micrograms/mL and no carbohydrate was detected. Gel filtration showed a single broad peak which retained biological activity and polyacrylamide gel electrophoresis demonstrated a single band staining with Coomassie blue. Biological activity of exsheathing fluid was present in extracts of infective larvae but not in extracts of exsheathed larvae or in extracts of adult female H. contortus. Rabbit antiserum against exsheathing fluid proteins cross-reacted with infective larvae extracts but not with adult female worm extracts. Immunoelectrophoresis of exsheathing fluid proteins against this antiserum showed a single polydisperse precipitin line. Thus, exsheathing fluid produced by the rapid method is a pure preparation of a biologically active and antigenically simple material suitable for further studies of protective immunity in sheep to H. contortus.     

Aleutian disease in the ferret

Ferrets inoculated with Aleutian disease (AD)-infective material of mink origin harbored the infective agent for at least 136 days after inoculation. In contrast, hamsters given a similar inoculum of infective material no longer harbored the infective agent at 21 days postinoculation. During the infective period, neither ferrets nor hamsters had any detectable illness. However, in certain ferrets, massive periportal lymphocytic infiltrates were observed. A survey of ferrets from different ranches revealed similar lymphocytic infiltrates only in ferrets raised on a ranch which had AD-infected mink.     

Development and survival of Haemonchus contortus larvae on pasture at Vom,Plateau State,Nigeria

The development and survival of the eggs of Haemonchus contortus on pasture at Vom were studied by depositing faecal pellets on grass plots over a period of 12 months. Development and survival to the infective larvae occurred throughout the study except during the dry season months of December to April. More infective larvae were recovered from the herbage in June, July and August than in other months. The survival time of the infective larvae ranged from 2 weeks in October to 10 weeks in June, July and August. Rainfall was the most important epizootiological factor influencing the development and survival of the infective larvae. Temperature was not a limiting factor.     

Development and survival of free-living stages of equine strongyles under laboratory conditions

In a series of laboratory studies the optimum conditions for the development and survival of the free-living stages of strongyle parasites occurring in horses in tropical north Queensland were determined. No differences in behaviour were noted between the strongyle species. Development to the infective stage occurred only between 10 and 35 degrees C. The rate was affected by temperature, taking 15-24 days and 3 days, respectively, at the lowest and highest temperatures for the developing stages to reach the infective third stage. Yields of infective larvae were very low outside the range 20-33 degrees C, and were highest at 28 degrees C. Survival of infective larvae was good between 20 and 33 degrees C, and large numbers were recovered after 3 months in faeces incubated at 20-28 degrees C. At 33 and 37 degrees C larval survival was affected by the moisture content of the faeces, with infective larvae surviving better in dry than in moist faeces; even a residual moisture level of 40% significantly reduced the number of larvae recovered from faeces incubated at 37 degrees C for 1 month. Moisture also affected larval development, especially at the higher temperatures of 25-39 degrees C. When faecal moisture content fell to less than or equal to 20% by 3 days, larvae which had not yet reached the infective stage were still pre-infective at 7 days, while all larvae in faeces with adequate moisture had reached the infective third stage. It was not possible to determine the critical faecal moisture level below which larval development ceased, however, 28 degrees C (range 25-33 degrees C) was found to be the optimum temperature. Larval development was very rapid and yields of infective larvae highest at this temperature.