犬瘟热疫苗弱毒的复壮与免疫试验

将一株犬瘟热疫苗株病毒通过Ｖｅｒｏ细胞２０代（ＣＤＶ／Ｒ－２０）后又通过敏感犬的腹腔巨噬细胞，获得一株免疫原性更高的弱毒株（ＣＤＶ／Ｒ－２０／８）。接种同样剂量１０４ＴＣＩＤ５０的ＣＤＶ／Ｒ－２０／８和ＣＤＶ／Ｒ－２０的犬，产生出血清中和（ＳＮ）抗体价的几何平均数分别为１：５４和１：２６。前者为后者的２倍多。接种１０５ＴＣＩＤ５０的ＣＤＶ／Ｒ－２０／８能完全保护犬（１０／１０）抵抗ＣＤＶ强毒的攻击，接种１０４ＴＣＩＤ５０的保护９／１０犬，而对照犬５只全部发病，其中４只死亡。犬体内ＳＮ价可持续一年之久。冻干培养物在４和－３０℃中可分别保存９个月和１２个月而效力不减。     

VP_7-ELISA检测牛、羊血清蓝舌病抗体的研究Ⅱ应用VP_7-ELISA检测蓝舌病抗体

蓝舌病ＶＰ７抗原包被板在－２０℃保存期为６个月,４℃保存１个月。抗原批内重复性试验ＣＶ＜１０％,批间重复性试验ＣＶ＜１０％。ＶＰ７－ＥＬＩＳＡ与ＡＧＩＤ对４２０份血清平行检测结果：ＶＰ７－ＥＬＩＳＡ较ＡＧＩＤ试验多检出了 １３份阳性样品, ＶＰ,－ＥＬＩＳＡ检出的阳性样品对ＡＧＩＤ阳性样品的覆盖率为９７．４％,对采自陕西等省１８１６份牛、羊血清样品进行检测,检出阳性样品数为２５７份阳性检出率为１４．２％。     

VP7—ELISA检测牛,羊血清蓝舌病抗体的研究Ⅱ应用VP7—ELISA检 …

蓝舌病ＶＰ７抗原包被板在－２０℃保存期为６个月,４℃保存１个月。抗原批内重复性试验ＣＶ＜１０％,批间重复性试验ＣＶ＜１０％。ＶＰ７－ＥＬＩＳＡ与ＡＧＩＤ对４２０份血清平行检测结果：ＶＰ７－ＥＬＩＳＡ较ＡＧＩＤ试验多检出了１３份阳性样品,ＶＰ７－ＥＬＩＳＡ检出的阳性样品对ＡＧＩＤ阳性样品的覆盖率为９７．４％,对采自陕西等省１８１６份牛、羊血清样品进行检测,检出阳性样品数为２５７份,阳性检出率为１４．     

鸡传染性法氏囊病毒血清Ⅰ型和亚型混合弱毒疫苗研究初报

由美国ＩＢＤ血清Ⅰ型商品弱毒疫苗Ｂｕｒｓａ－Ｖａｃ，Ｕｎｉｖａｘ ＢＤ和中国广东的亚型弱毒疫苗ＣＮ９０３，ＣＳ９０４混合组成的弱毒疫苗，免疫剂量为１０００ＴＣＩＤ５０，对１２日龄无ＩＢＤ血清中和抗体或≤１：８的试验鸡，免疫试验结果表明，免疫后７天，能够产生９０－１００％的保护作用。ＩＢＤ混和弱毒疫苗保存在３４－３７℃１周，４－１０℃４周和－２５℃１２个月，疫苗的免疫保护率仍达１００％。对５个品种的     

鸡传染性法氏囊病病毒单克隆抗体的应用

通过中和试验证明，Ｂ３４腹水单克隆抗体中和ＩＢＤＶ ＣＡ株和中和效价高达１：４２００００。经１０倍稀释后，能等量中和含毒量为１０＾６．６２５ＴＣＩＤ５０／ｍｌ的ＩＢＤＶ ＣＡ株细胞毒。利用Ｂ３４腹水单克隆抗体建立了ＭＡｂ－ＡＣ－ＥＬＩＳＡ，可用于测定ＩＢＤＶ ＣＡ株细胞的病毒含量，与ＴＣＩＤ５０之间的相关系数为０．９４。     

鸡传染性法氏囊病Vero细胞弱毒疫苗免疫效果的研究

鸡传染性法氏囊病（ＩＢＤ）Ｖｅｒｏ细胞弱毒疫苗（ＶＣＶ９０１）病毒滴度为１０￣（７．３）～１０￣（８．３）ＴＣＩＤ＿（５０）／０．０５ｍｌ．疫苗经皮下、肌内、点眼－滴鼻和口服途径免疫接种雏鸡，均表现出良好的免疫原性。皮下接种１４日龄雏鸡，免疫后８、１４和２１天攻毒，保护数分别为２／６、６／６５／６，如在３５日龄再加强免疫一次，于二免后７０天和１１５天攻毒．其保护数分别为６／６和５／６．疫苗的最小免疫剂量为１０￣５ＴＣＩＤ＿（５０）／只，用１０、５０和１００培免疫剂量免疫雏鸡，临床表现均安全，不影响雏鸡增重．经易感雏鸡连传５代，疫苗毒力不返强．温苗在－２０℃～－２５℃至少保存一年，在０℃可保存一周，疫苗对鸡无致瘤性．     

鸡传染性支气管炎肾型弱毒株J9的免疫原性试验

以不同剂量（１０＾３．８￣１０＾４．９ＴＯＣＩＤ５０／只）的ＩＢ肾型弱毒株９免疫接种１５￣７０日龄ＳＰＦ鸡,然后用部分国内分离的ＩＢＶ肾型强毒株ＨＶ、ＮＢ９０、Ｌ－１、ＪＴ和国外肾型标准强毒株Ｔ攻击。三次试验初步表明,Ｊ９株具有对 强毒株攻击的不同程度的免疫保护作用。     

鸡病毒性关节炎弱毒疫苗的研制Ⅰ．弱毒株的筛选及其对雏鸡的安全性

将鸡病毒性关节炎病毒（ＡＶＡＶ）鸡胚毒Ｊ─１株适应于鸡胚细胞和Ｖｅｒｏ细胞，经连续传代，通过４０．５℃、３７℃、３２℃的交替升降培养温度培养，筛选出１株毒力较弱的克隆株，该克隆株蚀斑大小为２．７～３．１ｍｍ。以１０５．７２５ＴＣＩＤ５０注射于１日龄敏感雏鸡的足掌皮下和以１０４．７２５～１０６．７２５ＴＣＩＤ５０注射于１日龄敏感雏鸡胸部肌肉内，对雏鸡无致病性。该克隆株在敏感雏鸡内连传３代，无毒力返强现象。这一结果表明，本试验筛选出的ＡＶＡＶ弱毒株对雏鸡具有良好的安全性和遗传稳定性。     

饲粮能量浓度对梅花鹿瘤胃消化代谢参数的影响

选用４ 头装置永久性瘤胃瘘管的成年梅花鹿，用３ 种含有不同能量浓度的精料补充料，按４ ×３ 不完全拉丁方试验设计，对瘤胃内ｐＨ 值、氨态氮（ＮＨ３ － Ｎ） 、三氯醋酸沉淀蛋白（ＴＣＡ－Ｐ） 和总挥发性脂肪酸（ＴＶＦＡ） 浓度进行了测定， 并研究了它们的动态变化规律以及ＶＦＡ 组分百分率。试验日粮精料部分以玉米面、豆饼等为主要原料，配制出能量浓度不同（ＧＥ：３ ．９５ 、４ ．０５ 、４ ．１５ Ｍｃａｌ／ｋｇ） ，含粗蛋白质（２０ ．９９ ％ ） 、钙（０ ．６７ ％ ） 、磷（０ ．４０ ％ ） 相同的三种精料；粗料为玉米青贮，自由采食，计量不限量。试验鹿为单圈舍饲，每日每头鹿供给精料１ ．７５ｋｇ ，分两次饲喂，自由饮水；每种饲粮预饲期１４ 天，采样期１０ 天。采用ＰＨｓ － ２９Ａ 型酸度计测定ｐＨ 值；采用岛津ＧＣ－ ９Ａ 型气相色谱仪测定ＴＶＦＡ 浓度及ＶＦＡ 各组分比例； 采用氧化镁直接蒸馏法测定ＮＨ３ － Ｎ 浓度； 用岛津ＵＶ－ ２４０ 型紫外分光光度计测定ＴＣＡ－ Ｐ 含量。试验结果表明，日粮能量浓度对瘤胃内ｐＨ 值、ＮＨ３ － Ｎ 浓度、ＴＶＦＡ 浓度没有显著的影响（Ｐ＞ ０ ．０５） ，而对玉米青贮采食量及ＴＣＡ－ Ｐ 浓度影响显著（Ｐ＜ ０ ．     

鸡病毒性关节炎弱毒疫苗的研制

将鸡病毒性关节炎病毒鸡胚毒Ｊ－１株适应于鸡胚细胞和Ｖｅｒｏ细胞，经连续传代，通过４０．５℃、３７℃的交替升降培养温度培养，筛选出１株毒力较弱的克隆株，该克隆株蚀斑大小为２．７－３．１ｍｍ，以１０＾５．７２５ＴＣＩＤ５０注射于１日龄敏感雏鸡的足掌皮下和以１０４．７２５－１０＾６．７２５ＴＣＩＤ５０注射于１日龄 敏感雏鸡胸部肌肉内，对雏鸡无致病性，该克隆株在敏感雏鸡内连传３代，无毒力返强现象。这一结果     

Antibody Response in a Group of Swine After Infection with Foot-and-Mouth Disease Virus

Virus-neutralizing antibody and immunity after infection with foot-and-mouth disease virus was studied for 128 days in a group of swine. Antibody first appeared at 3 days, rose to peak levels between 7-10 days, and regressed to a plateau by 28 days. After 28 days, there was little change in mean antibody titres.

An attempt to reinfect 10 swine at 28 days was not successful. At 128 days, the immune status of 4 convalescent swine neutralized more than 4 logarithms of virus in an in vivo titration. However, in another group of 5 convalescent swine, one developed vesicular lesions when exposed to infected swine.

Efforts to demonstrate latent virus in one pig 128 days after infection were not successful.

     

Biology of cestodes of domestic ducks and wild water birds

Life cycles of 16 cestode species of the families Hymenolepididae and Diploposthidae were studied in 52 ponds of the State Fishery in Bohemia and Moravia. The parasites were recovered from domestic ducks kept on the ponds and from wild birds, mostly of the genera Anas and Aythya, occurring in these water biotopes. Cestode larvae were found in 9 species of Copepoda (9669 out of 1 600 200 examined specimens, i. e. 0.6%) and 3 species of Ostracoda (500 out of 272 300 examined specimens, i. e. 0.18%). Five species of water snails serving as reservoir hosts harboured cysticercoids of 5 cestode species (680 out of 10 212 examined specimens, i. e. 6%). The studies of cestode life cycle under natural conditions were supplemented with 680 successful experiments with intermediate hosts and 179 successful experiments with definitive hosts. The development of larvae was related to the temperature and lasted approximately 13-20 days at 18-25 degrees C. The highest intensity of infection occurred incrustaceans under experimental conditions, a lower intensity was found in crustaceans from duck farms and the lowest in crustaceans from other parts of ponds (e. g., in the case of Fimbriaria fasciolaris in Copepoda, 37, 22 and 10 cysticercoids). The intermediate hosts infected with cestode larvae can live for 3-6 weeks (Copepoda) and 4-7 weeks (Ostracoda) and after invagination of cysticercoids for 20-25 days, on the average. The cysticercoids survive their hosts for 14-18 h at 4-6 degrees C, for 10-11 h at 12-14 degrees C, for 6-7 h at 18-20 degrees C and for 3-4 h at 24-26 degrees C. If they are swallowed by water snails at that time (dead crustaceans are a component of their food), they survive in their digestive tract even for two years (the longest period demonstrated experimentally) and after this time they are able to develop into an adult cestode in the definitive host. The infectivity of cysticercoids increases with their age. It is the lowest immediately after invagination (10-15%), during the stay of cysticercoids in crustaceans it gradually increases (30-60% on days 10-20 after invagination) and it is the highest in cysticercoids from snails (45-55% after 20-50 days in snails, 60-80% after 50-100 days in snails and 70-90% after more than 100 days in snails).     

Treatment of broiler litter with organic acids

Experiments for treatment of contaminated broiler litter with citric, tartaric and salicylic acids were performed. At days 2 and 6 after the treatment, pH values (using a pH-meter), the ammonia concentrations (titration with 0.1 N HCl) and the microbial cells counts were determined in both experimental and control specimens of litter. The cost of acidification of litter was also determined. Our studies showed that the treatment of the contaminated litter with 5 per cent citric acid, 4 per cent tartaric acid and 1.5 per cent salicylic acid created an acid medium with pH under 5.0 and thus reduced the microbial counts to 2.2 x 10(3)colony forming units per gram manure litter. The treatment reduced the content of ammonia in the litter and in the air under the hygienic limits, i.e. 25-50 ppm. The cost of acidification of litter with these organic acids amounted to 0.1 $ per bird and 1.5 $ per 15 birds on one square metre in a growth period of 50 days.     

Melengestrol acetate as a tool for inducing early ovulation in transitional mares

The efficacy of melengestrol acetate (MGA) to shorten the vernal transition of mares by synchronising and accelerating the first ovulation of the year after 60 days of phototherapy was determined by ultrasonographic monitoring. Sixteen mares in late transition were fed two doses of MGA (150 mg/mare/day and 100 mg/mare/day, respectively) for 10 days. A luteolytic dose of prostaglandin was administered to each mare one day after the end of MGA treatment. The presence and duration of oestrus, follicular growth, uterine oedema and presence of ovulation were monitored by ultrasonography and the cervical tone was evaluated by rectal palpation. Ovulation was detected in 87.5% of the mares treated with 150 mg MGA/mare/day for 10 days, and in 62.5% of the mares receiving 100 mg MGA/mare/day for 10 days. This was statistically different (P = 0.03) from the untreated control mares having an ovulation rate of 20%. Mares that received 150 mg MGA/day for 10 days had a mean treatment to ovulation interval of 13.1 +/- 5.97 days after the end of treatment, while mares that received 100 mg MGA/day for 10 days had a mean of 25.6 +/- 10.50 days (P = 0.01) to ovulation. These results suggest that MGA can be used for synchronising and hastening the first ovulation of the year in mares.     

Synthetic adrenocorticotropic hormone stimulation tests in healthy neonatal foals

BACKGROUND: Cosyntropin (adrenocorticotropic hormone [ACTH]) stimulation tests are used to evaluate adrenal function. Low-dose ACTH stimulation tests are the most accurate method for diagnosing relative adrenal insufficiency in critically ill humans but have not been evaluated in foals. HYPOTHESIS: Peak serum cortisol concentrations in healthy foals will not be significantly different after intravenous administration of 1, 10, 100, and 250 microg of cosyntropin. ANIMALS: 14 healthy neonatal foals, 3-4 days of age. METHODS: A randomized cross-over model was used in which cosyntropin (1, 10, 100, or 250 microg) was administered intravenously on days 3 and 4 of life. Blood samples were collected before and 30, 60, 90, 120, and 150 minutes after administration of cosyntropin for determination of serum cortisol concentration. RESULTS: Serum cortisol concentrations did not significantly increase after administration of 1 microg of cosyntropin. Cortisol concentration peaked 30 minutes after administration of 10 microg of cosyntropin and 90 minutes after 100 and 250 microg of cosyntropin. There was no relationship between cosyntropin dose and serum cortisol concentration at 30 minutes. Compared with the 10-microg dose, 100 and 250 microg of cosyntropin induced significantly greater cortisol concentrations at 90 minutes, at which point the 10-microg cosyntropin-dose cortisol values were indistinguishable from baseline. There was no significant difference in the area under the cortisol concentration curve between the 100- and 250-microg doses. No effect of day of testing or foal weight on peak cortisol concentration was detected. CONCLUSIONS AND CLINICAL IMPORTANCE: The results of this study suggest that 10- and 100-microg doses of cosyntropin would be appropriate for evaluating adrenal function in neonatal foals.     

Growth and infectivity assays of the Israeli vaccine strain of fowl poxvirus in chicken embryo fibroblasts

The Israeli vaccine strain of fowl poxvirus grows efficiently in chicken embryo fibroblasts but not in cell lines derived from monkey kidney or human fibroblasts. We developed two assays for the titration of the infectivity of this virus in secondary cultures of chicken embryo fibroblasts. The first is a focus assay, in which minimum essential medium and SeaKem ME agarose were used for the overlay media. Under these conditions, clear virus foci appeared after 5 days of incubation at 37 C. The second assay is a semiautomatic colorimetric test based on the ability of live cells in culture to reduce the yellow tetrazolium salt 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT; thiazolyl blue) to its formazan derivative. The reagent was added to infected chicken embryo fibroblasts in 96-well plates 10 days after infection. The formazan formed during 2 hr was extracted with dimethyl sulfoxide, and its absorbance was read by an automatic microplate spectrophotometer. A good correlation of the infectivity titers of the virus was obtained by the two methods.     

桑飞象生物学特性及防治的初步研究

在江苏省丰县首次发现桑飞象为害桑树,并酿成严重灾害.此虫一年一代,以幼虫在土中越冬;翌年3月下旬至4月上旬在3—10厘米土层内化蛹,蛹期12—17天;4月中、下旬成虫出土上树取食桑芽和叶片,交尾后2—7天产卵在枝顶及春季剪梢口下段等处,每头雌成虫产卵44—205粒,卵期15—19天;初孵幼虫入土取食植物.用50%辛硫磷1000倍液每亩喷雾150—200斤防治效果良好.     

A Preliminary Study of the Development of 19s and 7s Immunoglobulins in Sera of Two Sheep Vaccinated With Brucella Abortus, Strain 19

The pattern of antibody response to vaccination with Brucella abortus, strain 19, was studied in two sheep. Agglutinative activity was detected by the third and fifth days and complement - fixing activity by the fifth and seventh days post-vaccination.

Density gradient centrifugation and DEAE cellulose column chromatography showed the 19S antibody developed first, followed soon after by 7S antibody. The former had disappeared by the 25th day but the latter persisted longer in both sheep. A small amount of 19S antibody was detected in sheep 1 following a booster dose of vaccine but 7S antibody constituted the major secondary response.

The standard tube agglutination test was found to be more efficient than the complement-fixation test for titration of 19S antibody. An increase in the salt concentration to 10% in tube agglutination test rendered it more sensitive in demonstrating 7S antibody.

     

鸡传染性喉气管炎人工感染试验

为建立人工模拟自然感染途径诱发鸡传染性喉气管炎病理模型,本试验采用80日龄京粉鸡随机分成健康对照组和试验组,试验组又设10-4、10-5、10-6 3个不同稀释度的剂量组,每组20只,将鸡传染性喉气管炎病毒经口腔滴注到鸡喉气管内进行攻毒,观察攻毒结果并统计发病和死亡情况。结果表明,10-4攻毒剂量组发病时间为1～8 d,发病率100％,死亡率10％;10-5攻毒剂量组发病时间为2～8 d,发病率100％,死亡率５％;10-6攻毒剂量组发病时间为4～9 d,发病率90％,死亡率0％。各组鸡均表现张口呼吸,咳出带血黏液的临床症状,剖检后均可见气管粘膜肿胀、出血,其中10-5组比较典型。10-5组经喉气管内滴注可以引起鸡100％发病,潜伏期、临床症状和病理变化典型,并且与自然感染基本一致,可用作鸡传染性喉气管炎病理模型。     

一株水貂犬瘟热病毒的分离与鉴定

为寻找免疫失败的原因,有效防治犬瘟热的流行,对临床一水貂犬瘟热疑似病例,取其肝、脾、脑等组织研磨后接种Vero和BHK细胞分离病毒,并对分离毒株进行一系列鉴定。通过电镜观察,发现了大小约150 nm的副黏病毒样粒子。结果表明,分离株对鹅、鸡、小鼠、家兔、山羊、猪红细胞均无凝集性,该分离株的毒价TCID50为10-4.87;分离株病毒对乙醚、氯仿敏感,病毒的核酸型为RNA。经间接免疫荧光试验,接种病毒的BHK细胞出现特异性的亮绿色荧光。对分离株和对照毒株分别提取RNA进行RT-PCR扩增,最后得到与预期扩增片段(294 bp)相符的核酸电泳带,充分证明分离病毒为犬瘟热病毒。