Immune function in pheasants experimentally infected with marble spleen disease virus.

Two experiments were conducted to evaluate the effect of marble spleen disease virus (MSDV) infection on the immune response of pheasants. In the first, 15 ring-necked pheasants were inoculated orally with cell-culture-propagated MSDV and 15 received saline (controls). On days 7, 21, and 35 postinoculation (PI), all birds received sheep erythrocytes intravenously. Hemagglutination titers to sheep erythrocytes were determined for serum samples collected weekly for 6 weeks. The virus-inoculated group had significantly (P less than 0.05) lower hemagglutination titers than the control group. In the second experiment, 30 pheasants were allotted into two groups as above. Whole blood was collected from each bird weekly for 5 weeks. The blood was cultured in microtiter plates with or without optimum concentrations of concanavalin A. Five of 10 MSDV-inoculated pheasants had significantly depressed T lymphocyte transformation on either day 7 or day 14 PI. Overall, the depression of T lymphocyte transformation was transient and mild.     

规模化猪场寄生虫病的药物控制措施

1　规模化猪场寄生虫病流行病学特点规模化猪场通常采用的是工厂化的全进全出制流水作业生产系统。饲料自己生产 ,畜舍环境良好 ,管理技术先进 ,养猪生产的经济效益显著提高。规模化养猪由于自身的饲养管理特点 ,与小农户、小规模饲养相比寄生虫病的发生特点发生了很大的变化。1 1　无明显季节性变化为了给猪群营造一个良好的生产环境 ,规模化猪场猪舍内的温度、湿度等一年四季变化较小。这为场内寄生虫的繁殖、传播克服了季节变化的障碍 ,寄生虫病的发生已无明显的季节性变化。冬季猪蛔虫卵的感染率与夏季猪疥螨的感染率都不见降低。寄生虫…     

The influence of age on the response of ring-necked pheasants to infection with marble spleen disease virus.

Ring-necked pheasants that were negative for maternal antibody against type II avian adenoviruses were orally inoculated with 5.0 x 10(2) tissues-culture-infective doses of marble spleen disease (MSD) virus at 1-week intervals through 6 weeks of age, and at 9 and 13 weeks of age. Groups of four virus-inoculated birds and two control birds were necropsied at 4, 6, 8, and 10 days postinoculation, and the spleens were evaluated for gross and microscopic lesions. No lesions consistent with MSD were present in birds inoculated at 1, 2, 3, or 4 weeks of age. A single bird in the group inoculated at 5 weeks of age had gross and microscopic lesions of MSD. Five birds in the group inoculated at 6 weeks of age had lesions of MSD. The patterns of lesion development in the 6-week-old birds were similar to those produced in the 9- and 13-week-old birds inoculated with MSD virus. The reason for the lack of gross or microscopic lesion development during the first 4 weeks of life is unknown.     

Pathogenesis of marble spleen disease in bursectomized and non-bursectomized ring-necked pheasants following oral inoculation with cell-culture-propagated virus.

Seventy-two 13-week-old ring-necked pheasants were inoculated orally with 5.0 x 10(2) tissue-culture infective dose (TCID) of cell-culture-propagated marble spleen disease virus. Inoculated birds exhibited neither mortality nor clinical disease. Gross and histologic lesions were typical of marble spleen disease. The mean splenic weight was significantly (P less than 0.02) higher in inoculated birds than in controls between 6 and 10 days postinoculation (PI). The histologic splenic lesions, which consisted of reticuloendothelial cell hyperplasia, intranuclear inclusions within reticuloendothelial cells, and lymphoid depletion, were most prominent between 6 and 10 days PI. In a second experiment, 1-day-old pheasants were chemically bursectomized by dosing birds with 1.2 mg cyclophosphamide on 3 consecutive days. At 7 weeks of age, 54 bursectomized birds were inoculated orally with 5.0 x 10(2) TCID of marble spleen disease virus. Gross and histologic lesions were detected in one of the inoculated pheasants, but the mean splenic weight was not significantly different from control birds at any time PI. These results are evidence of the role of the bursa of Fabricius in the pathogenesis of marble spleen disease.     

Pulmonary congestion and edema (marble spleen disease) of chickens produced by group II avian adenovirus

"Marble spleen disease" of chickens was diagnosed in 22-week-old chickens. Total mortality was 8.9%. Deaths occurred over a period of 2 months. Gross lesions included pulmonary congestion, splenomegaly, hepatomegaly, and congestion of egg follicles. Microscopic lesions included pulmonary congestion and edema, and reticuloendothelial cell hyperplasia of the spleen with concurrent white-pulp necrosis and lymphocyte depletion. The pulmonary lesions were of sufficient intensity to have caused the death of fatally affected birds. Many of the hyperplastic reticuloendothelial cells contained basophilic intranuclear inclusions similar to those that characterize hemorrhagic enteritis of turkeys, marble spleen disease of pheasants, and adenovirus group II splenomegaly of chickens. These characteristic lesions, plus serologic identification of the causal virus, indicate that "marble spleen disease" caused by avian group II adenovirus was affecting the flock under study. This appears to be the first report of death of chickens due to pulmonary congestion and edema caused by spontaneous infection with avian group II adenovirus.     

Lessons learned from a strangles outbreak on a large Standardbred farm

Streptococcus equi subspecies (ssp.) equi infection (strangles) remains one of the most frequently diagnosed and costly infectious diseases of horses. Large breeding herds, where a disease outbreak competes for personnel and financial resources needed for foaling management, present a special challenge for equine practitioners. A 15‐month outbreak involving 62 clinical cases of strangles occurred on a large Standardbred breeding farm (average population of 1400 horses). Sixteen asymptomatic horses were found to be PCR (polymerase chain reaction)‐positive for S. equi ssp. equi. During the outbreak, serological samples from 48 clinically normal horses were found to be seropositive for S. equi ssp. equi, confirming herd‐wide exposure. After several clinical cases of strangles had been diagnosed, an intranasal S. equi ssp. equi vaccine was administered to clinically normal horses (n = 558) considered to be at risk of exposure. Strangles complications included 7 fatalities (none in vaccinated horses) and 6 cases of purpura haemorrhagica (4 in vaccinated horses). Midway through the outbreak, injectable, sustained release ceftiofur crystalline free acid (CCFA), given as an initial dose followed by a second dose 4 days later, was used exclusively for systemic antimicrobial treatment of clinically affected and PCR‐positive horses. This antimicrobial regimen coincided with a reduction in disease incidence and eventual resolution of the outbreak. Two horses with persistent guttural pouch infection were endoscopically confirmed as carrier horses. The herd history demonstrated that a strangles outbreak will often result in asymptomatic carrier horses and that identification and treatment of these horses are necessary to eliminate long‐term sources of infection. Ceftiofur crystalline free acid was found to be a suitable antimicrobial due to its activity against S. equi ssp. equi and the efficiencies associated with twice parenteral dosing during a 10‐day treatment period. Occurrence of purpura in 4 vaccinated horses suggests that vaccination should be reserved for healthy seronegative horses and avoided during an active outbreak.     

An outbreak of avian urolithiasis on a large commercial egg farm

A significant outbreak of avian urolithiasis was observed on a large commercial egg farm. From the initial outbreak site (a single laying house), the incidence of urolithiasis slowly spread in the ensuing months to numerous other laying houses. Increasing mortality associated with urolithiasis commenced during late growout to early lay and then leveled off when egg production peaked. At the height of the outbreak, mortality was typically 0.5% per week; 75% of this mortality was due to urolithiasis. The clinical and pathologic features of this condition are described. Both infectious bronchitis virus (IBV) and fowl adenoviruses were isolated from organ homogenates of sampled birds. A clone of the IBV strain was found to induce nephritis in specific-pathogen-free white leghorns.     

规模养鸡场(户)免疫失败原因及防治措施

最近一段时期，有螳规模鸡场和饲养户虽然按照要求，每年针对鸡的日龄晶种及免疫程序接种疫苗，但还是不断发生传染病，给规模养鸡场（户）造成了很大的经济损失。本人根据最近工作和实际调查情况，谈一谈规模鸡场（户）免疫失败的丰要原因和防制措施。     

Chronic wasting disease in a Wisconsin white-tailed deer farm

In September 2002, chronic wasting disease (CWD), a prion disorder of captive and wild cervids, was diagnosed in a white-tailed deer (Odocoileus virginianus) from a captive farm in Wisconsin. The facility was subsequently quarantined, and in January 2006 the remaining 76 deer were depopulated. Sixty animals (79%) were found to be positive by immunohistochemical staining for the abnormal prion protein (PrP(CWD)) in at least one tissue; the prevalence of positive staining was high even in young deer. Although none of the deer displayed clinical signs suggestive of CWD at depopulation, 49 deer had considerable accumulation of the abnormal prion in the medulla at the level of the obex. Extraneural accumulation of the abnormal protein was observed in 59 deer, with accumulation in the retropharyngeal lymph node in 58 of 59 (98%), in the tonsil in 56 of 59 (95%), and in the rectal mucosal lymphoid tissue in 48 of 58 (83%). The retina was positive in 4 deer, all with marked accumulation of prion in the obex. One deer was considered positive for PrP(CWD) in the brain but not in the extraneural tissue, a novel observation in white-tailed deer. The infection rate in captive deer was 20-fold higher than in wild deer. Although weakly related to infection rates in extraneural tissues, prion genotype was strongly linked to progression of prion accumulation in the obex. Antemortem testing by biopsy of recto-anal mucosal-associated lymphoid tissue (or other peripheral lymphoid tissue) may be a useful adjunct to tonsil biopsy for surveillance in captive herds at risk for CWD infection.     

规模猪场合理的免疫程序

本简要介绍对规模猪场威胁较大的几种传染病及其它常见病疫（菌）苗的使用，供养猪生产制定免疫程序时参考。     

规模化猪场兽医的职责和任务

规模化猪场必须配备兽医人员 ,而兽医这个称号不是随便可以授予的 ,兽医需要具备一定的专业知识和相关的学历。规模化猪场的兽医工作十分重要 ,任务也很艰巨。猪场的兽医人员不仅要及时诊断和治疗病猪 ,还负有猪群的防疫、检疫重任 ,猪场的卫生安全体系建设、猪群的兽医卫生监督 ,都是兽医的职责。兽医又是一个执法者 ,应按国家有关政策、法规 ,监督、执行某些法定传染病的防制。提高猪场的兽医防疫水平 ,确保猪群的健康成长 ,是规模化猪场持续发展的必要条件 ,所以猪场领导应重视兽医人员的配备和培养 ,充分发挥兽医人员的作用 ,猪场兽医主…     

提高规模化猪场经济效益的技术措施

经济效益是衡量规模化养猪场投入与产出的一个尺度,如何以较少的人力、物力和财力投入,获得最佳的养猪经济效益,把猪群的饲养管理经济与饲料的营养经济措施科学地组合应用,是提高规模化养猪场经济效益的关键.     

某规模化猪场伪狂犬病抗体检测与分析

目的:为了掌握规模化猪场伪狂犬病野毒感染情况,减少伪狂犬病所造成的经济损失,以及规模化猪场应当采取的有效防疫措施。方法:采用ELISA法对某规模化猪场7~12月份的经产母猪和后备猪进行伪狂犬病抗体检测。结果:该猪场的伪狂犬病阳性率为21.26%,是伪狂犬病野毒阳性场。结论:该猪场在检测出伪狂犬病抗体呈阳性后,采取了一系列措施,从而控制了疫情的发生。