Epidemiology,zoonotic aspects,vaccination and control/eradication of brucellosis in India

In India, brucellosis was first recognised in 1942 and is now endemic throughout the country. The disease is reported in cattle, buffalo, sheep, goats, pigs, dogs and humans. B. abortus biotype-1 in cattle and buffaloes and B. melitensis biotype-1 in sheep, goats and man are the predominant infective biotypes. The long-term serological studies have indicated that 5% of cattle and 3% of buffaloes are infected with brucellosis. Economic losses due to brucellosis in livestock are considerable in an agrarian country like India. There is no organised and effective brucellosis control programme in the country. With the indigenous development of serum and milk based ELISA kits, the population survey of the disease has been undertaken on a large scale in several states and plans for the control of the disease through calf-hood vaccination are being worked out. An innovative approach—Bovine Brucellosis Progressive Control Programme (BBPCP) is targeted to overcome the basic problems of ban on cow slaughter, distress sale of animals following the positive serological diagnosis of brucellosis and absence of a disease control strategy. The work plan for the implementation of BBPCP is presented.     

Eradication of bovine brucellosis in the 10th Region de Los Lagos,Chile

The process of Bovine Brucellosis Eradication that began in 1996 in the 10th Region de Los Lagos of Chile will be reviewed. The region comprises the most important dairy area of the country and it has the largest concentration of brucellosis infected herds. Based on the information gathered by an epidemiological surveillance system, the results of the eradication process for the years 1996 till 2001 are presented as rates of Milk Ring Test (MRT) positive dairies, rates of brucellosis reactors (bovines) in livestock markets and slaughterhouses, and the annual incidence and prevalence of brucellosis infected herds.

During the period the rates of positive dairies, bovine reactors in livestock markets and slaughterhouses, and the annual incidence and prevalence of infected herds have experienced a decrease, while the rate of bovine reactors in slaughterhouses has remained stable. Data on the preventive measures taken, such as vaccination of female bovines and Certification of Brucellosis Free Herds, are also shown. The surveillance system has allowed the detection of infected herds, while the measures of prevention and cleaning of infected herds have allowed a reduction in the incidence and prevalence of the infection by Brucella abortus.     

低血容量性休克在传染性法氏囊病发生发展中的作用

本试验对实验性传染性法氏囊病（ＩＢＤ）患鸡的休克相关症候群做了动态检测,并观察了补液治疗对ＩＢＤ发病过程的影响。结果发现在ＩＢＤ发病过程中存在明显的休克相关症候群,补液治疗不仅能减轻休克的严重程度,而且还能降低患鸡的死亡率。此结果表明低血容量性休克在ＩＢＤ发生发展中起重要作用,并构成ＩＢＤ患鸡死亡的重要原因。     

鸡新城疫、传染性支气管炎病毒同胚接种试验

通过对五个批次的无特定病原体(SPF)鸡胚进行鸡新城疫病毒（NDV）、鸡传染性支气管炎病毒（IBV）同胚接种,收获72～120 h死胚及120 h活胚尿囊液,分别测定NDV和IBV的病毒含量,结果表明NDV病毒含量达到了108.3～108.7EID50/0.1mL, IBV的病毒含量达到了106.3～106.5EID50/0.1mL。两种病毒含量均达到《中华人民共和国兽用生物制品制造及检验规程》（2000版）中鸡新城疫、传染性支气管炎二联活疫苗病毒含量要求的标准。表明该方法即可降低成本,又简化了生产工艺。     

Epidemiological investigation of infectious salmon anaemia (ISA) outbreaks in Norway 2003-2005

Epidemiological information was summarized from 32 outbreaks of infectious salmon anaemia (ISA) on salmon farming sites in Norway in 2003–2005. Virus isolates from the outbreak sites were genotyped, and the genotyping was used to assess possible associations between outbreak sites due to adjacent location, sharing fish farming authorisation, sharing smolt suppliers or sharing broodfish origin of the fish. The ISA outbreaks were distributed along most of the Norwegian coast and showed a variable clinical picture. The virus genotypes clustered into three genogroups. Pairs of outbreak sites matched for adjacent location or registered under the same authorisation, all shared genogroup, which was a significantly higher number of corresponding genogroups than expected by chance. For outbreak sites sharing smolt suppliers, corresponding genogroups appeared in 7 out of 12 matched pairs, which was not significant. An evaluation of broodfish origin associated with genogroups did not support transmission linked to broodfish origin. In conclusion, genotyping of virus isolates from ISA outbreaks supports associations between adjacent outbreaks. This is consistent with horizontal transmission. The present study failed to find evidence for vertical transmission (patterns of genogroups related to smolt suppliers or broodfish companies were not identified).     

Evaluation of testing strategies for infectious salmon anaemia and implications for surveillance and control programs

Infectious salmon anaemia (ISA) is an economically important disease in New Brunswick, Canada. Current regulatory control involves detection of ISAv in broodstock, hatcheries and marine sites through a surveillance program. Prior to recent assessments of operating characteristics of diagnostic tests, the efficiency of this surveillance program was difficult to evaluate. In order to determine the optimal testing strategies for various phases of production, a cost-effectiveness analysis was done for different strategies including single testing and multiple testing with results interpreted in series or in parallel. The lowest cost testing strategy, which would achieve a group-level sensitivity (GSe) of 95% and a group-level specificity (GSp) of 95%, was determined for each production phase. Our analyses showed that the most cost-effective testing strategy depended on the production phase. If sampling is to be carried out in a freshwater facility, then broodstock should be tested by VI alone, while pre-smolts should be tested with IFAT and VI used in series. For fish reared in saltwater, parallel interpretation of results from VI and RT-PCR, or testing with VI alone, are appropriate testing strategies for broodstock. For market-fish, PCR alone is a good screening option. If one assumes the prevalence of ISAv in moribund fish is at least 50%, then a maximum of 5 fish (at a cut-point of 1 positive fish to designate a cage as positive) need to be tested at a cost of $220. If one desired to have a perfect GSp (i.e. no false positive cage designations), serial testing with IFAT and VI is a better option. However, for this strategy a maximum of 9 fish (at a cut-point of 1) need to be tested at a cost of $472.     

禽用病毒-抗体复合物疫苗研究进展

病毒-抗体复合物疫苗是将病毒的特异性抗体按照适当的比例与传染性病毒混合制成的一种新型疫苗.国内外研究者做了大量的相关研究,并且在鸡传染性法氏囊病、新城疫等禽病的复合物疫苗研究中取得了突破性进展,为禽病疫苗的研究及禽病的防控开辟了一条新的独特途径.文章就复合物疫苗研究近况进行简要阐述.     

传染性支气管炎病毒感染对雏鸡血清IFN-γ和IL-4的影响

[目的]探讨传染性支气管炎病毒（IBV）感染后雏鸡干扰素（γ）和白介素4（IL-4）的变化。[方法]将80只15日龄雏鸡随机分为对照组和试验组。试验组雏鸡滴鼻接种IBV尿囊液。分别于21、24、27日龄时,每组随机取10只鸡,ELISA方法测定血清IFN-γ和IL-4水平。[结果]IBV感染组雏鸡血清IFN-γ水平显著降低（P〈0.01）,IL-4水平显著上升（P〈0.01）。在24、27日龄IL-4水平在试验组和对照组之间差异极显著（P（0.01）。[结论]IBV感染雏鸡的细胞免疫和体液免疫处于紊乱态势。     

IBDV—MA5787人工感染雏鸡的病理学研究

为了揭示 IBDV-MA5787对雏鸡的致病性,本试验采用解剖学、组织学、电镜技术和血清学方法对28日龄雏鸡人工感染 IBDV-MA5787(内蒙株)后不同时期的病理学变化进行了观察,试验结果表明,IBDV 攻击的靶器官是法氏囊,首先引起法氏囊急性炎性水肿,而后发展为坏死性炎和网状内皮细胞增生。另外也引起睥、盲肠扁桃体、胸腺、肝、肾和心脏等器官组织细胞变性和坏死。该病毒主要损害体液免疫。内蒙毒株毒力较强。     

Prevalence of bovine herpesvirus-1 in the Belgian cattle population

The national bovine herpesvirus 1 (BHV-1) seroprevalence (apparent prevalence) in the Belgian cattle population was determined by a serological survey that was conducted from December 1997 to March 1998. In a random sample of herds (N=556), all cattle (N=28 478) were tested for the presence of antibodies to glycoprotein B of BHV-1. No differentiation could be made between vaccinated and infected animals, because the exclusive use of marker vaccines was imposed by law only in 1997 by the Belgian Veterinary Authorities. Twenty-one percent of the farmers vaccinated continuously against BHV-1.

In the unvaccinated group, the overall herd, individual-animal and median within-herd seroprevalences were estimated to be 67% (95% confidence interval (CI)=62–72), 35.9% (95% CI=35.0–36.8) and 33% (quartiles=14–62), respectively.

Assuming a test sensitivity and specificity of 99 and 99.7%, respectively, the true herd, individual-animal and median within-herd prevalence for the unvaccinated group of herds were estimated to be 65, 36 and 34%, respectively. The true herd prevalence for dairy, mixed and beef herds were respectively, 84, 89 and 53%; the true individual-animal prevalence for those types of herds were, respectively, 35, 43 and 31%; whereas, the true median within-herd prevalences were 36, 29 and 38%.