Quality control performance in a provincial veterinary diagnostic microbiology laboratory system

A quality control exercise was carried out in a provincial laboratory system to assess the performance of nine bacteriology technologists working in six laboratories. A group of ten mock specimens were distributed to each participant. Identification of all organisms and antibiotic susceptibility testing of pathogens was requested. Of the 117 organisms distributed, 104 were correctly identified, five were incorrectly identified and eight were not reported. Overall less than 1% very major errors, less than 5% major errors and less than 10% minor errors were observed in the antibiotic susceptibility testing. Most frequent errors were associated with penicillins, aminoglycosides, polymyxin, tetracycline and fastidious organisms.     

Computer-assisted enzyme immunoassays and simplified immunofluorescence assays: applications for the diagnostic laboratory and the veterinarian's office

A computer-assisted enzyme-linked immunosorbent assay (ELISA) system, based on kinetics of the reaction between substrate and enzyme molecules, was developed for testing large numbers of sera in laboratory applications. Systematic and random errors associated with conventional ELISA technique were identified leading to results formulated on a statistically validated, objective, and standardized basis. In a parallel development, an inexpensive system for field and veterinary office applications contained many of the qualities of the computer-assisted ELISA. This system uses a fluorogenic indicator (rather than the enzyme-substrate interaction) in a rapid test (15 to 20 minutes' duration) which promises broad application in serodiagnosis.     

IBR and BVD control: the key to successful herd management

Control of IBR and BVD should be possible in Europe. Effective vaccines and reliable tools for monitoring are available. Systematic approach and strict implementation of control measures are essential. Voluntary or mandatory programs are ongoing on regional or national level in a lot of countries. Successful programs put pressure on surrounding regions/countries to initiate control program as well.     

Implementation of two-step vaccination in the control of bovine viral diarrhoea (BVD)

Bovine viral diarrhoea (BVD) control/eradication programmes based on the test and removal of persistently infected cattle without use of vaccination were first introduced by the Scandinavian countries in the early 1990s. Within the last 10 years the programmes have proven to be very successful and have served as a blueprint for several other European regions. However, in areas with high cattle densities, intense animal trade and high BVD prevalence this control approach is risky, because there is a high probability that herds, which have been cleared of persistently infected (PI) animals and have become partly or fully susceptible to reintroduction of the virus, will come in contact with a BVD virus (BVDV) infected animal. A combination of the test and removal strategy with subsequent systematic vaccination of cattle could overcome this problem. The goals of vaccination in such a programme is protection against reintroduction of BVDV into herds free from PI cattle and foetal protection of pregnant animals accidentally exposed to the virus. Two-step vaccination is based on the use of inactivated BVDV-1 vaccine for priming followed by a live attenuated vaccine booster 4 weeks later. The immune response elicited by such a vaccination scheme has proven to be long lasting and foetal infection after challenge with BVDV-1 and BVDV-2 was prevented in pregnant animals 5 months after vaccination. These findings suggest that the implementation of a two-step vaccination in the initial phase of control programmes in addition to test and removal of PI animals in areas with high cattle densities and endemic BVD is practical and efficacious.     

Looking for new approaches for the use of serology in the context of control programmes against pig salmonellosis

Most swine Salmonella national control programmes in Europe have been based on the categorization of herds according to risk levels based on serological results. However, none of the non‐Scandinavian countries have reported of any significant success on Salmonella infection reduction in fattening pigs or the number of human cases attributable to pigs or pork. The limited accuracy of the tests used, the small number of animals sampled and the likely lack of herd representativeness of the samples used could be major factors affecting the suitability of these programmes. Focusing on minimizing Salmonella shedding at slaughter appears more important to prevent human infections than focusing on detection of seropositive pigs/herds at this stage. This study assessed whether performing on‐farm serology may help to predict shedding at slaughter. Between 2010 and 2016, pigs from six cohorts from a Salmonella‐positive herd were bled at 30, 60 and 90 days on fattening and before slaughter, and faecal samples collected at slaughter. Serology on days 60, 90 and before slaughter predicted somewhat shedding at slaughter with no significant differences among them. Pigs with higher OD% values at these point times would have higher risk of shedding when arriving to slaughter. The probability of shedding for a pig sampled on day 90 and showing an OD% value of 10 was 43%, and the risk increased up to 65% if the OD% was 40. Concluding, on‐farm serology may help to determine to some extent the risk of Salmonella shedding at slaughter from seropositive fattening units, which would allow for prompt on‐farm and slaughter interventions to reduce the likelihood of slaughter contamination with Salmonella.     

Modelling and costing BVD outbreaks in beef herds

Results from an epidemiological model of an outbreak of Bovine Viral Diarrhoea (BVD) within a Scottish beef suckler herd are presented. These results concurred with field observations and encouraged us to fulfill the objective of providing an estimate of losses due to BVD to assist decision makers. Using the output from the model, estimates were made of losses associated with the outbreak. Without taking into account any financial premiums associated with disease-free status, the estimate of pound 37 (58) mean loss per cow per annum suggests that health schemes and vaccination should be of immediate financial interest to farmers and veterinary advisors.     

Isolation and identification of anaerobes in the veterinary diagnostic laboratory.

In a 1-year survey (1975 to 1976) of anaerobic bacteria recovered from diseased animals, anaerobes were as follows: Clostridium spp, 50%; gram-positive nonspore-forming anaerobic bacilli, 19%; gram-negative anaerobic bacilli, 19%; Actinomyces spp, 10%; and anaerobic cocci, 1%. Anaerobes were in approximately 61% of the specimens that were culturally positive for any bacteria. Approximately 25% of the specimens did not yield any bacteria (sterile specimens). The method for isolating and identifying anaerobes was based upon the use of reducible solid mediums and was specially designed for veterinary diagnostic laboratories. Emphasis was placed on the selection, collection, and transportation of specimens.     

Tuberculosis in goats: assessment of current in vivo cell-mediated and antibody-based diagnostic assays

Tuberculosis in goats, mainly caused by Mycobacterium bovis and M. caprae, is a zoonotic disease with implications for public health, as well as having an economic impact due to decreased goat production, increased mortality rates and costs of diagnosis. There is an increasing need for surveillance of tuberculosis-infected goat herds, particularly in countries that are not officially free of bovine tuberculosis, and goats sharing farms with cattle should be subjected to the official tuberculin test. In Spain, some regions have programmes for the control of tuberculosis in goats, applying the same diagnostic assays that are used for cattle. The objective of tuberculosis eradication in livestock requires adaptation of existing control strategies to include goats. As such, it is necessary to determine whether current diagnostic assays for tuberculosis in cattle will work as efficiently in the goat. This review provides an overview of current in vivo tools for diagnosis of caprine tuberculosis, including estimates of the sensitivity and specificity of tests performed in this species. The number of tested animals and co-infection with Mycobacterium avium subsp. paratuberculosis are also addressed, with the aim of demonstrating the limitations of current assays and the need for further research.     

Surveillance and monitoring programmes in the control of rinderpest: A review

Tropical Animal Health and Production -     

西门塔尔牛BVD预防和治疗试验

肉牛的呼吸道疾病(BVD)多因运输应激而引起的一种顽固性疾病,常因临床治疗效果不佳,饲养成本增加。为降低本病给牧场造成 损失,自2020 年03 月26 日起,针对华润集团开鲁隔离场 牧场购自伊胡塔交易市场的西门塔尔品种架子牛,使用德国勃林格公司育肥牛到场操作流程方案进行应激处理并跟踪各项数据,与单纯使用勃林格公司驱虫药害获灭做对比评估,通过药物成本、死淘情况、增重指标的对比来评估方案优劣及成本核算分析,结果显示：(1)同样品种的西门塔尔育肥牛,在采购进入育肥场前后,进行不同应激处理方案,相比较只做害获灭+FMD 疫苗处理的牛群,使用专克灵+害获灭+FMD 疫苗处理的牛群,平均每头牛的日增重差别可以达到0.3kg/d,根据目前市场行情条件下,育肥牛销售约32 元/kg 的价格,在入场30 日内,平均每头牛可以多获得239.6 元的更多增重育肥收入;(2)在入场后使用专克灵预防BRD,配合害获灭驱虫,相比较入场后只做驱虫处理,能获得更低的BRD 发病率(低28.7%),发病牛更短的治疗天数(少0.5 d),更佳的平均日增重(多300 g),能够带来更好的增重收益;(3)实验组与对照组差别为0.3kg即平均日增重差别300g 。该数据可以直观的说明,入场时,是否全群专克灵处理牛群,预防BRD,对于后续日增重的影响,差异极其明显。本试验为华润集团隔离场领导及牧场技术人员参考。