Experiences with the eradication of the bovine herpes virus 1 in Lower Saxony

In this paper first the general cascade of animal disease eradication from the voluntary control programme up to culling of infected animals is described. Afterwards the development of the eradication of Bovine Herpes Virus in Lower Saxony is illustrated. Obvious the number of farms which are not eradicating decreases since the testing on BHV1 is obligate in Germany. In 2004 60% of the cattle holdings were free from BHV1. At least the measures which will be taken in Lower Saxony to increase the success of eradication are explained.     

Promoting farmer engagement and activity in the control of dairy cattle lameness

Many 'influencers' allied to the agricultural industry support farmers to implement management changes that affect animal welfare. Developing approaches to working with farmers that achieve both engagement and subsequently management changes is critical. As an example, the generation of action points and implementation of change to control dairy cattle lameness is reported and discussed here. Action plans were generated on farms receiving both lameness monitoring and intervention support (MS group; n=117) as part of a 3year intervention project. At the start of year 1, MS farmers received action planning advice from a veterinary surgeon, and then at the start of years 2 and 3, farmers generated their own lameness control action plans with facilitator support. Engagement was achieved with 114 MS farmers who generated 692 action points in total. Two hundred and sixteen of these resulted from veterinary advice and 476 were generated by the farmers with facilitator support. In terms of activity, MS farms implemented a mean of 8.22 changes per farm as compared to 6.77 on farms which only received annual lameness monitoring (MO group; n=72). While these levels of change were similar, fewer changes implemented on the MS farms (8.5%) were judged 'likely to increase the risk of lameness' compared to the MO farms (16.5%). Farmers generated substantial numbers of lameness control action points for their own farms aided by a facilitator and, crucially, veterinary or facilitator involvement reduced changes that were likely to compromise lameness control.     

Case control study to investigate risk factors for bovine neonatal pancytopenia (BNP) in young calves in southern Germany

A case control study on farm level was conducted at the Clinic for Ruminants, LMU Munich, to identify possible risk factors associated with the observed increase in numbers of calves showing clinical signs of Bovine Neonatal Pancytopenia (BNP) since 2006 in southern Germany. Interviews were conducted between August 2008 and June 2010. The characteristics of 56 dairy farms with at least one confirmed case of BNP (thrombocytopenia and leukocytopenia and/or typical findings in post-mortem examination and bone marrow histology) were compared with those of two sets of 50 control dairy farms each, with no history of BNP. The first set of 50 control farms was selected randomly from veterinary practices which had never observed a BNP case on the farms they serviced. The second set of 50 control farms was matched by the veterinary practices which had provided case farms. Two separate analyses were conducted: (1) case farms (n=56) vs. randomly selected control farms (n=50) and (2) case farms (n=56) vs. a matched set of control farms (n=50). All variables with p<0.2 in the univariable analysis were included in stepwise logistic regression models. In the first analysis, only the use of PregSure(?) BVD vaccine was positively associated with BNP with an odds ratio of 1292 (95% CI: 114-14707). In the second analysis, conditional logistic regression models did not converge, therefore non-conditional logistic regression models were conducted. In the non-conditional analysis five variables remained in the model, three of which were negatively associated with BNP: the use of vitamin E and selenium, the frequent use of mastitis tubes, and the use of stem growth regulators in grain production. The use of prophylactic measures (such as control of parasites or vaccination of calves against respiratory disease) was positively associated with BNP with an odds ratio of 14.3 as well as the use of PregSure(?) BVD vaccine with an odds ratio of 426 (95% CI: 20-9095).     

Risk factors for introduction of BHV1 into BHV1-free Dutch dairy farms: a case-control study

In May 1998, a compulsory eradication programme for BHV1 started in the Netherlands. In December 1999 approximately 24% of Dutch dairy farms were certified BHV1-free (Animal Health Service (AHS)). Ninety-three certified BHV1-free dairy farms participated in a cohort study that investigated the probability of introduction of infectious diseases. The probability of introduction of BHV1 was determined from March 1997 until April 1999. Ninety of these farms remained BHV1-free and could be used as control farms. From January 1997 until March 1998, BHV1 was introduced into 41 BHV1-free dairy farms in the Netherlands (case farms). Management data were collected for both cases and controls and were complete for 37 case farms and 82 control farms. For small data sets and for data in which both low and high frequencies were expected in the contingency tables, the asymptotic methods were unreliable. Our data set clearly resembled such a data set; the risk factors were rare events because the BHV1-free farms were closed farms on which few direct animal contacts occurred. Therefore, an exact stratified modelling approach was most suitable for the data. The study showed that dairy farms should prevent cattle from escaping or mingling with other cattle and that professional visitors should always wear protective farm clothing.     

Evaluation of the sampling plan for a Salmonella monitoring program for slaughter pigs

In the setting of the Salmonella monitoring programme of the Federal Republic of Germany the sampling plan does not take into account prevalences occuring in reality. Hence, in most farms the testing effort will increase. This particularly applies to pig farms up to 100 fatteners, for which the proportion of animals to be tested is too high. Besides, the threshold values determing the allocation to the three quality categories, less than 20%, 20-40%, and more than 40% Salmonella positive fatteners, are also chosen too high.     

Risk factors for the infection of Swiss goat herds with small ruminant lentivirus: a case-control study

In the mid-1980s, Switzerland started a programme to eradicate caprine arthritis-encephalitis - an infectious disease of goats caused by the small ruminant lentivirus (srlv). Since 1996, progress towards eradication has slowed down, owing to infections occurring on farms from which the infection had previously been eliminated. To investigate specific risk factors for these new infections and to improve the eradication programme, a case-control study was conducted. Cases consisted of farms that had been officially free of srlv for at least three consecutive years but on which at least one srlv-seropositive animal had been detected during the annual serological surveys of 2001 and 2002. On all the case and control farms where sheep were housed together with goats, a subset of sheep was screened for antibodies to srlv. Potential risk factors were analysed in a logistic regression model; the results indicated that close contact with srlv-seropositive sheep was highly correlated with seroconversion in srlv-seronegative goat herds (odds ratio=26.9), supporting the hypothesis that srlv can be transmitted between sheep and goats, and suggesting that the measures taken so far will not lead to the complete eradication of srlv from Switzerland within the next few years.     

BHV-1 eradication program in Bavaria: a marker-independent strategy

In Bavaria a BHV-1 eradication program was initiated in 1986 and was changed to a compulsory program in 1998. The eradication success increased progressively from < 50% in 1986 to 87% of the farms in 2002. BHV 1-free farms are controlled by bulk milk serology twice a year along with blood serology in animals that are negative but from herds where positive field virus infected animals are present. All serological tests are performed with an indirect ELISA test, all positive results are confirmed by a gB ELISA. Currently about 100.000 virus infected cattle are in Bavarian herds, approximately 80% of these animals are in heavily infected herds (> 10 infected animals). These herds comprise about 5% of all Bavarian herds. The eradication of the virus in these heavily infected herds is the most diifficult, whereas the prevention of new infections appears controllable. In this review current problems in BHV1 eradication are named and possible improvements are discussed.     

苏皖地区规模化鸡场禽白血病净化的初步研究

基于苏皖地区禽白血病(AL)流行病学调查结果,本研究参考国际AL净化方案,针对该病在苏皖地区的流行特点,选择代号为DYAH91和DYJS31的两个规模化地方品系鸡群开展了禽白血病净化初步研究。经过一个世代的净化更替,DYAH91鸡群p27抗原阳性率由14.4%下降到8.1%,p27抗体阳性率由3.4%下降到1.0%,A/B亚群抗体阳性率由5.7%下降到2.2%,病毒分离阳性率由3.1%下降到0.45%;DYJS31鸡群,p27抗原阳性率由40.7%下降到2.8%,p27抗体阳性率由18.7%下降到3.3%,A/B亚群抗体阳性率由10.2%下降到1.4%,J亚群抗体由1.7%下降到1.4%,病毒分离阳性率由4.1%下降为0。以上结果表明通过净化程序的实施,鸡群ALV阳性率显著下降,净化方案效果确实。     

Development of the Dutch Johne's disease control program supported by a simulation model

The development of a simulation model, "JohneSSim", was part of a research program aimed at designing a national Johne's disease control program for The Netherlands. Initially, the focus was mainly directed towards different compulsory "test-and-cull" strategies. However, the results from the JohneSSim model showed that eradication of Johne's disease based on such strategies would not be possible within 20 years and that it was also economically unattractive. However, improved calf management seemed to be more effective in reducing the prevalence within the same time period. Simulation of a strategy using an "ideal test" (80% sensitivity in all infected animals) showed a considerably faster decrease in prevalence. However, this strategy proved to be economically unattractive because of the high culling rate of (young) test-positive animals. The simulation model was also adapted to study beef cow herds. However, the results indicated that none of the strategies were able to reduce the mean true prevalence to almost zero for such herds. Only strategies based on "separation of calves and adult animals" proved to significantly reduce the prevalence but such a strategy is unpractical and uneconomic for Dutch beef cow herds. Due to this finding and the relative low number of Dutch beef cow farms, first priority has been given to the development of a Johne's disease control program for dairy farms. Based on the results of the "JohneSSim" model, the new national voluntary Johne's disease control program for dairy, Paratuberculosis Program Netherlands (PPN), started in September 2000. The PPN is based on a stepwise improvement of calf hygiene, with little dependency on "test and culling". The model results indicated that, if dairy farmers consistently carried out the necessary management adaptations, PPN considerably decreased prevalence and that it was economically more attractive than any previous plans.     

The seroprevalence of Actinobacillus pleuropneumoniae in Swiss pig breeding herds--a study with the ApxIV ELISA

At the end of the national eradication program for Enzootic Pneumonia (EP) and Porcine Actinobacillosis (APP) in Switzerland (2003), A. pleuropneumoniae serotype 2 is considered to have been eradicated. There is no current information about the distribution of the other serotypes available. The ApxIV ELISA detects antibodies against all serotypes of A. pleuropneumoniae, without cross-reaction with other bacterial species. The aim of this study was to achieve actual data concerning the seroprevalence of A. pleuropneumoniae in breeding-herds and to validate the ApxIV ELISA under field conditions, especially for the diagnosis of latently infected breeding-herds without clinical signs, and to achieve more information about the role of herd book farms for the spread of the infectious agent. A total of 2068 serum samples from 96 pig herds in Switzerland were examinated. Over half of the examinated herd book farms showed positive results in this ELISA. 93% of the breeding herds were positive. On single animal level sensitivity was 96% and specifity 100%. Herd sensitivity ranged between 67% and 99%. Herd specifity was 100%. The results show that the ApxIV ELISA is a valuable tool for the detection of latently infected herds.     

2021年山东省家禽养殖场生物安全水平问卷调查

为了解山东省家禽养殖场的生物安全水平,以问卷调查方式,对养殖场基本信息、场内区域划分、免疫接种、引种购进、消毒、饲养管理等问题展开调查。经预调查后,2021年6—7月在全省范围内开展本次调查。在全省16个地级市,采用随机抽样方式,每地级市抽检1~2个县(市、区);应用配额采样方式,在县市域内选取蛋鸡养殖场、肉鸡养殖场以及种禽场各1家。共收到有效问卷141份,分别来自12个地级市36个县(市、区),其中来自蛋鸡养殖场、肉鸡养殖场和种禽场占比分别为63.83%、26.95%和9.22%。所调查养殖场中,按照管理区、生产区、生活区进行区域划分的133家,一半以上的养殖场能做到每周至少消毒1次;137家养殖场有免疫计划,而无免疫计划的只有4家,包括蛋鸡场1家、肉鸡场3家。肉鸡场没有隔离场所的占比最高,达44.7%。106家养殖场对患病动物进行无害化处理。结果表明,所调查家禽养殖场在区域划分、区域管理、消毒管理、环境控制等生物安全方面都进行了相关的设计和应用,在一定程度上,能够起到预防致病因子侵入、阻挡病原微生物扩散的作用,但不同类型养殖场的生物安全水平并不均衡,因此养殖场需继续提高生物安全意识,逐步建立适用于本场的生物安全体系。     

Assessing economic and social pressure for the control of bovine viral diarrhoea virus

The objective of this paper is to present a preliminary assessment of variation in the economic impact of bovine viral diarrhoea virus (BVDV) at dairy farm level between a sample of nations within the EU and hence assess differences in pressure to respond to this disease that may be impeding progress in control and hence restricting collective benefits from healthier livestock. We used a questionnaire to obtain national average values of key epidemiological and economic parameters for a typical dairy farm from BVDV experts in the countries concerned. These parameters were converted into assessments of economic impact using a computer simulation model. Uncontrolled output losses for a BVDV-na?ve herd with virus introduced in year 1 of a 10-year epidemic represented 22, 7, 8, 5, 8 and 20% of the BVDV-free annuity for the UK, Northern Portugal, Holland, Norway, Italy and Germany, respectively. Differences between countries will be widened by differences in the risk of acquiring BVDV. These will be much reduced in countries, such as Norway that have a national BVDV eradication programme. Farmers in such countries can therefore justify spending much less on maintaining BVDV-free status than BVDV-free farms in other countries. This result illustrates the paradox that in countries where BVDV prevalence is high, farmers have least to gain from unilateral BVDV eradication because of the high cost of maintaining freedom from the disease. We discuss this issue in the light of increasing recognition at international level of the importance of BVDV control.     

Successful eradication of the European rabbit (Oryctolagus cuniculus) and house mouse (Mus musculus) from the island of Selvagem Grande (Macaronesian archipelago), in the Eastern Atlantic

The Portuguese island of Selvagem Grande (Great Salvage) in Macaronesia is an important seabird breeding station in the eastern Atlantic. Significant populations of Cory's shearwater Calonectris diomedea (Scopoli, 1769), Bulwer's petrel Bulweria bulweria (Jardine & Selby, 1828) and little shearwater Puffinus assimilis baroli (Bonaparte, 1857) are present, and white-faced storm-petrel Pelagodroma marina (Latham, 1790) and Madeiran storm-petrel Oceanodroma castro (Harcourt, 1851) populations are of global significance. Selvagem Grande also provides diverse habitats for an extensive flora, including 11 endemic species. The 270-ha island was also inhabited by two alien invasive mammals: the European rabbit Oryctolagus cuniculus (Linnaeus, 1758) and the house mouse Mus musculus (Linnaeus, 1758). Both are known to have had adverse impacts on breeding seabirds and island vegetation. In 2002, the Natural Park of Madeira conducted a program using brodifacoum bait formulations aimed at rabbit and mouse eradication. Approximately 17 000 individual baiting points were established on a 12.5 × 12.5 m grid. Baits were also applied by hand “seeding” on steep slopes and cliffs where bait stations could not be placed. Rabbits were removed after a month. However, mice persisted for considerably longer and strategic bait applications against them continued for a further six months. Subsequent assessments by trapping, bait takes and systematic observation of signs over three years, has confirmed the removal of both alien invasive species. This paper presents information on these operations, on measures adopted to mitigate adverse impacts of the eradication program on important vertebrate non-target species, including Berthelot's pipit Anthus berthelotii Bolle, 1862 and a species of gecko Tarentola bischoffi Joger, 1984 and on the initial response of the island's ecosystem to the eradication of rabbits and mice.     

Eradication of porcine sarcoptic mange within a health declared production model

The success of a large-scale eradication programme against sarcoptic mange was evaluated in piglet producing herds belonging to the health class LSO 2000. These farms are monitored to be free from sarcoptic mange, swine enzootic pneumoniae, swine dysentery and progressive atrophic rhinitis. The local veterinarians were instructed to eradicate sarcoptic mange from the herds by 2 ivermectin injections 14 days apart or 3 treatments with phoxim pour-on 6 days apart before the farms were able to join the health class. The study consisted of a questionnaire administered to the farmers, farm visits and follow-ups associated with the regular control of the health class. A questionnaire was sent to all of the 379 accepted farrowing farms. Altogether 323 farmers had initiated an eradication programme at least 7 months before the questionnaire was distributed and 96% of them believed that the mange eradication programme had been successful. In most of the successful herds (90%), the local veterinarian had treated the animals by the recommended methods, and the majority of the farmers (88%) had cleaned and sprayed the pens with insecticides on the days of treatment. Three out of the 7 unsuccessful farms had employed methods other than those recommended. Twenty-five herds were randomly selected for an intensified control. The rubbing index was < or = 0.1 in all herds visited, indicating freedom from mange. Sows or gilts, 15-20 animals per farm, were skin scraped and no Sarcoptes scabiei was found. The same animals were blood sampled and serum antibodies to S. scabiei were measured by an indirect ELISA. All except 1 farm had low optical density (OD) values in most of the samples. The owner of that farm had become uncertain about the mange status of the herd and had recently retreated all animals with acaricides. The number of complaints about mange in the finishing units buying health class feeder pigs was low. The study demonstrates that it is possible to run an eradication programme against sarcoptic mange, in which a large number of farmers together with their veterinarians participate. It is possible to eradicate mange not only at the herd but also at the population level. The ELISA test employed proved to be a possible tool to monitor the efficacy of mange-eradication programmes.     

Use of hyperimmune serum, vaccination, and certain management procedures for control of pseudorabies in swine

A program involving use of hyperimmune serum, vaccination, and certain management procedures for the control of pseudorabies was evaluated on several farms on which the disease was enzootic. Neonatal mortality and reproductive failures on farms utilizing the program were compared with death losses and reproductive failures on farms not utilizing the program. The reduction in preweaning mortality and reproductive failures between the treated and nontreated groups were 42.1% and 39.6%, respectively.     

Attempted eradication of methicillin-resistant staphylococcus aureus colonisation in horses on two farms

REASONS FOR PERFORMING STUDY: Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging equine and zoonotic pathogen. Infection control protocols can be used to control MRSA in human hospitals, but measures to eradicate MRSA on horse farms have not been evaluated. OBJECTIVES: To describe an MRSA eradication programme that was used to attempt to eliminate MRSA colonisation among horses and horse personnel on 2 equine farms. METHODS: Active surveillance cultures and infection control protocols were implemented on 2 farms with endemic MRSA. RESULTS: Active screening and strict implementation of infection control protocols resulted in a rapid decrease in number of colonised horses on both farms. The majority of horses eliminated MRSA without antimicrobial treatment. On one farm colonisation was eradicated, while only 2 (3%) colonised horses remained on the other farm at the end of the study. CONCLUSIONS: Although at this stage the benefit of eradication of MRSA from populations of horses and cost-benefit studies have not been established, this study illustrates that short-term eradication can be achieved with a policy of segregation, enhanced infection control precautions and repeated testing of groups of animals. POTENTIAL RELEVANCE: Infection control practices should form the basis of MRSA control. Antimicrobial therapy does not appear to be required for eradication of MRSA colonisation in horses and control of MRSA on farms. In appropriate circumstances, these methods may be useful for controlling the spread of this potentially serious pathogen.     

Incidence and control of CSF in wild boar in Europe

The possibility that Classical swine fever (CSF) persists in a wild boar population has been shown in some areas of France, Germany and Italy in recent years. Availability of susceptible animals and frequency of infectious contacts are major variables influencing disease evolution. In the European Union (EU) measures to control CSF in the wild boar are enforced in the framework of Council Directive 80/217/EEC, including eradication plans that must be enforced taking account of the local epidemiological situation. Oral vaccination experiments are being carried out in Germany, which have not led to final conclusions concerning the efficacy of vaccination in eradicating disease.     

Spatial relative risk mapping of pseudorabies-seropositive pig herds in an animal-dense region

This paper describes a new approach for spatial relative risk mapping as a tool for geographical risk assessment. The spatial epidemiological analysis is based on geographically referenced data about pseudorabies (Aujeszky's disease) virus infections at farm level in a region of high animal density in Germany at the beginning of the national eradication project. On the basis of serological findings 186 farms were classified as positive out of a total of 482 investigated farms listed in veterinary administrative registers. Geographical cluster analysis was used to identify two areas of high risk (RR = 2.4 and 3.3). Non-parametric density estimation was used to estimate the proportion of infected farms per square kilometre. Furthermore, the spatial relative risk function was approximated through the prevalence ratio defined by the ratio of the local prevalence and the overall prevalence of the farms outside the cluster regions. The corresponding approximated relative risk map indicates and quantifies a clear spatial pattern of disease frequency.     

Risk factors for clinical Salmonella enterica subsp. enterica serovar Typhimurium infection on Dutch dairy farms

Risk factors for outbreaks in 1999 of clinical Salmonella enterica subsp. enterica serovar Typhimurium infection on dairy farms were studied in a matched case-control study with 47 case farms and 47 control farms. All 47 case farms experienced a clinical outbreak of salmonellosis which was confirmed with a positive bacteriologic culture for serovar Typhimurium in one or more samples. Serovar Typhimurium phage type 401 and 506 (definitive type 104, DT104) were the most frequently isolated phage types (13 isolates). On most farms (66%), clinical signs were seen only among adult cows. The most frequently reported clinical signs were diarrhoea (in 92% of the farms) and depression (in 79% of the farms).Control farms were matched on region and had no history of salmonellosis. A questionnaire was used to collect data on case and control farms. The relationship between serovar Typhimurium status of the farm and possible risk factors was tested using conditional logistic regression. Significant factors in the final model were presence of cats on the farm (OR=0.06), purchase of manure (OR=21.5), feeding colostrum only from own dam (OR=0.08), a non-seasonal calving pattern (OR=25), unrestricted grazing of lactating cows (OR=0.07), and a high mean mowing percentage of pasture (OR=1.02).     

Control of bovine viral diarrhea/mucosal disease in the district of Kamenz on a voluntary basis--ways, successes, limitations

In 69 dairy and beef herds in the district of Kamenz, Saxony, with a total number of 21,783 and 89.6% of the district's cattle, a voluntary BVDV eradication protocol was implemented from 2000 to 2007. The aim was to achieve eradication as comprehensive as possible and to prepare the herds for the mandatory eradication program. Essential preconditions for the accreditation of a herd as "free of BVD virus" were the antigen test of all cattle and their offspring for 12 months including completeness check and a negative serological random sampling of young cattle. Mean eradication period of infected herds lasted 45.6 months, herd size, and the number of newly purchased cattle were found to have a significant influence. In five infected farms calf losses significantly decreased after termination of the eradication. further examination of the 126 antigen test positive animals from 15 herds resulted in 87 persistently infected (PI) and 15 transiently infected (TI) individuals, 24 animals missed the second test. Furthermore, out of the 87 PI's 30 individuals (34%) had antibodies against BVDV. Eight farms vaccinated their whole herd, seven only the young stock before first breeding, and 54 herds did not vaccinate, respectively. Concluding from this study, the epidemiological particularities of the farms should be taken in account. Testing of all cattle in a minimum of time including, official monitoring of immediate culling of PI's, immediate epidemiological research, and serological monitoring of the eradication process is necessary.