Fetal deformities detected during surveillance for Schmallenberg virus

Congenital abnormalities detected in bovine fetal submissions Nematodirus infection diagnosed with varying clinical presentations in lambs by several centres Lungworm diagnosed as contributing to mixed respiratory disease in outdoor pigs Avibacterium paragallinarum (infectious coryza) infection detected in two flocks Haemonchosis diagnosed in adult alpacas from several farms These are among matters discussed in the Animal Health and Veterinary Laboratories Agency's (AHVLA's) disease surveillance report for April and May.     

Focal symmetrical encephalomalacia in young calves

Three cases of focal symmetrical encephalomalacia diagnosed in calves Diffuse fibrosing alveolitis diagnosed in an adult cow Review of abortion in sheep Erysipelas septicaemia in outdoor-reared piglets Fine sawdust bedding associated with pneumonia in layer chicks These are among matters discussed in the disease surveillance report for May from SAC Consulting: Veterinary Services (SAC C VS).     

Trends in bovine viral diarrhoea in Scottish cattle

Review of bovine viral diarrhoea virus-related disease, 1996 to 2009. Diverse range of respiratory diseases diagnosed in cattle. Caseous lymphadenitis confirmed in a Suffolk ram lamb aged only four months. Extramedullary haematopoiesis of unknown cause in a pig. Coccidiosis diagnosed frequently in pheasants and partridges. These are among matters discussed in the disease surveillance report for July from SAC Consulting: Veterinary Services (SAC C VS).     

First Isolation of a Rabid Bat Infected with European Bat Lyssavirus in Luxembourg

Rabid bats are regularly reported in Europe, especially in countries that have implemented a bat surveillance network. In May 2013, bat rabies was evidenced for the first time in Luxembourg (southern city of Differdange). The rabies virus, an EBLV‐1b strain, was diagnosed in a serotine bat that bit a 29‐year‐old male person while he was asleep. The man received rapidly a post‐exposure RABV treatment and was put under strict medical supervision.     

Eradication of Aujeszky's disease from New Zealand pig herds 1976-1997.

Aujeszky's disease was first diagnosed in the North Island of New Zealand in 1976. It has never been reported in the South Island. An industry-funded eradication programme was initiated in 1989 to eradicate the disease from the national pig herd. By using a combination of serological surveys, abattoir surveillance, test and slaughter, depopulation, vaccination and movement restrictions, Aujeszky's disease was eradicated by 1997.     

Distribution of equine infectious anemia in equids in southeastern United States

State veterinarians in 11 southeastern states completed a questionnaire designed to determine the proportion of equids in the region that were seropositive for equine infectious anemia (EIA). Cases of EIA were diagnosed in each of the states surveyed. Distinct geographic clusters of cases were apparent in Tennessee and Kentucky adjacent to the Mississippi River, in the Piedmont of North Carolina at the Virginia border, in north central Georgia, and throughout the Florida peninsula. It is suggested that the national EIA program could be improved by standardization and wider application of uniform active surveillance measures, and improved documentation of EIA status of horses on acquisition and transfer records.     

Community-based active surveillance for rabies in Machakos District, Kenya

The rabies problem in Kenya has been greatest in Machakos District where the disease has persisted endemically for over 40 years. This paper presents the results of a one-year community-based active surveillance for rabies in six randomly selected sublocations in the district for the period 1992-1993. Approximately 860 rabid dogs per 100000 dogs were confirmed in this study, compared to approximately 12 per 100000 confirmed rabid dogs reported by the existing passive-surveillance system. This active surveillance underestimated the true rabies incidence, because only 41% (130/317) of the potential specimens could be diagnosed. Dogs accounted for 92% (179/194) of primary animal-rabies suspects, 80% (66/83) of secondary suspects, and 81% of the confirmed animal-rabies cases. The annual incidence of animal-bites of humans was 234 per 100000 people and the point estimate of human-rabies incidence per year was 25 per million people. Almost all (97%) animal-bites of humans were due to dogs.The traditional passive-surveillance system grossly underestimated the importance of rabies as a public-health problem in Machakos District. Community-based active surveillance provides a potential cost-effective strategy for greatly improving estimates of rabies incidence and epidemiology to inform veterinary and policy decision-making.     

Antimicrobial therapy of selected diseases in turkeys,laying hens,and minor poultry species in Canada

This paper identifies common poultry diseases requiring antimicrobial therapy, antimicrobials deemed efficacious to treat these diseases, and antimicrobial resistance (AMR) in these commodity-pathogen combinations, and describes current residue issues and minor use minor species (MUMS) guidelines. Veterinarians with turkey/layer expertise and diagnosticians were surveyed to determine the bacterial and protozoal diseases diagnosed in the last 5 years. Avian pathogenic Escherichia coli, Staphylococcus aureus, and Ornithobacterium rhinotracheale were the 3 most frequently diagnosed pathogens of turkeys. In layers, E. coli-peritonitis, and Clostridium perfringens/Eimeria spp. infections were the most common diagnoses. A literature review identified 32 antimicrobials as efficacious and/or recommended for treating these diseases. Surveillance and monitoring indicate the presence of enteric resistant organisms from some of these avian species (including resistance to antimicrobials of very high importance to human medicine). This paper highlights the need for surveillance of pathogen frequency, antimicrobial use (AMU), and AMR particularly in turkeys.     

Ten years of BSE in Switzerland. The development of an extraordinary disease

The first case of bovine spongiform encephalopathy (BSE) in Switzerland was diagnosed in November 1990. BSE is--in particular considering its eradication--different from many other livestock diseases. Strict disease control measures were taken from the very beginning by the Swiss authorities in order to protect public as well as animal health. In addition, BSE has stimulated enormous media interest and public concern. The occurrence of the born after the ban (BAB) cases, increasing questions about the zoonotic potential of the disease and trade restrictions against Switzerland led to the "BSE-crisis". In 1999, Switzerland internationally took a leading role in the surveillance of BSE by active investigation of targeted risk population.     

Evaluation of surveillance strategies for bovine brucellosis in Japan using a simulation model

Bovine brucellosis is caused by Brucella abortus and induces abortions in female cattle, with other cattle at risk of infection from the aborted fetus or contaminated placenta. In Japan, the number of cases has dramatically reduced due to national surveillance and eradication strategies. Bovine brucellosis is now believed to be eradicated in Japan. Here, we examine the surveillance strategies currently in place for early detection of infected cattle in the event of a future reintroduction of the disease. We compared current serological surveillance for the dairy population with bulk-milk surveillance and abortion surveillance, and used time to detection as the main criterion of surveillance efficacy. A stochastic individual-based model (IBM) was developed to simulate disease transmission within and between farms. Using outputs from the transmission model, a comparison of surveillance strategies was simulated. For evaluation of the robustness of the parameter values used in the transmission model, a sensitivity analysis was conducted. For the purpose of evaluating the direct costs of each surveillance strategy, the annual number of samples to be tested and the annual number of farms to be visited were estimated. Our results indicated that current serological surveillance with 60-month test intervals is not effective enough for rapid detection of a brucellosis outbreak. Bulk-milk surveillance appeared the most effective method based on the early detection of infected cows and a reduced number of samples required. The time to detection for abortion surveillance was greater than that of bulk-milk surveillance but varied widely depending on the reported ratio of abortions. Results from the surveillance model were consistent when alternative scenarios were applied to the transmission model. Although our model cannot exactly replicate an actual brucellosis outbreak, or the results of surveillance, our results may help decision-makers to choose the most effective surveillance strategy.     

Spatial distribution of bluetongue surveillance and cases in Switzerland

Swiss Bluetongue surveillance from mid 2007 to mid 2008 was a combination of monthly bulk milk testing of 200 cattle herds in zones of higher risk for vector presence and intensification of passive clinical surveillance. The spatial scan statistic and Moran's I statistic were used to determine clustering of surveillance data. The results show a high level of surveillance intensity for BT in Switzerland in 2007. In the region encompassing the Cantons of Aargau, Basel-Landschaft, Basel-Stadt and Solothurn, where cases were detected in 2007, the surveillance was significantly higher than in the rest of Switzerland. Six cases of Bluetongue were detected within the surveillance system. The prevalence estimates 9.62% (95% CI = 3.25%-18.85% versus 0.98% (95% CI = 0.2%-2.22%) were also significantly higher in the area with higher surveillance intensity. Spatial variation in surveillance data should to be considered if a disease event is analysed on a national scale. The spatial variation of prevalence estimates should be considered in future Bluetongue surveillance in Switzerland.     

An evaluation of scrapie surveillance in the United States

Animal health surveillance systems should reflect national disease control priorities and promote the best use of public resources by maximizing effectiveness and efficiency. A surveillance system should be routinely evaluated to assess the degree to which the system accomplishes these goals, fulfills its stated objectives, and meets accepted surveillance standards. In the United States, there are a number of disparate endemic disease surveillance and eradication programs. The National Animal Health Surveillance System is a federal initiative designed to combine animal health surveillance and monitoring activities into a comprehensive and coordinated system. A protocol has been developed to facilitate the evaluation of animal health surveillance systems and investigate opportunities for coordination between the different surveillance and eradication programs. The evaluation protocol was based largely on protocols developed for public health but adapted for the specific needs and goals of animal health surveillance. The evaluation process was designed to identify program strengths and areas for improvement and facilitate the system's adaptability to changing situations. The evaluation protocol was applied to the scrapie surveillance system in the United States; scrapie surveillance was found to be an important part of surveillance for transmissible spongiform encephalopathies. Results from the evaluation of sensitivity, sampling methods and representativeness are presented.     

Evaluation and optimization of surveillance systems for rare and emerging infectious diseases

Surveillance for rare and emerging infectious diseases poses a special challenge to veterinary services. Most emerging infectious diseases like bovine tuberculosis (bTB) are zoonoses, affecting both human and animal populations. Despite the low prevalence of such an emerging infectious disease at time of incursion, the surveillance system should be able to detect the presence of the disease as early as possible. Because passive surveillance is a relatively cost-effective and therefore commonly used process, it is the basic tool for infectious disease surveillance. Because of under-reporting in passive surveillance, cost-intensive active surveillance is often required to increase the sensitivity of the surveillance system. Using scenario tree modelling, the sensitivity of passive and active surveillance system components (SSC) can be quantified and an optimal, cost-effective surveillance system developed considering the contributions of each SSC. We illustrate this approach with the example of bTB surveillance in Switzerland where the surveillance system for bTB consists of meat inspection at the slaughterhouse (SLI), passive clinical surveillance on farm (CLIN) and human surveillance (HS). While the sensitivities for CLIN and HS were both negligible (<1%), SLI was assessed to be 55.6%. The scenario tree model showed that SLI is increasable up to 80.4% when the disease awareness of meat inspectors in Switzerland is enhanced. A hypothetical random survey (RS) was also compared with a targeted survey (TS) in high-risk strata of the cattle population, and the sensitivity of TS was 1.17-fold better than in RS but with 50% of the sample size.     

Mycobacterium bovis infection in a captive herd of Sika deer.

Infection with Mycobacterium bovis was diagnosed in a small privately owned herd of Sika deer. After postmortem examination of a deer with progressive pulmonary disease, diagnosis of infection with M bovis was confirmed by bacteriologic culture. The 2 remaining deer in this herd were euthanatized, necropsied, and confirmed to be infected with M bovis. Three cats in contact with the deer were also euthanatized and necropsied. One of these cats had lesions suggestive of mycobacterial infection in the colon and mesenteric lymph nodes. Infection of this cat with M bovis was not confirmed by bacterial culture. Mycobacteriosis, infrequently encountered in clinical veterinary practice, may be confused with disease caused by other infective agents or neoplasia. The zoonotic potential of these bacteria and a recent increase in human tuberculosis warrants continued surveillance of companion and food animal populations for mycobacterial infection.     

Lack of PrP(sc) immunostaining in intracranial ectopic lymphoid follicles in a sheep with concomitant non-suppurative encephalitis and Nor98-like atypical scrapie: a case report

During active surveillance for transmissible spongiform encephalopathies (TSEs) in sheep, an initial reactor was detected using a rapid test on a brain sample. Immunohistochemistry confirmed an atypical TSE presentation that closely resembled the previously described Nor98 cases. Sequencing of the prnp gene confirmed the ARQ/AHQ genotype with the L141F mutation at codon 141 associated with this phenotype. The head, including the brain and cranial lymphoid tissues, was sampled and examined thoroughly. Non-purulent encephalitis, with ectopic lymphoid follicle formation within the brain, was diagnosed concomitant to the TSE. When scrapie-associated prion protein (PrP(sc)) deposition was studied by immunohistochemistry there was a noticeable lack of lymphotropism. The distribution of PrP(sc) in the brain differed considerably from that of classical scrapie cases. Astrogliosis and microgliosis were demonstrated by histochemical procedures.     

Active surveillance of BSE in cattle in The Netherlands

Since January 2, 2001 a large-scale active surveillance programme for BSE started in the Netherlands in addition to the passive surveillance programme of cattle with clinical symptoms compatible with BSE. Based on decisions of the Council of European Ministers of Agriculture, the European Union launched an active surveillance system for BSE in cattle of 30 months and older. Until April 1, more than 100,000 head of cattle were tested in this scheme, including all cattle slaughtered and a large part of the cattle that died on the farm. Four animals were found positive in the active surveillance system and one cow from the passive surveillance tested positive for BSE during the first three months.     

Establishing a cost-effective national surveillance system for Bluetongue using scenario tree modelling

Vector-borne diseases pose a special challenge to veterinary authorities due to complex and time-consuming surveillance programs taking into account vector habitat. Using stochastic scenario tree modelling, each possible surveillance activity of a future surveillance system can be evaluated with regard to its sensitivity and the expected cost. The overall sensitivity of various potential surveillance systems, composed of different combinations of surveillance activities, is calculated and the proposed surveillance system is optimized with respect to the considered surveillance activities, the sensitivity and the cost. The objective of this project was to use stochastic scenario tree modelling in combination with a simple cost analysis in order to develop the national surveillance system for Bluetongue in Switzerland. This surveillance system was established due to the emerging outbreak of Bluetongue virus serotype 8 (BTV-8) in Northern Europe in 2006. Based on the modelling results, it was decided to implement an improved passive clinical surveillance in cattle and sheep through campaigns in order to increase disease awareness alongside a targeted bulk milk testing strategy in 200 dairy cattle herds located in high-risk areas. The estimated median probability of detection of cases (i.e. sensitivity) of the surveillance system in this combined approach was 96.4%. The evaluation of the prospective national surveillance system predicted that passive clinical surveillance in cattle would provide the highest probability to detect BTV-8 infected animals, followed by passive clinical surveillance in sheep and bulk milk testing of 200 dairy cattle farms in high-risk areas. This approach is also applicable in other countries and to other epidemic diseases.     

Monte Carlo simulation of surveillance strategies for scrapie in Norwegian sheep

Our aim was to compare the efficiency of different surveillance strategies for detecting scrapie-infected sheep flocks in the Norwegian population using simulation modelling.The dynamic Monte Carlo simulation model has the flock as the unit. The input parameters include properties of the sheep population (number of flocks, flock size, age distribution, reasons for culling, breeds, prion protein-allele distribution); properties of scrapie (genotype-dependent infection rate and incubation periods, and age- and genotype-dependent prevalence of scrapie); properties of the surveillance strategy (selection of sheep for examination, period in which infected sheep are detectable, and properties of the diagnostic tests). For simplification, the prion protein-alleles were grouped into three allele groups: VRQ, ARR, and ARQ' (ARQ' represents ARQ, ARH and AHQ).Through either abattoir surveillance or surveillance of fallen stock, 70% of the detected sheep (compared to 33% in the underlying population). The model output was sensitive to the susceptibility of infection for the genotype ARQ'/ARQ'. The effect was large for abattoir surveillance (increased susceptibility increased the efficiency of abattoir surveillance).     

Design and Results of an Intensive Monitoring Programme for Avian Influenza in Meat‐Type Turkey Flocks During Four Epidemics in Northern Italy

Surveillance programmes for low pathogenicity (LPAI) and high pathogenicity avian influenza (HPAI) infections in poultry are compulsory for EU Member States; yet, these programmes have rarely been evaluated. In Italy, following a 1999 HPAI epidemic, control measures, including vaccination and monitoring, were implemented in the densely populated poultry area (DPPA) where all epidemics in Italy have been concentrated. We evaluated the monitoring system for its capacity to detect outbreaks rapidly in meat‐type turkey flocks. The evaluation was performed in vaccination areas and high‐risk areas in the DPPA, in 2000–2005, during which four epidemics occurred. Serum samples and cloacal swabs were taken from vaccinated birds and unvaccinated (sentinel) birds. We compared the detection rate of active, passive and targeted surveillance, by vaccination status, using multinomial logistic regression. A total of 13 275 samplings for serological testing and 4889 samplings for virological testing were performed; 6315 production cycles of different bird species were tested. The outbreaks detection rate in meat‐type turkeys was 61% for active surveillance (n = 222/363 outbreaks), 32% for passive surveillance and 7% for targeted surveillance. The maximum likelihood predicted values for the detection rates differed by vaccination status: in unvaccinated flocks, it was 50% for active surveillance, 40% for passive surveillance and 10% for targeted surveillance, compared to respectively 79%, 17% and 4% for vaccinated flocks. Active surveillance seems to be most effective in detecting infection, especially when a vaccination programme is in place. This is the first evaluation of the effectiveness of different types of surveillance in monitoring LPAI infections in vaccinated poultry using field data.