Development of methodology to prioritise wildlife pathogens for surveillance

We developed and evaluated a methodology to prioritise pathogens for a wildlife disease surveillance strategy in New Zealand. The methodology, termed 'rapid risk analysis' was based on the import risk analysis framework recommended by the Office Internationale des Epizooties (OIE), and involved: hazard identification, risk estimation, and ranking of 48 exotic and 34 endemic wildlife pathogens. The risk assessment was more rapid than a full quantitative assessment through the use of a semi-quantitative approach to score pathogens for probability of entry to NZ (release assessment), likelihood of spread (exposure assessment) and consequences in free-living wildlife, captive wildlife, humans, livestock and companion animals. Risk was estimated by multiplying the scores for the probability of entry to New Zealand by the likelihood of spread by the consequences for free-living wildlife, humans and livestock. The rapid risk analysis methodology produced scores that were sufficiently differentiated between pathogens to be useful for ranking them on the basis of risk. Ranking pathogens on the basis of the risk estimate for each population sector provided an opportunity to identify the priorities within each sector alone thus avoiding value-laden comparisons between sectors. Ranking pathogens across all three population sectors by summing the risk estimate for each sector provided a comparison of total risk which may be useful for resource allocation decisions at national level. Ranking pathogens within each wildlife taxonomic group using the total risk estimate was most useful for developing specific surveillance strategies for each group.     

Risk assessment of foodborne infections

The microbiological risk assessment during production, processing and treatment of foods illustrates an important basis for the judgement of the safety of food products. Since the mid-nineties the concept of risk analysis according to Codex Alimentarius requirements ist pursued more intensely. Risk assessment is part of the risk analysis process besides risk management and risk communication. A strict separation between risk management and assessment should lead to a systematic, scientifically based and independent process without considering economic or political constraints whereas the decision on protective measures or the acceptance of risks lies in the responsibility of the managers. Risk assessment can only be successfully implemented in an interdisciplinary approach between physicians, veterinarians, microbiologists, molecularbiologists, food technologists, epidemiologists and mathematicians. Surveillance, monitoring programs and other data collections on a variety of parameters like statistics on foodborne human cases, the prevalence of zoonotic agents in animals, the distribution of micro-organisms in the environment and in foods, the behaviour of micro-organisms during food processing and the consumption habits of consumers deliver the necessary data for risk assessors. With the aim of mathematic modelling and simulation it is possible to calculate the probability of health problems in humans after the consumption of a foodstuff contaminated with a specific pathogenic micro-organism.     

A Qualitative Risk Assessment Approach for Swiss Dairy Products: Opportunities and Limitations

Switzerland implemented a risk‐based monitoring of Swiss dairy products in 2002 based on a risk assessment (RA) that considered the probability of exceeding a microbiological limit value set by law. A new RA was launched in 2007 to review and further develop the previous assessment, and to make recommendations for future risk‐based monitoring according to current risks. The resulting qualitative RA was designed to ascertain the risk to human health from the consumption of Swiss dairy products. The products and microbial hazards to be considered in the RA were determined based on a risk profile. The hazards included Campylobacter spp., Listeria monocytogenes, Salmonella spp., Shiga toxin‐producing Escherichia coli, coagulase‐positive staphylococci and Staphylococcus aureus enterotoxin. The release assessment considered the prevalence of the hazards in bulk milk samples, the influence of the process parameters on the microorganisms, and the influence of the type of dairy. The exposure assessment was linked to the production volume. An overall probability was estimated combining the probabilities of release and exposure for each combination of hazard, dairy product and type of dairy. This overall probability represents the likelihood of a product from a certain type of dairy exceeding the microbiological limit value and being passed on to the consumer. The consequences could not be fully assessed due to lack of detailed information on the number of disease cases caused by the consumption of dairy products. The results were expressed as a ranking of overall probabilities. Finally, recommendations for the design of the risk‐based monitoring programme and for filling the identified data gaps were given. The aims of this work were (i) to present the qualitative RA approach for Swiss dairy products, which could be adapted to other settings and (ii) to discuss the opportunities and limitations of the qualitative method.     

Import risk analysis in animal disease control

At the Swiss Federal Veterinary Office risk analyses are conducted according to international standards. A risk analysis contains the elements risk management, risk assessment and risk communication. A risk assessment is based on risk profile, hazard identification and a pathway model. All available information is gathered, documented and assessed and the risk estimated. The question. "What is the probability that unprocessed wild boar meat imported to Switzerland from the federal state Mecklenburg Western Pommerania is contaminated with classical swine fever virus?" was answered by a release assessment. The hazard identification recognized classical swine fever virus and attenuated live virus vaccine used for oral immunization as hazards. The probability of contamination was estimated to be small. The question: "What is the likelihood to introduce Aujeszky's disease to Switzerland and infect the indigenous pig population with the disease, by means of importing pork and meat products?" was answered by assessing the release, exposure and resulting consequences. The risk of an infection of the indigenous pig population was estimated to be very small, as 80% of the imported products derive from countries or zones free from Aujeszky's disease. Furthermore the majority of the imported products are processed. The strict implementation of the regulations governing feeding of food wastes to pigs reduces the probability of exposure. In all assessments the risk management decides on a strategy to deal with the risk, taking into consideration the results and recommendations derived from the risk assessment as well as other relevant factors.     

中国猪瘟发生风险定性评估

为定性评估中国猪瘟发生风险,本研究通过收集整理国内外猪瘟研究资料,运用动物疫病风险分析方法对猪瘟病原特性、传染源、传播途径、易感动物和已采取防控措施效果5个主要风险因素进行定性分析。风险评估认为目前全国范围均存在猪瘟发生风险,由于实施了猪瘟强制免疫政策,猪群均存在一定的免疫抗体,因此猪瘟大规模流行几率很低,但点状散发流行几率较高。现阶段疫苗免疫仍是中国防控猪瘟的重要手段。     

兽用基因工程生物制品的安全控制对策与措施( II )——生物安全性评价

本文阐述了与兽用基因工程生物制品的生物安全性评价有关的动物病原体的危害性分类与生物安全等级、安全性评价的内容和要求及制品的安全性复核检验等内容     

Stakeholder position paper: the need for antimicrobial use data for risk assessment

Risk assessment seeks to estimate the probability and impact of human health effects due to antimicrobial resistance arising from antimicrobial use in animals. Potential ecological pathways for the flow of antimicrobial resistant bacteria and resistance determinants through the food supply and environment are diverse and complicated and this has been a logistical barrier to direct epidemiological measure of risk. Consequently, a number of indirect approaches to assessment have been developed. This paper provides some examples of risk assessments that have been conducted with and without antimicrobial use data, and identifies possible benefits and applications of quantitative antimicrobial use data for risk assessment.     

Conceptual foundations for infectious disease surveillance.

The purpose of this report is to offer concepts for consideration in developing infectious disease surveillance systems, defined here as active, formal, and systematic processes intentionally directed to rapidly seek out and identify infectious disease agents or disease. Performance of surveillance systems can be judged by their accuracy (sensitivity and specificity), precision (repeatability), timeliness, multiple utility, and value. Surveillance system operation and function necessary to achieve high performance are defined in part by characteristics of the specific infectious disease, including disease transition state dynamics, that define probabilities of being in the latent, infectious, or clinical phase of disease. Two key components of surveillance are the sampling scheme, which is intended to maximize the probability of capturing an infected animal or specimen as soon as possible after the herd has been exposed, and the diagnostic assays, which should maximize the probability of detecting the agent, or evidence of the agent, if it is present in the specimen, while minimizing the likelihood of a false-positive result. Proportional risk sampling, targeted sampling, and repeated sampling are strategies that can improve overall surveillance system accuracy and particularly the temporal sensitivity related to early detection. Hierarchical sampling schemes and multiplexed assays can maximize efficiency and improve utility by serving multiple surveillance systems and purposes. Development of the surveillance systems needed to address emerging and foreign animal diseases will necessarily require design and architecture that are highly probability-driven to maximize surveillance sensitivity and specificity and to minimize cost.     

Food safety in the future: genes, molecular mechanisms and test systems

The idenfication of the human genome makes it possible to investigate complex biological issues with new molecular techniques. Platformtechnologies such as DNA-Arrays or 2-D gelelectrophoresis combined with mass spectrometry will make it possible to have a faster look from gene to the protein and to find new target genes of compounds as well as new molecular mechanisms involved. The knowledge about complex molecular signalling pathways will give a real impact to new diagnostics in food analytics. As an example reporter gene assays as screening methods in the diagnostic of food contaminants will be discussed. Additionally, another example, the Novel Food will be discussed because the molecular techniques will improve diagnostics and the risk assessment of novel foods.     

A qualitative approach to measure the effectiveness of active avian influenza virus surveillance with respect to its cost: a case study from Switzerland

The aim of the project was to apply cost-effectiveness analysis to the economic appraisal of avian influenza virus (AIV) surveillance, using the implemented surveillance programme in Switzerland as a case study. First a qualitative risk assessment approach was used to assess the expected impact of surveillance on the transmission and spread of AIV. The effectiveness of surveillance was expressed as the difference in defined probabilities between a scenario with surveillance and a scenario without surveillance. The following probabilities were modelled (i) transmission of highly pathogenic AIV (HPAIV) from wild birds to poultry, (ii) mutation from low pathogenic AIV (LPAIV) into HPAIV in poultry, and (iii) transmission of HPAIV to other poultry holdings given a primary outbreak. The cost-effectiveness ratio was defined conventionally as the difference in surveillance costs (ΔC) divided by the change in probability (ΔP), the technical objective, on the presumption that surveillance diminishes the respective probabilities. However, results indicated that surveillance in both wild birds and poultry was not expected to change the probabilities of primary and secondary AIV outbreaks in Switzerland. The overall surveillance costs incurred were estimated at 31,000 €/year, which, to be a rational investment of resources, must still reflect the value policy makers attribute to other benefits from having surveillance (e.g. peace of mind). The advantage of the approach adopted is that it is practical, transparent, and thus able to clarify for policy makers the key variables to be taken into account when evaluating the economic efficiency of resources invested in surveillance, prevention and intervention to exclude AIV.     

Emerging zoonoses: the challenge for public health and biodefense

The concept of new and emerging diseases has captured the public interest and has revitalized the public health infectious disease research community. This interest has also resulted in competition for funding and turf wars between animal health and public health scientists and public officials and, in some cases, has delayed and hindered progress toward effective prevention, control and biodefense. There is a dynamic list of outbreaks causing substantial morbidity and mortality in humans and often in the reservoir animal species. Some agents have the potential to grow into major epidemics. There are many determinants that influence the emergence of diseases of concern that require the use of current understanding of the nature of agent persistence and spread. Additional factors that are global must be added to plans for prevention and control. To this complex mix has been added the potential for accidental or malicious release of agents. The nature of emerging infectious agents and their impact is largely unpredictable. Models that strive to predict the dynamics of agents may be useful but can also blind us to increasing disease risks if it does not match a specific model. Field investigations of early events will be critical and should drive prevention and control actions. Many disease agents have developed strategies to overcome extremes of reservoir qualities like population size and density. Every infectious agent spreads easier when its hosts are closer together. Zoonoses must be dealt with at the interface of human and animal health by all available information. Lessons learned from the emergence of and response to agents like West Nile virus, H5N1 avian influenza, SARS and bovine spongiform encephalopathy, the cause of new-variant Creutzfeldt-Jakob disease in humans, must be used to create better plans for response and meet the challenge for public health and biodefense.     

Quantitative Risk Assessment of Human Trichinellosis Caused by Consumption of Pork Meat Sausages in Argentina

In Argentina, there are three known species of genus Trichinella; however, Trichinella spiralis is most commonly associated with domestic pigs and it is recognized as the main cause of human trichinellosis by the consumption of products made with raw or insufficiently cooked pork meat. In some areas of Argentina, this disease is endemic and it is thus necessary to develop a more effective programme of prevention and control. Here, we developed a quantitative risk assessment of human trichinellosis following pork meat sausage consumption, which may be used to identify the stages with greater impact on the probability of acquiring the disease. The quantitative model was designed to describe the conditions in which the meat is produced, processed, transported, stored, sold and consumed in Argentina. The model predicted a risk of human trichinellosis of 4.88 × 10^?6 and an estimated annual number of trichinellosis cases of 109. The risk of human trichinellosis was sensitive to the number of Trichinella larvae that effectively survived the storage period (r = 0.89), the average probability of infection (P_Pinf) (r = 0.44) and the storage time (Storage) (r = 0.08). This model allowed assessing the impact of different factors influencing the risk of acquiring trichinellosis. The model may thus help to select possible strategies to reduce the risk in the chain of by‐products of pork production.     

白僵菌的分类研究进展

白僵菌(Beauveria)是一类寄主范围广、致病性与适应性很强的昆虫病原真菌,已广泛应用于农林害虫的生物防治,但是有些白僵菌种对家蚕等经济昆虫也存在严重的危害。对国内外近一个多世纪以来有关白僵菌属种的分类研究历史、分类研究方法以及6个白僵菌属种的形态特征予以概述,并简要介绍生物防治环境中避免白僵菌交叉感染家蚕的监测鉴定方法,以期为开展相关白僵菌的分类鉴定和对白僵菌杀虫剂使用的安全性评价及降低给养蚕生产造成危害的风险性提供参考。     

白色念珠菌分子生物学分型方法研究进展

白色念珠菌是一种致病性酵母真菌,可引起人畜口腔、上呼吸道、阴道黏膜及全身性感染。随着抗真菌药物的长期大量使用,真菌的耐药性越来越严重。临床调查结果表明,白色念珠菌感染在真菌感染病例中跃居第2位。正确鉴定与分类有利于对白色念珠菌感染进行及时诊断、预防和治疗。文章主要对白色念珠菌的分子生物学分型方法进行综述。     

Bighorn sheep pneumonia: Sorting out the cause of a polymicrobial disease

Pneumonia of bighorn sheep (Ovis canadensis) is a dramatic disease of high morbidity and mortality first described more than 80 years ago. The etiology of the disease has been debated since its initial discovery, and at various times lungworms, Mannheimia haemolytica and other Pasteurellaceae, and Mycoplasma ovipneumoniae have been proposed as primary causal agents. A multi-factorial “respiratory disease complex” has also been proposed as confirmation of causation has eluded investigators. In this paper we review the evidence for each of the candidate primary agents with regard to causal criteria including strength of association, temporality, plausibility, experimental evidence, and analogy. While we find some degree of biological plausibility for all agents and strong experimental evidence for M. haemolytica, we demonstrate that of the alternatives considered, M. ovipneumoniae is the best supported by all criteria and is therefore the most parsimonious explanation for the disease. The strong but somewhat controversial experimental evidence implicating disease transmission from domestic sheep is consistent with this finding. Based on epidemiologic and microbiologic data, we propose that healthy bighorn sheep populations are naïve to M. ovipneumoniae, and that its introduction to susceptible bighorn sheep populations results in epizootic polymicrobial bacterial pneumonia often followed by chronic infection in recovered adults. If this hypothesized model is correct, efforts to control this disease by development or application of vectored vaccines to Pasteurellaceae are unlikely to provide significant benefits, whereas efforts to ensure segregation of healthy bighorn sheep populations from M. ovipneumoniae-infected reservoir hosts are crucial to prevention of new disease epizootics. It may also be possible to develop M. ovipneumoniae vaccines or other management strategies that could reduce the impact of this devastating disease in bighorn sheep.     

Risk assessments of lumpy skin diseases in Borena bull market chain and its implication for livelihoods and international trade

Risks of introduction of lumpy skin disease (LSD) through traded Borena bulls to market chain and its consequences were assessed. The assessment used the framework that has been recommended by the World Animal Health Organization (OIE) for risk analysis. Likelihoods for release and exposure were estimated by a qualitative scale ranging from negligible to very high, whereas the consequences which resulted from disease occurrences were assessed quantitatively. The likelihood of the introduction of LSD to the market chain through traded Borena bulls is found to be high (medium uncertainty), whereas the probability of exposure is very high (medium uncertainty). From the total of 11,189 bulls observed during outbreak investigation of LSD in six sites of feedlot operation in and around Adama, 681(6.1 %) and 204 (1.8 %) bulls were found to be affected and dead with LSD, respectively. The total economic loss due to LSD was estimated to be 667,785.6 USD. The risk estimates for LSD are greater than negligible; therefore, disease prevention and control strategy along the chain should be carefully considered by the Ethiopian veterinary services.     

Drug dose and drug choice: Optimizing medical therapy for veterinary cancer

Although novel agents hold great promise for the treatment of animal neoplasia, there may be room for significant improvement in the use of currently available agents. These improvements include altered dosing schemes, novel combinations, and patient‐specific dosing or selection of agents. Previous studies have identified surrogates for “individualized dose intensity,”, for example, patient size, development of adverse effects, and pharmacokinetic parameters, as potential indicators of treatment efficacy in canine lymphoma, and strategies for patient‐specific dose escalation are discussed. Strategies for treatment selection in individual patients include conventional histopathology, protein‐based target assessment (eg, flow cytometry, immunohistochemistry, and mass spectrometry), and gene‐based target assessment (gene expression profiling and targeted or global sequencing strategies). Currently available data in animal cancer evaluating these strategies are reviewed, as well as ongoing studies and suggestions for future directions.     

解淀粉芽孢杆菌HZ-6-3的筛选鉴定及其防治番茄灰霉病效果的评价

采用平板对峙法,从银杏组织分离的内生细菌菌株中筛选对灰葡萄孢菌抑菌活性较好的菌株,其中菌株HZ-6-3的抑制作用最强,抑制率为79.06%。通过菌落形态观察、生理生化特征、16S rRNA基因序列和gyrA基因分析将菌株HZ-6-3鉴定为解淀粉芽孢杆菌。抑菌谱测定结果显示,该菌株对其他8种植物病原真菌均具有不同程度的拮抗作用。该菌株可产生蛋白酶、果胶酶、β-1,3-葡聚糖酶和淀粉酶;能够显著抑制病原菌的菌丝生长,使菌丝生长扭曲,细胞膨大、形成串状泡囊结构等畸变。利用盆栽试验测定了该菌株对番茄灰霉病的防控效果,结果显示1×10⁸ CFU·mL^-1的预防效果和治疗效果最高,可达81.12%和70.45%。上述结果显示菌株HZ-6-3具有作为生物制剂的潜能。     

Import risk assessment incorporating a dose–response model: Introduction of highly pathogenic porcine reproductive and respiratory syndrome into Australia via illegally imported raw pork

Highly pathogenic porcine reproductive and respiratory syndrome (PRRS) has spread through parts of south-east Asia, posing a risk to Australia. The objective of this study was to assess the probability of infection of a feral or domestic pig in Australia with highly pathogenic PRRS following ingestion of illegally imported raw pork. A conservative scenario was considered in which 500 g of raw pork was imported from the Philippines into Australia without being detected by border security, then discarded from a household and potentially accessed by a pig. Monte Carlo simulation of a two-dimensional, stochastic model was used to estimate the probability of entry and exposure, and the probability of infection was assessed by incorporating a virus-decay and mechanistic dose–response model. Results indicated that the probability of infection of a feral pig after ingestion of raw meat was higher than the probability of infection of a domestic pig. Sensitivity analysis was used to assess the influence of input parameters on model output probability estimates, and extension of the virus-decay and dose–response model was used to explore the impact of different temperatures and time from slaughter to ingestion of the meat, different weights of meat, and the level of viraemia at slaughter on the infectivity of meat. Parameters with the highest influence on the model output were the level of viraemia of a pig prior to slaughter and the probability of access by a feral pig to food-waste discarded on property surrounding a household. Extension of the decay and dose–response model showed that small pieces of meat (10 g) from a highly pathogenic PRRS viraemic pig could contain enough virus to have a high probability of infection of a pig, and that routes to Australia by sea or air from all highly pathogenic PRRS virus endemic countries were of interest dependent on the temperature of the raw meat during transport. This study highlighted the importance of mitigation strategies such as disposal of food-waste from international traffic as quarantine waste, and the need for further research into the probability of access to food-waste on properties by feral pigs.     

Risk analysis of Bovine Spongiform Encephalopathy in Korea

The occurrence of Bovine Spongiform Encephalopathy (BSE, so called mad cow diseases) that was first identified in England in 1986 was considered as being limited to only European countries, including England. However, the outbreak in Asia as well as North America since 2001 has amplified the fear that there isn't any nation in the world that is a safe area. In order to assess the risk of BSE outbreak in each country, the Office International des Epizooties (OIE) and EU have respectively established criteria, where OIE has set 5 levels and EU has set 4 levels. The Scientific Steering Committee (SSC) of the European Commission conducted a Geographical BSE Risk(GBR) assessment for 64 nations, such as the United States, etc., as of April 29, 2003. However, as of July 1, 2005, the duty of GBR assessment is expected to be transferred to a newly established body called EFSA (European Food Safety Authority, located in Parma, Italy). As Korea has not undergone a GBR assessment up to now, this study analyzed the risk of BSE outbreak in Korea by reviewing BSE prevention measures, etc., that have been put in place. This study shall be a barometer for estimating the GBR assessment level of Korea.