Early qualitative risk assessment of the emerging zoonotic potential of animal diseases

Pairwise summation as a method for the additive combination of probabilities in qualitative risk assessments

Qualitative frameworks are widely employed to tackle urgent animal or public health issues when data are scarce and/or urgent decisions need to be made. In qualitative models, the degree of belief regarding the probabilities of the events occurring along the risk pathway(s) and the outcomes is described in nonnumerical terms, typically using words such as Low, Medium, or High. The main methodological challenge, intrinsic in qualitative models, relates to performing mathematical operations and adherence to the rule of probabilities when probabilities are nonnumerical. Although methods to obtain the qualitative probability from the conditional realization of n events are well-established and consistent with the multiplication rule of probabilities, there is a lack of accepted methods for addressing situations where the probability of an event occurring can increase, and the rule of probability P(AUB) = P(A) + P(B) - P(A∩B) should apply. In this work, we propose a method based on the pairwise summation to fill this methodological gap. Our method was tested on two qualitative models and compared by means of scenario analysis to other approaches found in literature. The qualitative nature of the models prevented formal validation; however, when using the pairwise summation, results consistently appeared more coherent with probability rules. Even if the final qualitative estimate can only represent an approximation of the actual probability of the event occurring, qualitative models have proven to be effective in providing scientific-based evidence to support decision-making. The method proposed in this study contributes to reducing the subjectivity that characterizes qualitative models, improving transparency and reproducibility.

Risk Assessment and Response Strategy for Pig Epidemics in China

Strengthening the analysis and risk assessment of the pig epidemic will help to better prevent and mitigate epidemic risks and promote the high-quality development of the pig industry. Based on a systematic understanding of live pig epidemics, a risk assessment index system was constructed, and the spatial and temporal variation characteristics of pig epidemics in China were explored by the entropy method. In recent years, the overall trend in pig epidemics over time first increased and then decreased; in space, the acceleration of the spread of epidemics across the country weakened. China still faces challenges, including many types and a wide range of diseases, large total livestock breeding and weak epidemic prevention and control capacity, and a large risk of introduced foreign animal epidemics. The spatial and temporal variations in the pig epidemic risk were obvious; one high-risk area, two medium-high-risk areas and 10 medium-risk areas have been found in recent years, during which time, the epidemic risk was highest in Beijing, Hainan, Liaoning, Tibet and Zhejiang. However, there were significant differences in the regional distribution of the risk level of pig epidemics in different years. To further build a secure "defense system" for the high-quality development of the pig industry, it is recommended to improve the monitoring and early warning system of pig epidemic risk, perfect the pig epidemic prevention and control system, and strengthen the regional collaboration mechanism of epidemic prevention and control.

The right strategy for you: Using the preferences of beef farmers to guide biosecurity recommendations for on-farm management of endemic disease

Effective on-farm biosecurity measures are crucial to the post-border protection of emerging agricultural diseases and are the foundation of endemic disease control. Implementation of on-farm biosecurity measures are contingent on the priorities of individual producers, which can often be neglected for other aspects of the farming enterprise. The on-farm approach to prevention of endemic diseases, like bovine viral diarrhoea virus (BVDV), is inconsistent between farms and it is not realistic to assume that farmers take an entirely normative approach to on-farm decision making. Multi-criteria decision analysis (MCDA) has been used for disease prioritisation and national disease control in human and animal health; however, it is yet to be used as a decision tool for disease control at the farm level. This study used MCDA to determine the most appropriate biosecurity combinations for management of BVDV, based on the preferences of Australian beef producers. Beef producer preferences were obtained from an online survey using indirect collection methods. Point of truth calibration was used to aggregate producer preferences and the performance scores of 23 biosecurity combinations for control of BVDV based on four main criteria: the probability of BVDV introduction, the on-farm impact of BVDV, the off-farm impact of BVDV and the annual input cost of the practice. The MCDA found that biosecurity combinations that included "double-fencing farm boundaries" used in conjunction with "vaccination against BVDV" were most appropriate for management of BVDV in an initially naïve, self-replacing seasonal single-calving beef herd over a 15-year period. Beef producers prioritised practices that preserved the on-farm health of their cattle more than any other criteria, a finding that was persistent regardless of demographic or farming type. Consequently, combinations with "vaccination against BVDV" were consistently ranked higher than those that included "strategic exposure of a persistently infected cow," which is sometimes used by Australian beef producers instead of vaccination. Findings of this study indicate that the benefits of "double-fencing farm boundaries" and "vaccination against BVDV" outweigh the relatively high cost associated with these practices based on the priorities of the Australian beef producer and may be used to demonstrate the benefits of on-farm biosecurity during discussions between livestock veterinarians and beef farmers.

The science of the host-virus network

Better methods to predict and prevent the emergence of zoonotic viruses could support future efforts to reduce the risk of epidemics. We propose a network science framework for understanding and predicting human and animal susceptibility to viral infections. Related approaches have so far helped to identify basic biological rules that govern cross-species transmission and structure the global virome. We highlight ways to make modelling both accurate and actionable, and discuss the barriers that prevent researchers from translating viral ecology into public health policies that could prevent future pandemics.

SDAV, the Rat Coronavirus-How Much Do We Know about It in the Light of Potential Zoonoses

Sialodacryoadenitis virus (SDAV) is known to be an etiological agent, causing infections in laboratory rats. Until now, its role has only been considered in studies on respiratory and salivary gland infections. The scant literature data, consisting mainly of papers from the last century, do not sufficiently address the topic of SDAV infections. The ongoing pandemic has demonstrated, once again, the role of the Coronaviridae family as extremely dangerous etiological agents of human zoonoses. The ability of coronaviruses to cross the species barrier and change to hosts commonly found in close proximity to humans highlights the need to characterize SDAV infections. The main host of the infection is the rat, as mentioned above. Rats inhabit large urban agglomerations, carrying a vast epidemic threat. Of the 2277 existing rodent species, 217 are reservoirs for 66 zoonotic diseases caused by viruses, bacteria, fungi, and protozoa. This review provides insight into the current state of knowledge of SDAV characteristics and its likely zoonotic potential.

First detection of bovine noroviruses and detection of bovine coronavirus in Australian dairy cattle

Background and objective

Noroviruses have been recognised as a significant cause of neonatal enteritis in calves in many countries, but there has been no investigation of their occurrence in Australian cattle. This study aimed to establish whether bovine noroviruses could be detected in faecal samples from Australian dairy cattle. It also sought to determine whether bovine coronaviruses, also associated with neonatal enteritis in calves, could be detected in the same faecal samples.

Methods

A selection of faecal samples that were negative for rotaviruses from dairy farms located in three geographically distinct regions of Victoria were pooled and tested by reverse transcription‐PCR for the presence of noroviruses (genogroup III), neboviruses and bovine coronaviruses.

Results and conclusion

Genetically distinct genogroup III noroviruses were detected in two sample pools from different geographic regions and bovine coronavirus was detected in a third pool of samples. This is the first report of bovine norovirus infection in Australian cattle and suggests that future work is required to determine the significance of these agents as a cause of bovine enteric disease in Australia.

World Health Organization Methodology to Prioritize Emerging Infectious Diseases in Need of Research and Development

The World Health Organization R&D Blueprint aims to accelerate the availability of medical technologies during epidemics by focusing on a list of prioritized emerging diseases for which medical countermeasures are insufficient or nonexistent. The prioritization process has 3 components: a Delphi process to narrow down a list of potential priority diseases, a multicriteria decision analysis to rank the short list of diseases, and a final Delphi round to arrive at a final list of 10 diseases. A group of international experts applied this process in January 2017, resulting in a list of 10 priority diseases. The robustness of the list was tested by performing a sensitivity analysis. The new process corrected major shortcomings in the pre-R&D Blueprint approach to disease prioritization and increased confidence in the results.

Zika Virus in Ontario: Evaluating a Rapid Risk Assessment Tool for Emerging Infectious Disease Threats

To determine the Ontario-specific risk of local and travel-related Zika virus transmission in the context of a public health emergency of international concern, Public Health Ontario (PHO) completed a rapid risk assessment (RRA) on January 29, 2016, using a newly developed RRA guidance tool. The RRA concluded that risk of local mosquito-borne transmission was low, with a high risk of imported cases through travel. The RRA was updated 3 times based on predetermined triggers. An independent evaluation assessed both the application of the RRA guidance tool (process evaluation) and the usefulness of the RRA (outcome evaluation). We conducted face-to-face, semi-structured interviews with 7 individuals who participated in the creation or review of the Zika virus RRA and 4 end-users at PHO and the Ministry of Health and Long-Term Care. An inductive thematic analysis of responses was undertaken, whereby themes were directly informed by the data. The process evaluation determined that most steps outlined in the RRA guidance tool were adhered to, including forming a cross-functional writing team, clarifying the scope and describing context, completing the RRA summary report, and updating the RRA based on predefined triggers. The outcome evaluation found that end-users judged the Zika virus RRA as evidence-informed, useful, consistent, and timely. The evaluation established that the locally tailored guidance tool, adapted from national and international approaches to RRAs, facilitated a systematic, evidence-informed, and timely formal RRA process at PHO for the Zika virus RRA, which met the needs of end-users. Based on the evaluation, PHO will modify future RRAs by incorporating some flexibility into the literature review process to support timeliness of the RRA, explicitly describing the limitations of studies used to inform the RRA, and refining risk algorithms to better suit emerging infectious disease threats. It is anticipated that these refinements will improve upon the timely assessment of novel or reemerging infectious diseases.

Laboratory preparedness and response with a focus on arboviruses in Europe

BACKGROUND

The global health burden of arboviruses is continuously rising, which results in increasing pressure on local and (inter)national laboratory infrastructures. Timely and accurate diagnosis of cases is one of the main pillars for public health and clinical responses to an arbovirus emergence.

AIMS AND SOURCES

This narrative review aims to summarize recent advances and to identify needs in laboratory preparedness and response activities, with a focus on viruses transmitted by arthropods in Europe. The review is based on evidence extracted from PubMed searches, Public Health and clinical laboratory experiences from the authors and the authors' opinions substantiated by peer-reviewed scientific literature.

CONTENT

We illustrate the importance of inter-epidemic laboratory preparedness activities to ensure adequate Public Health and clinical responses. We describe the status of arbovirus endemicity and emergence in Europe thereby highlighting the need for preparedness for these viruses. We discuss the components and pitfalls of an adequate laboratory preparedness and response and the broader context of the current landscape of international research, clinical and laboratory preparedness networks. The complexity of arbovirus laboratory preparedness and response is described.

IMPLICATIONS

Outbreak preparedness plans need to look beyond national reference laboratories, to include first-line responding onsite hospital laboratories and plans for strengthening of such local capacity and capability as required depending on the nature of the outbreak. In particular, the diagnosis of arbovirus infections is complicated by the existence of geographic overlap of circulation of numerous arboviruses, the overlap in clinical manifestation between many arboviruses and other aetiologies and the existence of cross-reactivity between related arboviruses in serology testing. Inter-epidemic preparedness activities need strong national and international networks addressing these issues. However, the current mushrooming of European preparedness networks requires governance to bring the European preparedness and response to a next level.

Identification, assessment and management of new and re-emerging animal-related risks: UK perspective

Veterinary surveillance programmes aim to reduce the burden to the public, livestock and wider society posed by animal-related ‘risks’ (referred to as ‘threats’ later in the paper in line with a definition used by the European Food Safety Authority) including the reemergence of diseases believed absent or eradicated. To achieve this, it is important to have a systematic approach to identifying and dealing with such threats rapidly and effectively. This paper describes the transparent, systematic and auditable process used for identifying, assessing, escalating and prioritising new and re-emerging animal-related threats in the UK. This has been achieved through the establishment of a Veterinary Risk Group in late 2009.

Point of truth calibration for disease prioritisation-A case study of prioritisation of exotic diseases for the pig industry in Australia

The objective of this study was to trial point of truth calibration (POTCal) as a novel method for disease prioritisation. To illustrate the application of this method, we used a previously described case-study of prioritisation of exotic diseases for the pig industry in Australia. Disease scenarios were constructed from criteria which described potential impact and pig-producers were asked to score the importance of each scenario. POTCal was used to model participants' estimates of disease importance as a function of the criteria, to derive a predictive model to prioritise a range of exotic diseases. The best validation of producers' estimates was achieved using a model derived from all responses. The highest weighted criteria were attack rate, case fatality rate and market loss, and the highest priority diseases were the vesicular diseases followed by swine fevers and zoonotic encephalitides. Comparison of results with a previous study in which probabilistic inversion was used to prioritise diseases for the same group of producers highlighted differences between disease prioritisation methods. Overall, this study demonstrated that POTCal can be used for disease prioritisation. An advantage of POTCal is that valid models can be developed that reflect decision-makers' heuristics. Specifically, this evaluation of the use of POTCal in animal health illustrates how the judgements of participants can be incorporated into a decision-making process. Further research is needed to investigate the influence of scenarios presented to participants during POTCal evaluations, and the robustness of this approach applied to different disease issues (e.g. exotic versus endemic) and production types (e.g. intensive versus extensive). To our knowledge, this is the first report of the use of POTCal for disease prioritisation.

Best practices in ranking communicable disease threats: a literature review, 2015

The threat of serious, cross-border communicable disease outbreaks in Europe poses a significant challenge to public health and emergency preparedness because the relative likelihood of these threats and the pathogens involved are constantly shifting in response to a range of changing disease drivers. To inform strategic planning by enabling effective resource allocation to manage the consequences of communicable disease outbreaks, it is useful to be able to rank and prioritise pathogens. This paper reports on a literature review which identifies and evaluates the range of methods used for risk ranking. Searches were performed across biomedical and grey literature databases, supplemented by reference harvesting and citation tracking. Studies were selected using transparent inclusion criteria and underwent quality appraisal using a bespoke checklist based on the AGREE II criteria. Seventeen studies were included in the review, covering five methodologies. A narrative analysis of the selected studies suggests that no single methodology was superior. However, many of the methods shared common components, around which a 'best-practice' framework was formulated. This approach is intended to help inform decision makers' choice of an appropriate risk-ranking study design.

Occurrence of Noroviruses and Their Correlation with Microbial Indicators in Raw Milk

This study was conducted to investigate the microbiological quality of raw cow's milk in a collection center in the city of Mashhad, Iran. A total of 19 raw cow's milk samples were collected and simultaneously analyzed for male-specific (F(+)) coliphage and Escherichia coli using culture-based methods and for enteric viruses by reverse transcriptase semi-nested PCR using primer sets specific for human norovirus Group I (HNV-GI), human norovirus Group II (HNV-GII), and enteroviruses (EV). Seven out of 19 (36.8%) raw milk samples tested positive for human noroviruses (HNV). The genotypes detected were HNV-GI and HNV-GII. Three positive samples contained both genotypes, and 2 samples were positive for either of HNV-GI and HNV-GII. No sample tested positive for EV. The correlation between the occurrence of HNV and the microbial indicators was studied. The statistical analysis using first- and second-order regression revealed that there is no correlation between F(+) coliphage and E. coli. Similarly, no correlation was noticed between the occurrence of F(+) coliphages and HNV. However, frequency distribution analysis indicated that 3 out of 4 (75%) of raw milk samples containing F(+) coliphage at a concentration higher than 10(4) pfu/100 ml were also positive for noroviruses. The limited data on the occurrence of noroviruses in raw milk suggest a poor sanitation and hygiene practices at the facility and indicate a possible correlation between the viral indicator at high concentration and human noroviruses; however, this analysis needs further investigation in a larger scale study.

Preparedness for emerging infectious diseases: pathways from anticipation to action

Emerging and re-emerging infectious disease (EID) events can have devastating human, animal and environmental health impacts. The emergence of EIDs has been associated with interconnected economic, social and environmental changes. Understanding these changes is crucial for EID preparedness and subsequent prevention and control of EID events. The aim of this review is to describe tools currently available for identification, prioritization and investigation of EIDs impacting human and animal health, and how these might be integrated into a systematic approach for directing EID preparedness. Environmental scanning, foresight programmes, horizon scanning and surveillance are used to collect and assess information for rapidly responding to EIDs and to anticipate drivers of emergence for mitigating future EID impacts. Prioritization of EIDs - using transparent and repeatable methods - based on disease impacts and the importance of those impacts to decision-makers can then be used for more efficient resource allocation for prevention and control. Risk assessment and simulation modelling methods assess the likelihood of EIDs occurring, define impact and identify mitigation strategies. Each of these tools has a role to play individually; however, we propose integration of these tools into a framework that enhances the development of tactical and strategic plans for emerging risk preparedness.

A análise de risco como ferramenta estratégica para o serviço veterinário oficial brasileiro: dificuldades e desafios

O serviço veterinário oficial é responsável por proteger a saúde pública e animal, assegurando a oferta de produtos de origem animal inócuos aos consumidores. Uma ferramenta que auxilia na busca desses objetivos é a análise de risco, que iniciou a ser utilizada na segunda metade da década de 90 pelos serviços veterinários oficiais dos países. Para a realização de uma análise de risco, qualitativa ou quantitativa, inicialmente deve-se identificar o perigo, a qual na área da saúde animal geralmente é o agente patogênico causador de uma doença. A etapa subsequente é a avaliação do risco, na qual devem ser analisados, com suporte de trabalhos científicos ou especialistas na área, as formas possíveis de introdução, exposição e manutenção do agente patogênico na população susceptível, bem como as consequências, biológicas, econômicas, políticas e sociais trazidas pela enfermidade. A terceira etapa da análise de risco refere-se ao manejo dos riscos, que visa propor medidas que mitiguem o risco verificado até o nível desejado, bem como avaliar o custo/benefício de cada medida. A última fase de uma análise de risco é a comunicação dos riscos. Essa etapa é fundamental para o sucesso do estudo e deve ser iniciada juntamente com a análise de risco em si, sempre deixando aberto um canal permanente de comunicação com todos os atores sociais interessados na análise de risco. A análise de risco tornou-se um importante instrumento utilizado pelos gestores dos serviços veterinários oficiais na tomada de decisões, contribuindo para a escolha de alternativas que confiram, cientificamente, o menor risco sanitário. Este trabalho realizou uma revisão da literatura sobre análise de risco objetivando expor sua definição e processo de elaboração, assim como verificar como ela está sendo utilizada, quais limitações e desafios do uso dessa ferramenta pelo serviço veterinário oficial brasileiro.

Building a picture: Prioritisation of exotic diseases for the pig industry in Australia using multi-criteria decision analysis

Diseases that are exotic to the pig industry in Australia were prioritised using a multi-criteria decision analysis framework that incorporated weights of importance for a range of criteria important to industry stakeholders. Measurements were collected for each disease for nine criteria that described potential disease impacts. A total score was calculated for each disease using a weighted sum value function that aggregated the nine disease criterion measurements and weights of importance for the criteria that were previously elicited from two groups of industry stakeholders. One stakeholder group placed most value on the impacts of disease on livestock, and one group placed more value on the zoonotic impacts of diseases. Prioritisation lists ordered by disease score were produced for both of these groups. Vesicular diseases were found to have the highest priority for the group valuing disease impacts on livestock, followed by acute forms of African and classical swine fever, then highly pathogenic porcine reproductive and respiratory syndrome. The group who valued zoonotic disease impacts prioritised rabies, followed by Japanese encephalitis, Eastern equine encephalitis and Nipah virus, interspersed with vesicular diseases. The multi-criteria framework used in this study systematically prioritised diseases using a multi-attribute theory based technique that provided transparency and repeatability in the process. Flexibility of the framework was demonstrated by aggregating the criterion weights from more than one stakeholder group with the disease measurements for the criteria. This technique allowed industry stakeholders to be active in resource allocation for their industry without the need to be disease experts. We believe it is the first prioritisation of livestock diseases using values provided by industry stakeholders. The prioritisation lists will be used by industry stakeholders to identify diseases for further risk analysis and disease spread modelling to understand biosecurity risks to this industry.

Molecular detection and genotyping of noroviruses

Noroviruses (NoVs) are a major cause of gastroenteritis worldwide in humans and animals and are known as very infectious viral agents. They are spread through feces and vomit via several transmission routes involving person-to-person contact, food, and water. Investigation of these transmission routes requires sensitive methods for detection of NoVs. As NoVs cannot be cultivated to date, detection of these viruses relies on the use of molecular methods such as (real-time) reverse transcriptase polymerase chain reaction (RT-PCR). Regardless of the matrix, detection of NoVs generally requires three subsequent steps: a virus extraction step, RNA purification, and molecular detection of the purified RNA, occasionally followed by molecular genotyping. The current review mainly focused on the molecular detection and genotyping of NoVs. The most conserved region in the genome of human infective NoVs is the ORF1/ORF2 junction and has been used as a preferred target region for molecular detection of NoVs by methods such as (real-time) RT-PCR, NASBA, and LAMP. In case of animal NoVs, broad range molecular assays have most frequently been applied for molecular detection. Regarding genotyping of NoVs, five regions situated in the polymerase and capsid genes have been used for conventional RT-PCR amplification and sequencing. As the expected levels of NoVs on food and in water are very low and inhibition of molecular methods can occur in these matrices, quality control including adequate positive and negative controls is an essential part of NoV detection. Although the development of molecular methods for NoV detection has certainly aided in the understanding of NoV transmission, it has also led to new problems such as the question whether low levels of human NoV detected on fresh produce and shellfish could pose a threat to public health.

Serosurvey of veterinary conference participants for evidence of zoonotic exposure to canine norovirus - study protocol

Background

Noroviruses have emerged as the leading cause of outbreaks and sporadic cases of acute gastroenteritis in humans worldwide. Person-to-person contact and consumption of contaminated food are considered the most important ways of transmission of noroviruses however zoonotic transmission has been suggested. Recently, noroviruses have been found in dogs which, unlike bovine and swine noroviruses, may present a higher risk of zoonotic transfer, given to the often close contacts between humans and pet dogs in many societies across the world. The present paper describes a seroepidemiologic study aiming to provide information on the exposure level of humans to canine norovirus.

Methods/Design

A case–control study was designed to address the potential exposure to canine norovirus based on the presence of antibodies against canine norovirus. Sera from veterinarians (a population repeatedly in close contact with dogs) will be collected in an annual Veterinary Sciences Congress in Portugal. In addition, sera from general population will be obtained and used as controls for comparative purposes. All sera will be tested for the presence of canine norovirus antibodies using a virus-like particle-based enzyme immune assay. Risk factors for canine norovirus antibodies presence in veterinarians will be investigated through the delivery of an anonymized questionnaire to the participants.

Discussion

The present study aims to identify seropositive individuals to canine norovirus and to assess risk profiles among veterinary professionals with occupational exposure to dogs. To our knowledge this is the first study providing information on the potential zoonotic risk of canine norovirus, thus allowing the development of preventive measures and ascertaining potential risks for Public Health resulting from contact to dogs.

Development of an algorithm for assessing the risk to food safety posed by a new animal disease

An algorithm was developed as a tool to rapidly assess the potential for a new or emerging disease of livestock to adversely affect humans via consumption or handling of meat product, so that the risks and uncertainties can be understood and appropriate risk management and communication implemented. An algorithm describing the sequence of events from occurrence of the disease in livestock, release of the causative agent from an infected animal, contamination of fresh meat and then possible adverse effects in humans following meat handling and consumption was created. A list of questions complements the algorithm to help the assessors address the issues of concern at each step of the decision pathway. The algorithm was refined and validated through consultation with a panel of experts and a review group of animal health and food safety policy advisors via five case studies of potential emerging diseases of cattle. Tasks for model validation included describing the path taken in the algorithm and stating an outcome. Twenty-nine per cent of the 62 experts commented on the model, and one-third of those responding also completed the tasks required for model validation. The feedback from the panel of experts and the review group was used to further develop the tool and remove redundancies and ambiguities. There was agreement in the pathways and assessments for diseases in which the causative agent was well understood (for example, bovine pneumonia due to Mycoplasma bovis). The stated pathways and assessments of other diseases (for example, bovine Johne's disease) were not as consistent. The framework helps to promote objectivity by requiring questions to be answered sequentially and providing the opportunity to record consensus or differences of opinion. Areas for discussion and future investigation are highlighted by the points of diversion on the pathway taken by different assessors.

Infection of calves with bovine norovirus GIII.1 strain Jena virus: an experimental model to study the pathogenesis of norovirus infection

The experimental infection of newborn calves with bovine norovirus was used as a homologous large animal model to study the pathogenesis of norovirus infection and to determine target cells for viral replication. Six newborn calves were inoculated orally with Jena virus (JV), a bovine norovirus GIII.1 strain, and six calves served as mock-inoculated controls. Following infection, calves were euthanized before the onset of diarrhea (12 h postinoculation [hpi]), shortly after the onset of diarrhea (18 to 21 hpi), and postconvalescence (4 days pi [dpi]). Calves inoculated with JV developed severe watery diarrhea at 14 to 16 hpi, and this symptom lasted for 53.5 to 67.0 h. Intestinal lesions were characterized by severe villus atrophy together with loss and attenuation of villus epithelium. Viral capsid antigen (JV antigen) was detected by immunohistochemistry in the cytoplasm of epithelial cells on villi. In addition, granular material positive for JV antigen was detected in the lamina propria of villi. Lesions first appeared at 12 hpi and were most extensive at 18 to 19 hpi, extending from midjejunum to ileum. The intestinal mucosa had completely recovered at 4 dpi. There was no indication of systemic infection as described for norovirus infection in mice. JV was found in intestinal contents by reverse transcription-PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) as early as 12 hpi. Fecal shedding of the virus started at 13 hpi and stopped at 23 hpi or at necropsy (4 dpi), respectively. Throughout the trial, none of the control calves tested positive for JV by ELISA or RT-PCR.

Emerging swine zoonoses

The majority of emerging infectious diseases are zoonotic in origin. Swine represent a potential reservoir for many novel pathogens and may transmit these to humans via direct contact with live animals (such as swine farmers and large animal veterinarians), or to the general human population via contaminated meat. We review recent emerging microbes associated with swine and discuss public health implications.

Prioritizing emerging zoonoses in the Netherlands

Background

To support the development of early warning and surveillance systems of emerging zoonoses, we present a general method to prioritize pathogens using a quantitative, stochastic multi-criteria model, parameterized for the Netherlands.

Methodology/Principal Findings

A risk score was based on seven criteria, reflecting assessments of the epidemiology and impact of these pathogens on society. Criteria were weighed, based on the preferences of a panel of judges with a background in infectious disease control.

Conclusions/Significance

Pathogens with the highest risk for the Netherlands included pathogens in the livestock reservoir with a high actual human disease burden (e.g. Campylobacter spp., Toxoplasma gondii, Coxiella burnetii) or a low current but higher historic burden (e.g. Mycobacterium bovis), rare zoonotic pathogens in domestic animals with severe disease manifestations in humans (e.g. BSE prion, Capnocytophaga canimorsus) as well as arthropod-borne and wildlife associated pathogens which may pose a severe risk in future (e.g. Japanese encephalitis virus and West-Nile virus). These agents are key targets for development of early warning and surveillance.

Transmission routes and risk factors for autochthonous hepatitis E virus infection in Europe: a systematic review

Increasing numbers of non-travel-associated hepatitis E virus (HEV) infections have been reported in Europe in recent years. Our objective was to review the evidence on risk factors and transmission routes of autochthonous HEV infection and hepatitis E in Europe in order to develop recommendations for future research, prevention and control. A systematic literature review was performed to identify all primary reports and studies published during 1998-2008 on hepatitis E in humans and animals in Europe by searching Pubmed, reference lists of major articles and international conference proceedings. Each of the 106 included studies was categorized into one of three evidence levels (EL) based on study design and diagnostic methodology. The evidence was generally weak (73 were assigned to EL1, two to both EL1 and EL2, and 30 to EL2), further compounded by the use of poorly validated serological assays in some studies. Only one case-control study was assigned to EL3. Persons with autochthonous hepatitis E infection were on average older than the general population and predominantly male. There was no evidence for one main transmission route of HEV infection or risk factor for hepatitis E. However, zoonotic transmission seemed likely and person-to-person transmission too inefficient to cause clinical disease. Multiple routes of transmission probably exist and should be further investigated through analytical studies and reliable diagnostic kits. Based on current evidence that points to zoonotic transmission from pigs, thorough cooking of all porcine products, prevention of cross-contamination in the kitchen and improved education for occupationally exposed people (e.g. pig farmers, veterinarians and sewage workers) may help prevent HEV infection. Although evidence for parenteral transmission is limited, it is recommended that a risk assessment is undertaken.

Assessing the risk from emerging infections

Emerging infections pose a constant threat to society and can require a substantial response, thus systems to assess the threat level and inform prioritization of resources are essential. A systematic approach to assessing the risk from emerging infections to public health in the UK has been developed. This qualitative assessment of risk is performed using algorithms to consider the probability of an infection entering the UK population, and its potential impact, and to identify knowledge gaps. The risk assessments are carried out by a multidisciplinary, cross-governmental group of experts working in human and animal health. This approach has been piloted on a range of infectious threats identified by horizon scanning activities. A formal risk assessment of this nature should be considered for any new or emerging infection in humans or animals, unless there is good evidence that the infection is neither a recognized human disease nor a potential zoonosis.

Duties and functions of veterinary public health for the management of food safety: present needs and evaluation of efficiency

Functions of veterinarians in the context of food safety assurance have changed very much in the last ten years as a consequence of new legislation. The aim of this review is to evaluate the management tools in veterinary public health that shall be used in response to the actual need and consider some possible key performance indicators. This review involved an examination of the legislation, guidelines and literature, which was then discussed to analyse the actual need, the strategies and the procedures with which the public veterinary service shall comply. The management of information gathered at different stages of the food chain, from both food production operators and veterinary inspectors operating in primary production, food processing and feed production should be exchanged and integrated in a database, not only to produce annual reports and plan national sampling plans, but also to verify and validate the effectiveness of procedures and strategies implemented by food safety operators to control risks. Further, the surveillance data from environmental agencies and human epidemiological units should be used for assessing risks and addressing management options.

Macaque models of human infectious disease

Macaques have served as models for more than 70 human infectious diseases of diverse etiologies, including a multitude of agents—bacteria, viruses, fungi, parasites, prions. The remarkable diversity of human infectious diseases that have been modeled in the macaque includes global, childhood, and tropical diseases as well as newly emergent, sexually transmitted, oncogenic, degenerative neurologic, potential bioterrorism, and miscellaneous other diseases. Historically, macaques played a major role in establishing the etiology of yellow fever, polio, and prion diseases. With rare exceptions (Chagas disease, bartonellosis), all of the infectious diseases in this review are of Old World origin. Perhaps most surprising is the large number of tropical (16), newly emergent (7), and bioterrorism diseases (9) that have been modeled in macaques. Many of these human diseases (e.g., AIDS, hepatitis E, bartonellosis) are a consequence of zoonotic infection. However, infectious agents of certain diseases, including measles and tuberculosis, can sometimes go both ways, and thus several human pathogens are threats to nonhuman primates including macaques. Through experimental studies in macaques, researchers have gained insight into pathogenic mechanisms and novel treatment and vaccine approaches for many human infectious diseases, most notably acquired immunodeficiency syndrome (AIDS), which is caused by infection with human immunodeficiency virus (HIV). Other infectious agents for which macaques have been a uniquely valuable resource for biomedical research, and particularly vaccinology, include influenza virus, paramyxoviruses, flaviviruses, arenaviruses, hepatitis E virus, papillomavirus, smallpox virus, Mycobacteria, Bacillus anthracis, Helicobacter pylori, Yersinia pestis, and Plasmodium species. This review summarizes the extensive past and present research on macaque models of human infectious disease.

Serological response to hepatitis E virus genotype 3 infection: IgG quantitation, avidity, and IgM response

Sequential sera were collected from 18 acute cases of UK-acquired hepatitis E. The virus strains in all cases were of genotype 3. The IgM and IgG response to acute infection were documented over time using EIA kits based on a peptide antigen, pE2, which is derived from a genotype 1 strain of hepatitis E virus (HEV). Ninety-five percentage of acute sera were IgM positive; after 6 months or more only 12% remained positive. The kit was adapted to quantify the IgG response (in WHO U/ml) and to determine antibody avidity. Following acute infection, anti-HEV IgG concentrations rose between 6.9- and 90-fold. IgG avidity was low (<25%) in most acute sera. After 6 months IgG avidity was greater than 50% in all cases. One patient with a poor IgM response and high avidity antibody in acute sera may have had a second HEV infection. Taken together, these results confirm that the pE2-based EIA kits are suitable for diagnosing acute HEV genotype 3 infection. With simple modifications the IgG kit can measure anti-HEV concentration and avidity, which can be used to confirm acute infection.