地理信息系统与动物流行病学

地理信息系统作为一种能对空间数据进行处理的计算机程序系统已被广泛应用在众多与空间信息操作有关的领域。在动物流行病学研究中 ,研究人员通过建立一些用于分析疫病分布时空模式的方法和模型 ,应用地理信息系统进行了许多疾病的空间分布模式、流行趋势、环境危险因素分布、辅助控制计划制定及控制效果评估等方面的研究 ,取得了很好的效果。地理信息系统已经成为当前进行流行病学研究的重要工具     

Epidemiological simulation modeling and spatial analysis for foot-and-mouth disease control strategies: a comprehensive review

Foot-and-mouth disease (FMD) is one of the most serious transboundary, contagious viral diseases of cloven-hoofed livestock, because it can spread rapidly with high morbidity rates when introduced into disease-free herds or areas. Epidemiological simulation modeling can be developed to study the hypothetical spread of FMD and to evaluate potential disease control strategies that can be implemented to decrease the impact of an outbreak or to eradicate the virus from an area. Spatial analysis, a study of the distributions of events in space, can be applied to an area to investigate the spread of animal disease. Hypothetical FMD outbreaks can be spatially analyzed to evaluate the effect of the event under different control strategies. The main objective of this paper is to review FMD-related articles on FMD epidemiology, epidemiological simulation modeling and spatial analysis with the focus on disease control. This review will contribute to the development of models used to simulate FMD outbreaks under various control strategies, and to the application of spatial analysis to assess the outcome of FMD spread and its control.     

Changing dietary habits in a changing world: emerging drivers for the transmission of foodborne parasitic zoonoses

Changing eating habits, population growth and movements, global trade of foodstuff, changes in food production systems, climate change, increased awareness and better diagnostic tools are some of the main drivers affecting the emergence or re-emergence of many foodborne parasitic diseases in recent years. In particular, the increasing demand for exotic and raw food is one of the reasons why reports of foodborne infections, and especially waterborne parasitosis, have increased in the last years. Moreover increasing global demand for protein of animal origin has led to certain farming practices (e.g. aquaculture) increasing in emerging or developing countries, where health monitoring may not be sufficiently implemented. Therefore, high quality epidemiological data are needed which together with biological, economic, social and cultural variables should be taken into account when setting control programs for these increasingly popular production systems in emerging economies. This review focuses on the dietary, social, economic and environmental changes that may cause an increase in human exposure to foodborne parasites. Some examples illustrating these new epidemiological dynamics of transmission foodborne parasitic disease are presented.     

A review of foot-and-mouth disease with special consideration for the clinical and epidemiological factors relevant to predictive modelling of the disease

Modelling the epidemiology of foot-and-mouth disease (FMD) has been undertaken since the early 1970s. We review here clinical factors and modelling procedures that have been used in the past, differentiating between those that have proved to be more relevant in controlling FMD epidemics, and those that have showed less significance. During the 2001 UK FMD epidemic, many previously developed FMD models were available for consideration and use. Accurate epidemiological models can become useful tools for determining relevant control policies for different scenarios and, conversely, inaccurate models may become an abuse for disease control. Inaccuracy presents two opposing difficulties. Firstly, too much control (in terms of animal slaughter for 2001) would negatively impact the farming community for many subsequent years, whilst too little control would permit an epidemic to persist. Accuracy however, presents the optimal permutation of control measures that could be implemented for a given set of conditions, and is a prerequisite to boosting public confidence in the use of epidemiological models for future epidemics.     

An integrated web system to support veterinary activities in Italy for the management of information in epidemic emergencies

The management of public health emergencies is improved by quick, exhaustive and standardized flow of data on disease outbreaks, by using specific tools for data collection, registration and analysis. In this context, the National Information System for the Notification of Outbreaks of Animal Diseases (SIMAN) has been developed in Italy to collect and share data on the notifications of outbreaks of animal diseases. SIMAN is connected through web services to the national database of animals and holdings (BDN) and has been integrated with tools for the management of epidemic emergencies. The website has been updated with a section dedicated to the contingency planning in case of epidemic emergency. EpiTrace is one such useful tool also integrated in the BDN and based on the Social Network Analysis (SNA) and on network epidemiological models. This tool gives the possibility of assessing the risk associated to holdings and animals on the basis of their trade, in order to support the veterinary services in tracing back and forward the animals in case of outbreaks of infectious diseases.     

Models to capture the potential for disease transmission in domestic sheep flocks

Successful control of livestock diseases requires an understanding of how they spread amongst animals and between premises. Mathematical models can offer important insight into the dynamics of disease, especially when built upon experimental and/or field data. Here the dynamics of a range of epidemiological models are explored in order to determine which models perform best in capturing real-world heterogeneities at sufficient resolution. Individual based network models are considered together with one- and two-class compartmental models, for which the final epidemic size is calculated as a function of the probability of disease transmission occurring during a given physical contact between two individuals. For numerical results the special cases of a viral disease with a fast recovery rate (foot-and-mouth disease) and a bacterial disease with a slow recovery rate (brucellosis) amongst sheep are considered. Quantitative results from observational studies of physical contact amongst domestic sheep are applied and results from the differently structured flocks (ewes with newborn lambs, ewes with nearly weaned lambs and ewes only) compared. These indicate that the breeding cycle leads to significant changes in the expected basic reproduction ratio of diseases. The observed heterogeneity of contacts amongst animals is best captured by full network simulations, although simple compartmental models describe the key features of an outbreak but, as expected, often overestimate the speed of an outbreak. Here the weights of contacts are heterogeneous, with many low weight links. However, due to the well-connected nature of the networks, this has little effect and differences between models remain small. These results indicate that simple compartmental models can be a useful tool for modelling real-world flocks; their applicability will be greater still for more homogeneously mixed livestock, which could be promoted by higher intensity farming practices.     

Emerging diseases: a global and biological perspective

The 'Livestock Revolution' and globalization with enormous increases in free trade of animals and food products are not a choice but a reality (Thiermann, J. Vet. Med. Educ., 28, 2001, 56). Conditions of modern life, some of them related to or being the result of globalization, ensure that factors responsible for disease emergence are more prevalent than ever. Categorization of the factors is somewhat arbitrary but are representative of the underlying processes that cause emergence. Major responsible factors include ecological changes, such as changes due to agriculture or economic development or to anomalies in climates, human demographical changes and behaviour, travel and commerce, technology and industry, microbial adaptation and change, and the breakdown of public health measures (Morse, Emerg. Infect. Dis., 1, 1995, 7). Furtheron, concerning pathogens, their most striking feature emerging and re-emerging is their diversity, ranging from viruses and prions, over bacteria and rickettsia, fungi, protozoa to helminths. As presently the epidemiological perspective does not permit reliable prediction and prevention of most damaging new pathogens, and as the evolutionary perspective only provides rough theoretical estimates for selective processes in pathogen populations, surveillance and monitoring remain the most important methods to recognize early that 'something has happened'. In light of the complexity and diversity of likely new emerging diseases, such surveillance may be more broadly targeted and aimed more realistically at early recognition of disease syndromes rather than at identifying microbial diseases. The complex and rapid-paced development of international trade, coupled with increasing societal demands for not only abundant and inexpensive food as well as for protection from diseases originating from animals, demands immediate attention from the veterinary community. The inter-relationship at the minimum between animal production, animal diseases and human diseases demands that we consider our concepts, methods and structures. There exists a huge growth area for the veterinary profession; substantial need exists for trained individuals who understand the science of foreign diseases, who can facilitate emergency management operations against diseases (Brown, J. Vet. Med. Educ., 30, 2003, 112) and who can contribute to adjust and strategically develop animal production systems further.     

Remote sensing and epidemiology: examples of applications for two vector-borne diseases

Remote sensing techniques have greatly contributed to improve our capacity to observe our environment and its processes. For about 15 years, the use of satellite images for epidemiological purposes has been largely promoted to determine diseases distributions and their variations through time. In some circumstances, when diseases are strongly related to environmental data such as climate, vegetation or land-use, radiation values can be included in prediction models. In other cases, remote sensing data provide information for drawing thematic layers involved in the epidemiological processes, which may differ according to the different ecotypes and ecosystems. According to its final goal, the users can choose from the panel of available radiometers with specific characteristics including spatial resolution and frequency of data. In this paper, two examples of major vector-borne diseases, namely Animal Trypanosomosis and Bluetongue, illustrate these applications.     

Spatial epidemiological approaches to inform leptospirosis surveillance and control: A systematic review and critical appraisal of methods

Leptospirosis is a global zoonotic disease that the transmission is driven by complex geographical and temporal variation in demographics, animal hosts and socioecological factors. This results in complex challenges for the identification of high‐risk areas. Spatial and temporal epidemiological tools could be used to support leptospirosis control programs, but the adequacy of its application has not been evaluated. We searched literature in six databases including PubMed, Web of Science, EMBASE, Scopus, SciELO and Zoological Record to systematically review and critically assess the use of spatial and temporal analytical tools for leptospirosis and to provide general framework for its application in future studies. We reviewed 115 articles published between 1930 and October 2018 from 41 different countries. Of these, 65 (56.52%) articles were on human leptospirosis, 39 (33.91%) on animal leptospirosis and 11 (9.5%) used data from both human and animal leptospirosis. Spatial analytical (n = 106) tools were used to describe the distribution of incidence/prevalence at various geographical scales (96.5%) and to explored spatial patterns to detect clustering and hot spots (33%). A total of 51 studies modelled the relationships of various variables on the risk of human (n = 31), animal (n = 17) and both human and animal infection (n = 3). Among those modelling studies, few studies had generated spatially structured models and predictive maps of human (n = 2/31) and animal leptospirosis (n = 1/17). In addition, nine studies applied time‐series analytical tools to predict leptospirosis incidence. Spatial and temporal analytical tools have been greatly utilized to improve our understanding on leptospirosis epidemiology. Yet the quality of the epidemiological data, the selection of covariates and spatial analytical techniques should be carefully considered in future studies to improve usefulness of evidence as tools to support leptospirosis control. A general framework for the application of spatial analytical tools for leptospirosis was proposed.     

Advances in biosecurity to 2010 and beyond: Towards integrated detection,analysis and response to exotic pest invasions

In order to limit the number and impact of exotic pest invasions, leading-edge technologies must be embraced and embedded within integrated national and international biosecurity systems. Outlined here are recent advances in the detection of exotic pests, and prospects for the early recognition of disease. Applications of new tools are described, using our understanding of the genomes of pathogens and vectors. In addition, the role of mathematical and simulation models to aid both biosecurity planning, and decision making in the face of an epidemic, are discussed, and recent attempts to unify epidemiology and evolutionary dynamics are outlined. Given the importance of emerging diseases and zoonoses, the need to align human and veterinary surveillance within fully integrated systems is underlined.     

Advances in biosecurity to 2010 and beyond: towards integrated detection, analysis and response to exotic pest invasions

In order to limit the number and impact of exotic pest invasions, leading-edge technologies must be embraced and embedded within integrated national and international biosecurity systems. Outlined here are recent advances in the detection of exotic pests, and prospects for the early recognition of disease. Applications of new tools are described, using our understanding of the genomes of pathogens and vectors. In addition, the role of mathematical and simulation models to aid both biosecurity planning, and decision making in the face of an epidemic, are discussed, and recent attempts to unify epidemiology and evolutionary dynamics are outlined. Given the importance of emerging diseases and zoonoses, the need to align human and veterinary surveillance within fully integrated systems is underlined.     

A survey of the transmission of infectious diseases/infections between wild and domestic ungulates in Europe

ABSTRACT: The domestic animals/wildlife interface is becoming a global issue of growing interest. However, despite studies on wildlife diseases being in expansion, the epidemiological role of wild animals in the transmission of infectious diseases remains unclear most of the time. Multiple diseases affecting livestock have already been identified in wildlife, especially in wild ungulates. The first objective of this paper was to establish a list of infections already reported in European wild ungulates. For each disease/infection, three additional materials develop examples already published, specifying the epidemiological role of the species as assigned by the authors. Furthermore, risk factors associated with interactions between wild and domestic animals and regarding emerging infectious diseases are summarized. Finally, the wildlife surveillance measures implemented in different European countries are presented. New research areas are proposed in order to provide efficient tools to prevent the transmission of diseases between wild ungulates and livestock.     

An epidemiological approach to prevention and control of three common heritable diseases in canine pedigree breeds in the United Kingdom

This paper reviews recent epidemiological research in the United Kingdom for controlling deafness in Dalmatians, glaucoma in flat coated retrievers and great Danes and hip dysplasia in flat coated retrievers, Newfoundlands, Gordon setters and Labrador retrievers. These studies assessed the prevalence of the disease, identified the factors affecting prevalence, and developed predictive statistical models of offspring/parent relationships. For each disease/breed combination, the research identified those sires and dams that might justifiably be regarded as suitable/unsuitable as potential parents in a selective breeding strategy to control or prevent the disease. Future progress in the control of these diseases is likely to come from greater understanding of their mode of inheritance. Insight, even for these complex diseases, can be derived from further detailed statistical evaluation of datasets such as those described in this paper.     

流行病学模型及建模步骤

流行病学模型可作为动物疫病风险评估及防控策略制定的有力工具。论文介绍了流行病学模型的定义及其在动物疫病管理决策中的应用,讨论了模型的分类及建模的方法,重点阐述了动物疫病流行病学模型的构建步骤,包括建模系统和研究目标的确定、动物群体和疫病流行病学数据信息的收集、概念模型的构建、概念模型的确认、概念模型的公式化或编程、模型的验证、运行有效性的评估、敏感性分析、执行研究、输出结果的解释和交流。提出了一些建模的基本准则和应该着重考虑的问题,以期为动物疫病流行病学模型和风险评估预警研究提供参考。     

A global livestock production and health atlas (GLiPHA) for interactive presentation,integration and analysis of livestock data

An interactive electronic atlas has been developed with the purpose of providing a scaleable overview of spatial and temporal variation in animal production and health-related information for decision and policy makers in national and international institutions. The information contained in the atlas is currently managed and presented using the Key Indicators Mapping System (KIMS), and will also be integrated using the Key Indicators Database System (KIDS). Both systems were developed by the World Agricultural Information Centre of the FAO (FAO-WAICENT), the former as a stand-alone application and the latter for access via the Internet. Components of the atlas include vector maps, livestock disease and production databases, rules for country-level disease risk classification and 'disease cards' containing basic background information on diseases included in the atlas. The disease data is currently based primarily on Office International des Epizooties (OIE) disease reports, and the livestock production data on the FAO-WAICENT database. The atlas is highly interactive and allows visual presentation of information using maps, tables and charts. It also contains links to relevant resource information on the Internet. Diseases covered in the animal health layer include most OIE List A diseases and a subset of OIE List B diseases. Extensive analyses have been conducted to develop a set of qualitative and semi-quantitative criteria that allow improved disease status classifications based on 5-years cumulative OIE disease reports, and official disease control declarations. Classification rules were determined depending on the epidemiological features of each disease and considering spatial heterogeneity of disease presence in local regions.     

Analysis of correlated discrete observations: background,examples and solutions

The goal of this paper is to highlight the use and interpretation of statistical techniques that account for correlation in epidemiological data. A conceptual statistical background is provided, and the main types of regression models for correlated data are highlighted. These models include marginal models, random effect models and transitional regression models. For each model type an example with data from the veterinary literature is provided. The examples are specifically used to highlight estimation procedures for parameters, and the interpretation of the estimated parameters. This paper emphasizes that statistical techniques and software to fit them are more widely available now, but that parameters have different interpretations in different model types. Consequently, we stress the importance of focusing on choosing the most appropriate model for the specific purpose of the analysis.     

Future challenges of disease in the beef cattle industry

Disease control must be part of the management system in any beef cattle enterprise where improved net returns are a constant goal. A current view of the importance of disease is reflected in the research portfolio of the Australian Meat and Live-stock Research and Development Corporation (AMLRDC), where only 14% of projects relate to cattle health problems. Our relative freedom from epidemics is partly responsible for this balance, but the profession should continue to be alert to the range of actual or potential threats to the national herds and those predisposing factors, both managerial and environmental, that influence their effects. In Australia with its crucial beef export component, several priority areas can be identified. They are (i) completion of the Brucellosis and Tuberculosis Eradication Campaign (BTEC) (ii) improved knowledge of the effects of production of subclinical disease including deficiency states (iii) better understanding of the infertility complex from conception to birth. Congenital viral infections such as mucosal disease and the arbovirus group are slowly emerging from their epidemiological obscurity (iv) constant awareness of the potential threat of exotic diseases and defensive methods available to meet them. There is a particular need to understand the epidemiology of the large tropical cattle herd, which interfaces with South-East Asia. Our comparative freedom from epidemics should not cause any relaxation of vigilance by the veterinary services in the private or public sectors. Nor should government be allowed to minimise the critical role of the veterinary profession in our defense against animal disease (v) increased liaison with our trading partners in livestock exports.(ABSTRACT TRUNCATED AT 250 WORDS)     

重庆主要育苗场柑橘疫病及危险性病毒病发生情况调查

检疫性病害和病毒病是阻碍柑橘安全生产的重要因素。重庆自2007年启动柑橘非疫区项目建设以来,建立完善了全市柑橘疫情监测预警网络,尤其是对柑橘黄龙病、溃疡病的阻截防控成效显著,但目前部分育苗企业对柑橘病毒病的为害仍然认识不足。为此,本研究于2017年对重庆市柑橘母本园,一级采穗圃、二级采穗圃和5个主要的柑橘育苗单位的1373株母本树和采穗母树进行了检疫性病害和危险性病毒病的抽样调查,结果显示,上述苗木繁育单位的采穗母树都没有感染柑橘溃疡病和黄龙病等检疫性病害,也没有检测出褪绿矮化病、鳞皮病等危险性病毒病,但黄脉病和叶斑驳病等新发柑橘病毒病发生较为严重,需要引起重视。本研究的结果将为重庆柑橘产业的持续、健康发展提供重要保障。