Application of subjective methods to the determination of the likelihood and consequences of the entry of foot-and-mouth disease into New Zealand

New Zealand has a history of continuous freedom from foot-and-mouth disease and relies on a two-tier system of surveillance to maintain this status. The first involves border control procedures and stringent importation standards, and the second is an exotic disease and pest response programme. As part of an economic evaluation comparing the exotic disease and pest response programme against a hypothetical lower grade ;measured response programme subjective judgements of the risks involved were required. Twenty-eight selected animal health professionals, predominantly veterinarians, were posted a questionnaire that used three techniques (single point estimates, three point estimates and elicitation methods) to determine the risk components in a foot-and-mouth disease outbreak. The two key variables were the probability of an outbreak in New Zealand, and the number of secondary properties to which the disease spread during the epidemic. A Delphi conference of ten selected participants then focused mainly on the two key variables, with a second round postal extension to this group for the first variable. The individual data sets were then analysed and combined using a stochastic simulation technique. The final mean probability of an outbreak was about once in 50 years (0.0199). The mean numbers of farms to which disease would spread during an epidemic under the existing exotic disease and pest response programme, a measured response programme which allowed vaccination and a measured response programme which excluded vaccination were estimated to be 61, 478 and 2230 respectively. The policy implications arising from the quantification of these two key variables are that more expenditure on preparedness is justifiable and current resource planning is barely adequate.     

Application of subjective methods to the determination of the likelihood and consequences of the entry of foot-and-mouth disease into New Zealand

New Zealand has a history of continuous freedom from foot-and-mouth disease and relies on a two-tier system of surveillance to maintain this status. The first involves border control procedures and stringent importation standards, and the second is an exotic disease and pest response programme. As part of an economic evaluation comparing the exotic disease and pest response programme against a hypothetical lower grade “measured response programme” subjective judgements of the risks involved were required. Twenty-eight selected animal health professionals, predominantly veterinarians, were posted a questionnaire that used three techniques (single point estimates, three point estimates and elicitation methods) to determine the risk components in a foot-and-mouth disease outbreak. The two key variables were the probability of an outbreak in New Zealand, and the number of secondary properties to which the disease spread during the epidemic. A Delphi conference of ten selected participants then focused mainly on the two key variables, with a second round postal extension to this group for the first variable. The individual data sets were then analysed and combined using a stochastic simulation technique. The final mean probability of an outbreak was about once in 50 years (0.0199). The mean numbers of farms to which disease would spread during an epidemic under the existing exotic disease and pest response programme, a measured response programme which allowed vaccination and a measured response programme which excluded vaccination were estimated to be 61, 478 and 2230 respectively. The policy implications arising from the quantification of these two key variables are that more expenditure on preparedness is justifiable and current resource planning is barely adequate.     

The Potential Economic Impact of an Outbreak of Foot-and-Mouth Disease in Canada

The possibility of an outbreak of foot-and-mouth disease is of concern to Canada's livestock industry due to the resulting economic consequences. The primary economic impact of a foot-and-mouth disease outbreak would arise from the trade embargo placed on Canadian exports of animals and animal products to countries free of the disease. Agriculture Canada's Food and Agriculture Regional Model was used to estimate the economic impact of such a trade embargo. Two scenarios, a small and large outbreak, were simulated over a five year period (1986-90). The results indicate that even a small outbreak of foot-and-mouth disease would have serious economic consequences for the livestock sector with farm cash receipts declining by $2 billion. The largest impact would be on the pork sector followed by the beef sector.     

Investigation of an outbreak of foot-and-mouth disease in vaccinated dairy cattle in Thailand

SUMMARY An outbreak of foot-and-mouth disease that spread between two related vaccinated dairy herds was investigated. Although the cattle were of similar vaccination status, in one herd there was high morbidity, whereas in the other there was considerably lower morbidity. The relationship between the vaccine virus and the outbreak virus was expressed as an r value determined by the two-dimensional neutralisation test. Bovine serum homologous to the vaccine virus indicated a close antigenic relationship between the vaccine virus and the outbreak virus (r = 0.61). The source of the outbreak virus was not determined. The investigation suggested a requirement for close contact between stock for foot-and-mouth disease to spread in a tropical environment, in contrast to the capacity of the disease to spread considerable distances by aerosol transmission in temperate climates.     

Modelling the spread of foot-and-mouth disease in Australia

Preparedness for an incursion of an exotic animal disease is of key importance to government, industry, producers and the Australian community. An important aspect of Australia's preparedness for a possible incursion of foot-and-mouth disease is investigation into the likely effectiveness and cost-efficiency of eradication strategies when applied to different regional outbreak scenarios. Disease modelling is a tool that can be used to study diseases such as foot-and-mouth disease to better understand potential disease spread and control under different conditions. The Australian Government Department of Agriculture, Fisheries and Forestry has been involved with epidemiologic simulation modelling for more than 10 years, and has developed a sophisticated spatial model for foot-and-mouth disease (AusSpread) that operates within a geographic information system framework. The model accommodates real farm boundary or point-location data, as well as synthesised data based on agricultural census and land use information. The model also allows for interactions between herds or flocks of different animal species and production type, and considers the role that such interactions are likely to play in the epidemiology of a regional outbreak of foot-and-mouth disease. The user can choose mitigations and eradication strategies from those that are currently described in Australia's veterinary emergency plan. The model also allows the user to evaluate the impact of constraints on the availability of resources for mitigations or eradication measures. Outputs include a range of maps and tabulated outbreak statistics describing the geographic extent of the outbreak and its duration, the numbers of affected, slaughtered, and, as relevant, vaccinated herds or flocks, and the cost of control and eradication. Cost-related outputs are based on budgets of the value of stock and the cost of mitigations, each of which can be varied by the user. These outputs are a valuable resource to assist with policy development and disease management.     

抗口蹄疫病毒策略研究进展

口蹄疫是偶蹄动物的一种烈性传染病,可使世界范围内的畜牧业遭受严重的经济损失。该病的防控方法主要包括扑杀、销毁病畜及其同群动物,对疫区内其它易感畜群和受威胁区的易感动物立即紧急接种对应型号的口蹄疫疫苗,除此之外,还需要有一些新的紧急抗病毒策略来弥补疫苗的不足,从而为易感动物及未感染动物提供及时的保护,作者着重综述了抗口蹄疫病毒策略的研究进展,主要包括IFN的应用、反义技术的应用、RNA干扰技术的应用三方面内容。     

The epidemiology of foot-and-mouth disease: implications for New Zealand

Foot-and-mouth disease is an acute, highly communicable disease affecting cloven-hoofed animals, both domesticated and wild. It may well be the most contagious disease known in the animal kingdom. The key features that contribute to this include its ability to gain entry and initiate infection through a variety of sites, the small infective dose, the short incubation period, the release of virus before the onset of clinical signs, the massive quantities of virus excreted from infected animals, its ability to spread large distances due to airborne dispersal, and the persistence of the virus in the environment. These features, plus the ability of the virus to be disseminated through the movements of animals, animal products, people, and plant and equipment makes the disease very difficult to control. New Zealand has never experienced a foot-and-mouth disease epidemic, and the economic consequences of an outbreak would be disastrous, due to the eradication costs, the loss of productivity and the impact on the export of animals and animal products. The smuggling of meat products, embryos or semen into the country are perceived as the most likely ways in which the disease could be introduced. The New Zealand Ministry of Agriculture and Fisheries therefore operates a two-tier system of defense against foot-and-mouth disease. The first tier involves border protection through stringent import controls to prevent the entry of infectious material. If this barrier is breached, an emergency response programme is activated, involving a stamping-out eradication strategy. This paper attempts to draw on overseas historical outbreak experiences and research findings to gain insights into the epidemiology of foot-and-mouth disease as it would relate to New Zealand.     

Residual foot-and-mouth disease virus antibodies in French cattle and sheep six years after the vaccination ban

A serological survey was carried out on French cattle to establish a reference pattern of residual vaccine antibodies and non-specific reactions against the foot-and-mouth disease virus 6 years after the ban on vaccination and in the absence of any foot-and-mouth disease outbreak. Most of the multi-vaccinated cattle still displayed high titres of antibodies and up to 50% of those which had received a single injection still had antibodies. Non-specific reactors were also recorded among animals born during and after 1991. Most of them displayed low titres close to the threshold. Sheep were also tested and, as for cattle, 4.6% of non-specific reactors were recorded, with titres close to the threshold for two-thirds of them. As part of these animals have been resampled and retested, sera revealed negative confirming that these animals are true non-specific reactors. Serological testing as a mean of FMD control should take these facts into account.     

Foot-and-mouth disease eradication efforts in the Republic of Korea

On March 20, 2000, a suspected vesicular disease in cattle was reported to the National Veterinary Research and Quarantine Service (NVRQS) of the Republic of Korea. This represented the index case of a foot-and-mouth disease (FMD) outbreak, which spread through several provinces. The Republic of Korea had been free of FMD for 66 years prior to the reintroduction of the virus and had recently suspended imports of pork and pork products from neighboring Japan owing to a reported FMD outbreak in that country. The Korean outbreak was ultimately controlled through the combination of preemptive slaughter, animal movement restrictions, and a strategy of ring vaccination. The purpose of this paper is to review the current FMD situation in Korea in the aftermath of its 2000 epizootic and how it may affect future efforts to eradicate or reduce risk of reintroduction of the disease into Korea.     

Utilizing qualitative methods in survey design: examining Texas cattle producers' intent to participate in foot-and-mouth disease detection and control

The effective control of an outbreak of a highly contagious disease such as foot-and-mouth disease (FMD) in the United States will require a strong partnership between the animal agriculture industry and the government. However, because of the diverse number of economic, social, and psychological influences affecting livestock producers, their complete cooperation during an outbreak may not be assured. We conducted interviews with 40 individuals involved in the Texas cattle industry in order to identify specific behaviors where producer participation or compliance may be reduced. Through qualitative analysis of these interviews, we identified specific factors which the participants suggested would influence producer behavior in regard to FMD detection and control. Using the Theory of Planned Behavior (TPB) as an initial guide, we developed an expanded theoretical framework in order to allow for the development of a questionnaire and further evaluation of the relative importance of the relationships indicated in the framework. A 2-day stakeholder workshop was used to develop and critique the final survey instruments. The behaviors which we identified where producer compliance may be reduced included requesting veterinary examination of cattle with clinical signs of FMD either before or during an outbreak of FMD, gathering and holding cattle at the date and time requested by veterinary authorities, and maintaining cattle in their current location during an outbreak of FMD. In addition, we identified additional factors which may influence producers' behavior including risk perception, trust in other producers and regulatory agencies, and moral norms. The theoretical frameworks presented in this paper can be used during an outbreak to assess barriers to and social pressures for producer compliance, prioritize the results in terms of their effects on behavior, and improve and better target risk communication strategies.     

口蹄疫的特点以及规模化猪场生物安全体系构建

近年来,猪的口蹄疫疫情时有发生,面对具有高度传染性的疫病,尤其在国内规模化、集约化的养殖场中,一旦发生疫情不利于控制,极易造成疫情大范围暴发,因此采取必要的预防和控制措施仍然是关键所在.本文以口蹄疫为例,简述口蹄疫的特点,并通过选址与布局、生产管理、可移动风险和疫病防控等4个方面,阐明构建猪场生物安全体系是防控疫病的重...     

Estimating the risk of importation of foot-and-mouth disease into Europe

The opinions of a number of recognised world experts on foot-and-mouth disease (FMD) were sought in order to answer key questions relating to the importation of the disease into European countries from countries outside Europe. In addition, their opinions were sought on where in Europe a primary outbreak of FMD was most likely to occur and the number of outbreaks likely to occur within European countries in the next five years. The Balkans group of countries was considered to be the most likely group within Europe to have a primary outbreak of FMD and also most likely to have the highest number of primary outbreaks. Turkey was considered to be the country outside Europe which was most likely to be the source of an outbreak within Europe as a whole, and the illegal importation of livestock was considered to be the most likely route of introduction of FMD into Europe. Results specific to the Islands group of countries, which included the UK and Ireland, suggested that this group was likely to have a mean of one primary outbreak of FMD in the five years from September 2000, and that the importation of foodstuffs by people entering those countries from Turkey was the most likely source of an outbreak.     

Re-emergence of foot-and-mouth disease in Botswana

The re-emergence of foot-and-mouth disease (FMD) in Botswana is reported. The disease outbreak occurred in the Matsiloje Extension Area of Francistown veterinary district situated in the northeastern part of the country in an Office International des épízooties (OIE) recognized FMD free zone without vaccination. The disease affected cattle only and did not spillover into sheep and goats resident in the same extension area, as demonstrated by lack of seroconversion to FMD when tested. The virus isolate associated with the outbreak was identified as FMD virus; Southern African Territories (SAT) type SAT-2. The disease outbreak is discussed in relation to FMD outbreaks that have occurred previously within and outside Botswana.     

Evaluation of the application of veterinary judgement in the pre-emptive cull of contiguous premises during the epidemic of foot-and-mouth disease in Cumbria in 2001

This paper presents a detailed analysis of the application of contiguous culling in Cumbria between May 1 and September 30, during the outbreak of foot-and-mouth disease in 2001. The analysis shows that the application of veterinary risk assessment and judgement identified and removed groups of susceptible stock which were at risk of direct transmission of infection and avoided infected animals being left that might have spread the disease. When compared with an automatic contiguous cull, fewer culls were made and some of these were reduced in scale, providing economies in the use of resources. The data suggest that farms contiguous to an infected premises faced a 5 per cent risk of infection by direct transmission and a 12 per cent risk of infection by indirect transmission.     

Veterinary medicine in the media society--science and media in relation to FMD

The outbreak and explosive spread of foot-and-mouth disease in the European Union brought about an intense discussion in the media. FMD was an outstanding media topic in Germany. But the scientific experts of veterinary medicine had no prominent role in this public debate. The reason for this fact seemed to be a lack of competence to present themselves and their knowledge in the media arena. The scientists should try to fit themselves in the media society by training their communication competence.     

Factors associated with the early detection of foot-and-mouth disease during the 2001 epidemic in the United Kingdom

An essential objective of an effective foot-and-mouth disease (FMD) eradication campaign is to shorten the infectious period by rapidly detecting and destroying cases of disease. The purpose of our investigation was to identify factors associated with the early detection of clinical FMD during the 2001 outbreak in the United Kingdom. We performed a logistic regression analysis, using early versus late detection of disease as the outcome of interest.During the 2001 FMD outbreak in the United Kingdom, infected premises were more likely to be detected early under the following circumstances: 1) cattle (particularly dairy) were infected rather than sheep; 2) a recently confirmed infected premises was within 3 km of the new case; and 3) the case was initially reported by the farmer, rather than a Local Disease Control Centre-initiated surveillance activity (patrol, tracing, pre-emptive cull). Our findings suggest that reporting by farmers and initiatives that increase farmer education and awareness should be encouraged.     

Characterisation of a SAT-1 outbreak of foot-and-mouth disease in captive African buffalo (Syncerus caffer): clinical symptoms, genetic characterisation and phylogenetic comparison of outbreak isolates

African buffalo (Syncerus caffer) play an important role in the maintenance of the SAT types of foot-and-mouth disease (FMD) in southern Africa. These long-term carriers mostly become sub-clinically infected, maintaining the disease and posing a threat to other susceptible wildlife and domestic species. During an unrelated bovine tuberculosis experiment using captive buffalo in the Kruger National Park (KNP), an outbreak of SAT-1 occurred and was further investigated. The clinical signs were recorded and all animals demonstrated significant weight loss and lymphopenia that lasted 100 days. In addition, the mean cell volume and mean cell haemoglobin values were significantly higher than before the outbreak started. Virus was isolated from several buffalo over a period of 167 days post infection and the molecular clock estimated to be 3 × 10⁻⁵ nucleotide substitutions per site per day. Seven amino acid changes occurred of which four occurred in hypervariable regions previously described for SAT-1. The genetic relationship of the outbreak virus was compared to buffalo viruses previously obtained from the KNP but the phylogeny was largely unresolved, therefore the relationship of this outbreak strain to others isolated from the KNP remains unclear.     

Vaccination against foot-and-mouth disease: the implications for Canada

Vaccination of susceptible animals against foot-and-mouth disease (FMD) is a well established strategy for helping to combat the disease. Traditionally, FMD vaccine has been used to control a disease incursion in countries where the disease has been endemic rather than in countries considered free of the disease. In 2001, the use of vaccine was considered but not implemented in the United Kingdom (1), whereas vaccine was used to help to control FMD in The Netherlands (2,3). Canadian contingency plans provide for the use of vaccine; Canada is a member of the North American Foot-and-Mouth Disease Vaccine Bank, which could supply vaccine if needed. This article explains why Canada might use FMD vaccine to combat an outbreak and the factors that are relevant to the disposal of vaccinated animals and their products. It concludes that vaccination is an important mechanism in Canada's preparedness for an outbreak of FMD and that products from vaccinated animals are safe for human consumption.     

Temporal-spatial epidemiology of foot-and-mouth disease outbreaks in Mongolia, 2000 – 2002

Prior to 2000, foot-and-mouth disease (FMD) had not been observed in Mongolia since 1973; however, between April 2000 and July 2002, Mongolia reported 44 FMD outbreaks that affected cattle, sheep, goats, and camels. The objectives of this study were to describe the distributions of the 44 reported FMD outbreaks in Mongolia and to assess their spatial clustering and directions of movement. Official reports were collected to obtain the number and species of animals both affected and at risk, and the date and geographical coordinates of each outbreak. Significant global and local spatial clusters of reported FMD outbreaks were identified. Disease spread during the second epidemic moved 76° northeast and the spread of the disease during the third epidemic moved 110° northwest. FMD outbreaks were clustered intensely close to other FMD-positive counties. These findings can be used in the future to help plan prevention and control measures in high risk areas.