Contagious Animal Diseases Research Articles

Eradication of foot-and-mouth disease: a foot in mouth proposition.

Foot-and-mouth disease (FMD) is the most contagious disease of cloven-hoofed animals. The disease is highly infectious and is characterized by rapid transmission, a sequel to the rather explosive growth cycle of the causative virus, FMDV (an aphthovirus; Picornaviridae). As few as 10–25 virus particles can establish air-borne infection in domestic ruminants and pigs. The latter emit the greatest amounts of virus as aerosols. In unvaccinated herds mortality can be high, particularly in young cattle and pigs. Milk production ceases and animals used for traction can become useless. Internationally agreed policy dictates that once a country has adopted an eradication strategy, all animals on affected farms must be destroyed. In areas where the disease occurs, trade of livestock and animal products must be blocked, and a wide range of agricultural products may be banned from export to other countries.

Risk and risk management in agriculture: an overview and empirical results

The paper gives an overview of sources of risk and risk management strategies in agriculture. As risk is an inescapable fact of life, in particular in agriculture, farmers must try to manage risk effectively. Risk management is an integral part of good management of a farm, being a way to avoid losses and exploit opportunities. Results of a field survey with 731 Dutch livestock farmers are presented which indicate that contagious animal diseases and the death of the farm operator are the major sources of risk for livestock farmers. Furthermore, producing at the lowest costs and buying insurance are the most important risk management strategies.

Brucellosis in Saudi Arabia: Past, Present and Future

Brucellosis in Saudi Arabia: Past, Present and Future

Assessing the risk of wind-borne spread of foot-and-mouth disease in Australia

The effect the environment has on the spread of animal disease depends on the particular disease and can vary from being minor to being almost the sole determinant. An assessment of the risk of a particular disease outbreak and its consequences must combine the epidemiology of the disease with the variability of the environment. Foot-and-mouth disease is a highly contagious animal disease that spreads readily by close contact with infected animals and infected product. For such spread, the environment has little consequence. However, occasionally, wind-borne viral particles can spread the disease considerable distances. This paper concentrates on the methods used in a study undertaken to assess the potential for the wind-borne spread of foot-and-mouth disease under Australian conditions. The conditions suitable for the virus to persist as an aerosol, the amount of virus produced during an outbreak, and the dose-response to wind-borne virus were determined by considering the epidemiology of the disease. Environmental components considered included an analysis of weather records and livestock distribution data to identify areas at risk, and the use of a Gaussian plume model to estimate the extent of spread.

A rapid chromatographic strip test for the pen-side diagnosis of rinderpest virus

Rinderpest is a contagious viral disease of cloven-hoofed domestic and wild animals. Eradication of the virus following outbreaks depends on rapid and accurate diagnosis of infection and the implementation of control measures. Reporting and confirmatory diagnosis precede the implementation of control measures. A number of techniques have been used for diagnosis such as agar gel immunodiffusion, enzyme-linked immunosorbent assay (ELISA), molecular biological techniques such as polymerase chain reaction (PCR) and virus isolation in tissue culture. Many of these methods are both time consuming and require skilled personnel. The development of a rapid pen-side test for the detection of rinderpest virus (RPV) antigen in lachrymal fluid of cattle is described using the Clearview™ chromatographic strip test technology (Unipath, Bedford). Optimum conditions for binding monoclonal antibody to nitrocellulose and latex microspheres were determined and a prototype device was developed. The device detected viral antigen in lachrymal fluids from experimentally and naturally infected cattle and showed no cross-reactivity with other related viruses. A field trial was carried out at the Landhi Cattle Colony (LCC), Pakistan, to assess the performance of the rinderpest test under field conditions. Ninety-seven animals, some of which were showing various clinical signs, at LCC and neighbouring colonies were sampled and tested at the pen-side by Clearview™ and later by immunocapture ELISA (IC-ELISA) at IAH, Pirbright. Nineteen animals were positive by Clearview™ and/or IC-ELISA. Seventeen out of 19 rinderpest positive animals were positive by Clearview™ and 15 out of 19 were positive by IC-ELISA. Reverse transcription polymerase chain reaction (RT-PCR) confirmed the 19 animals to be rinderpest positive. This simple, rapid, specific test allows for the first time, accurate pen-side diagnosis of rinderpest.

Localization of foot-and-mouth disease virus RNA by in situ hybridization within bovine tissues

Foot-and-mouth disease is a highly contagious disease of cloven hooved animals. In cattle, both acute and long-term persistent infections occur. Foot-and-mouth disease virus (FMDV), a picornavirus, has been shown, using virus isolation procedures, to replicate in the pharynx and soft palate of cattle. In this study, in situ hybridization has been used to detect FMDV RNA within the cells of tissues removed from infected bovines. A digoxigenin-labelled anti-sense RNA probe was prepared corresponding to a region of the FMDV genome encoding part of the RNA-dependent RNA polymerase (3D). The efficacy and specificity of this probe for in situ hybridisation was determined using virus-infected cells in tissue culture. Strong cytoplasmic staining was only detected in FMDV-infected cells. Various tissue samples were collected from FMDV-infected cattle between 5 and 17 days post-infection. Viral RNA was detected by in situ hybridisation within cells of the soft palate, tonsil and pharynx up to 17 days post-infection. This technique is useful for the study of FMDV localization in cattle both during and after the acute clinical phase of disease and may assist in identifying specific sites of virus persistence.

The involvement of the agriculture industry and government in animal disease emergencies and the funding of compensation in western Europe.

In Western Europe, the control and eradication of contagious animal diseases have always been subject to government legislation. In the event of an outbreak, the principal policy is 'stamping-out' (depopulation) of the infected herd. The owner of the herd is usually awarded financial compensation. The authors provide an overview of the involvement of the agriculture industry and government in animal disease emergencies and the funding of compensation in Western Europe. In particular, developments within the European Union are described, as illustrated by a case study in the Netherlands. The economic consequences of a widespread epidemic of classical swine fever (hog cholera) in the Netherlands in 1997 are described. Evaluation of the epidemic demonstrated that special emphasis needs to be placed on factors such as the high-risk period, animal movement, the attitude of farmers towards risk and the structure of compensation. Epidemic disease insurance schemes are considered to be a possible alternative in alleviating certain financial losses caused by disease outbreaks.

Irreversible decision making in contagious animal disease control under uncertainty: an illustration using FMD in Brittany

The concept of irreversible investment is applied to highly contagious animal disease control when uncertainty about the spread of the disease is resolved over time. In comparison with the strategy of destroying infected herds, the vaccination programme causes additional losses that cannot be recovered. These sunk costs are thus irreversible. Therefore, the gain from waiting for new information, namely the quasi-option value, should induce animal health authorities to delay the decision to vaccinate if the probability of a widespread epidemic is not too high. A numerical example is developed for foot and mouth disease (FMD) in Brittany. Keywords:contagious animal disease, irreversible control strategy, foot and mouth disease, gain from waiting

Bovine viral vaccines, diagnostics, and eradication: Past, present, and future

This chapter discusses past, present, and future of bovine viral vaccines, diagnostics, and eradication. Foot-and-mouth disease (FMD) virus (FMDV) has been eradicated from the Western world. In the recent past, various European countries have become free of bovine herpesvirus 1 (BHV1), which causes infectious bovine rhinotracheitis (IBR) and pustular vulvovaginitis (IPV). Other countries have eradication schemes implemented for this virus. Recently, in the Scandinavian countries, programs have been started with the aim of eradicating bovine virus diarrhea (BVD) virus (BVDV) and in the future other European countries may follow this example. These three bovine viral diseases are used to illustrate the evolution in vaccines and diagnostics in relation to eradication. FMD is among the most contagious viral diseases of cloven-hoofed animals and is causing enormous economic losses. The virus belongs to the genus Aphtovirus of the family Picornaviridae and consists of seven serotypes, A, O, C, SAT 1, SAT 2, SAT 3, and Asia 1, that do not cross-protect.

Introduction of contagious animal diseases into The Netherlands: elicitation of expert opinions

This paper describes an experiment aimed at the derivation of information on Foot-and-Mouth Disease, Classical and African Swine Fever, Swine Vesicular Disease, Newcastle Disease and Avian Influenza to be used in an economic model to simulate introduction of a virus into the Netherlands. Several elicitation techniques, including three-point estimation, Conjoint analysis and ELI were used in the experiment. Three-point estimation (asking for minimum, most likely, and maximum values) was used to derive information concerning the length of the High Risk Period (HRP), during which the virus may spread freely. Conjoint analysis is widely used in marketing and consumer science and was used in this experiment to elicit the relative importance of risk factors which may introduce disease into the Netherlands (such as import of livestock, import of animal products, etc.). The ELI-technique (ELIcitation of uncertain knowledge) originates from the area of mathematical psychology and was used to derive information on the expected number of outbreaks of the diseases under consideration in European countries. The experiment was conducted with 43 (out of 50) invited people, all involved in or related to disease control in one way or another. The participants expected, for all diseases, the longest HRP in countries of eastern Europe. Import of livestock was evaluated as the most important risk factor for all diseases under consideration. Most outbreaks within the next five years were expected to occur in countries of eastern Europe, the smallest number in the Netherlands and the Scandinavian countries. Results especially showed that Conjoint analysis and ELI are useful tools to help quantify subjective knowledge. These subjective elicitation methods may not reveal the `Golden Standard' but as long as `objective' predictive information is not available, use of these tools may be valuable to enhance quality of input and output of economic simulation models to support policy-making in the prevention and control of contagious animal diseases.

Eliciting the relative importance of risk factors concerning contagious animal diseases using conjoint analysis: a preliminary survey report

Conjoint analysis is a technique well known in marketing research to elicit consumer preferences and opinions. This paper describes the results of an experiment which explores the potential application of conjoint analysis in the field of veterinary epidemiology and economics. In this experiment, the method of conjoint analysis was used to elicit the opinion of experts about the relative importance of risk factors concerning contagious animal diseases. Diseases studied were: African Swine Fever (ASF), Classical Swine Fever (CSF), Foot-and-Mouth Disease (FMD), Swine Vesicular Disease (SVD), Newcastle Disease (NCD) and Avian Influenza (AI). Risk factors included were import of livestock, import of animal products, feeding of swill, tourists, returning livestock trucks and air. The conjoint analysis technique was used to draw up a questionnaire which was handed out during the 7th ISVEE held at Nairobi, Kenya, from 15 to 19 August 1994. According to the experts approached, the factors ‘import of livestock’ and ‘import of animal products’ were the major sources of risk for all diseases. For ASF, CSF and FMD, the risk factor ‘swill feeding’ ranked third. For FMD and the two poultry diseases NCD and AI, only the risk factor ‘air’ was important. Overall conclusion was that conjoint analysis could be a useful method for eliciting the opinion of experts about risk factors concerning contagious animal diseases. In further research, special attention should be given to the selection of experts and the presentation of the conjoint questions.

Outline for an integrated modelling approach concerning risks and economic consequences of contagious animal diseases

Management decisions on control of major infectious animal diseases may have a large impact, but are usually based on scarce and unreliable information. An integrated model which combines the various aspects of outbreaks and risks with economic consequences has yet to be developed. A flexible model with the possibility of evaluating the consequences of various strategies would be an important tool to aid in policy and decision making. In this paper a modelling approach is proposed which should lead to such an integrated model. The approach (a general framework) is outlined and several techniques to be applied are discussed. Subjective mathematical probability seems to be an appropriate technique as a basis for the model. In developing the model, special emphasis should be given to gathering the input data, which could include the use of expert panels. Promising techniques to deal with expert panels mainly originate from the area of marketing and consumer science and include conjoint analysis and the elicitation of subjective probability distributions.

National identification and recording systems for contagious animal disease control

Abstract A conceptual framework was described for national identification and recording (I&R) systems, especially referring to the role in the control of highly contagious diseases in pigs. Subsequently, four different concepts of I&R systems were described: a current system meeting EU minimum standards, a revised system that will be introduced in several countries in the near future and two future concepts, based on electronic identification and monitoring. These concepts were discussed from the perspective of (1) their role in disease prevention and control, and (2) the impact of additional applications of these systems on animal production. It was concluded that improvement of the current I&R system can be beneficial to contagious disease control. Moreover, electronic identification and monitoring systems could be an especially important tool in improving collection and subsequent utilisation of information in future animal production. The additional applications would also be very valuable in increasing the economic feasibility of these systems.

EpiMAN: Decision Support System for Contagious Animal Disease Control

Contagious animal disease outbreaks are of great economic importance and, therefore, require rapid identification and eradication. Computerized decision support systems can be of help in the operational management of the outbreak control, e.g. to manage the vast amount of data and to help set the correct priorities. A system is presented (named EpiMAN) which is under development for use in the European Union, and based on one developed in New Zealand. The system consists of a database management system, a geographic information system, simulation models and expert systems. The system can also be used in policy development and as a training and research tool.

Risk attitude and decision making in contagious disease control

Accurate control of contagious animal diseases is of major concern for most countries. Basic and advanced decision rules are presented and applied, to show the impact of various risk attitudes of decision makers in determining what control strategy to choose, taking Foot-and-Mouth disease control in the Netherlands as an example. The choice appears to vary considerably among the decision rules (i.e. risk attitudes). Eventually, it is up to the decision maker to decide what rule is the most appropriate. Insight into the potential consequences of the various alternatives may contribute towards a more thoughtful approach in this respect.

Le rôle de l'Office International des Epizooties dans la protection de la santé des mammifères en liberté

The various activities undertaken by the Office International des Epizooties (OIE) since 1924 to protect the helth of free-ranging mammals are outlined and discussed. Two types of activity have been conducted over the years: --The first type promotes measures to protect the health of free-ranging mammals in order to safeguard the health of domestic animals and human beings. These measures have prevented the propagation of the highly contagious diseases of animals and the more serious zoonoses. --The second type aims at protecting the health of free-ranging mammals in order to maintain the fauna and the natural equilibrium. Ecological and epidemiological studies are promoted with a view to effective management of wildlife populations and overcoming the associated health risks. By virtue of its close contacts with officials in charge of animal health in 126 Member Countries, the OIE has made a noteworthy contribution to the protection of populations of free-ranging mammals.

Organisation of veterinary public health activities in countries of the Eastern Mediterranean region.

This review covers the organisation of veterinary public health (VPH) activities in countries of the Eastern Mediterranean region, with reference to zoonoses and hazards to man from foods of animal origin. A study of the region shows that no separate VPH units exist within the national Veterinary Services. Although these Services are gradually being upgraded and strengthened, most of their resources are spent in controlling serious contagious animal diseases such as foot and mouth disease, rinderpest and Newcastle disease. Rabies, present in almost every country of the region, is a zoonosis which no Veterinary Service can ignore. Other serious zoonoses affecting the region include echinococcosis, brucellosis, leishmaniasis, anthrax, toxoplasmosis and tuberculosis. Salmonellosis is one of the most serious food-borne zoonoses, while hazards from the increased presence of additives, pesticides, antibiotics and hormones in foods of animal origin are other emerging VPH problems. Many obstacles hamper efficient reorganisation of VPH activities. These include the inherited colonial system of assigning VPH activities to other authorities (health inspectors) rather than to Veterinary Services; the confusion as to which authority should actually be responsible in a given field; the lack of epidemiological studies and knowledge of the real extent of VPH problems; lack of training; inadequately staffed and poorly equipped Veterinary Services; and lack of public awareness. Nonetheless, a few countries have made excellent progress in reorganising VPH activities and in eradicating serious zoonoses. International organisations like the OIE, FAO and WHO can help greatly in establishing efficient VPH programmes.

Contagious diseases of animals.

Contagious diseases of animals.

British Food Journal Volume 30 Issue 7 1928

British Food Journal Volume 30 Issue 7 1928

International Agreement for the Creation at Paris of an International Office for Dealing with Contagious Diseases of Animals

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