Interventional clinical trial on mitigating endemic fluorosis in pregnant and lactating ewes with Spirulina platensis and its impact on lamb production traits.

This interventional clinical trial aimed to assess the potential impact of Spirulina platensis supplementation on pregnant and lactating ewes living in a Moroccan endemic fluorosis area. Forty-eight ewes were divided into four equal groups: Groups I and II served as controls belonging respectively to fluorosis-free and endemic fluorosis areas, Groups III and IV received respectively 250 and 500 mg*kg-1 BW/day of S. platensis, during late pregnancy and early lactation. The results revealed that ewes reared in fluorosis-free areas exhibited significantly lower plasma fluoride and significantly higher haemoglobin levels compared to endemic fluorosis areas (P < 0.0001). However, supplementation with 500 mg*kg-1 BW*day-1 of S. platensis significantly improved these two parameters compared to Group II (P < 0.0001). Ewes in the endemic area also displayed increased oxidative stress (P < 0.05), characterized by decreased ascorbic acid levels and catalase activity, as well as elevated levels of reduced glutathione and malondialdehyde. Supplementation with 500 mg*kg-1 BW*day-1 of S. platensis enhanced the antioxidant status (P < 0.05) by increasing ascorbic acid levels and catalase activity and decreasing levels of reduced glutathione and malondialdehyde. Moreover, this dose yielded similar average daily gains compared to lambs of ewes living in fluorosis-free area. In conclusion, S. platensis may serve as a promising solution for addressing endemic fluorosis in pregnant and lactating ewes.

Clearance of bacteria from lymph nodes in sheep immunized with Brucella suis S2 vaccine is associated with M1 macrophage activation.

Ovine brucellosis is a global zoonotic disease of sheep caused by Brucella melitensis, which inflicts a significant burden on human and animal health. Brucella suis strain S2 (B. suis S2) is a smooth live attenuated vaccine for the prevention of ovine brucellosis in China. However, no previous studies have assessed the immunogenicity of B. suis S2 vaccine after oral immunization in sheep. Here, we attempted to evaluate the ovine immune response over the course of B. suis S2 immunization and to identify in vivo predictors for vaccine development. Body temperature, serum Brucella antibodies, serum cytokines (IL-12p70 and interferon [IFN]-γ), and bacterial load in the mandibular lymph nodes (LN), superficial cervical LN, superficial inguinal LN, and spleen were investigated to determine the safety and efficacy of the vaccine. The abnormal body temperature of sheep occurred within 8 days post-infection (dpi). Brucella suis S2 persisted for a short time (< 21 dpi) in the mandibular LN. The highest level of IL-12p70 was observed at 9 dpi, whereas serum IFN-γ levels peaked at 12 dpi. Transcriptome analysis and quantitative reverse transcription PCR were performed to determine gene expression profiles in the mandibular LN of sheep. Antigen processing and presentation pathway was the dominant pathway related to the dataset. Our studies suggest that the immune response in ovine LN resembled type 1 immunity with the secretion of IL-12p70 and IFN-γ after B.suis S2 immunization and the vaccine may eliminate Brucella via stimulation of M1 macrophages through the course of Th cells.

Evaluation of the effectiveness of foot-and-mouth disease vaccination of animals in the buffer zone of the Republic of Armenia in 2016-2020.

BACKGROUND: Foot-and-mouth disease (FMD) is a high impact viral disease of livestock for which vaccines are extensively used for limiting the spread of infection. Armenia shares a border with both Turkey and Iran where FMD is endemic, making vaccination an important component of Armenia's control strategy. Additionally, Armenian veterinary services utilize both passive and active monitoring for prevention control. METHODS: We sought to determine the immune status of animals vaccinated against FMD and to evaluate the effectiveness of our vaccination policy in Armenia. This was conducted in three regions including Shirak, Armavir, and Ararat Region which are located in the buffer zones that border Turkey and Iran. Through active monitoring in 2020, we studied blood serum samples from cattle and sheep using an enzyme immunoassay to determine the level of immune animals in these regions following the use of a polyvalent inactivated vaccine containing FMDV serotypes A, O, and Asia-1 that are relevant for this region. ELISA titers were assessed at 28, 90, and 180 days after vaccination in cattle of three age groups at the time of initial vaccination: 4-6 months, 6-18 months and ≥ 24 months of age with sheep of all ages. RESULTS: The 3 age groups of cattle had similarly high levels of immunity with over 90% of the cattle showing a ≥ 50% protective titer 28 days after the first vaccination. By day 90, titers in cattle from the initial 4-18-month age groups dropped below 58% across the 3 serotypes and at or below 80% for the oldest cattle ≥ 24 months. Re-vaccination of cattle at 120 days did improve protective titers but never reached the level of immunity of the first vaccination. Sheep showed a similar rapid drop to less than 50% having a ≥ 50% protective titer at 90 days emphasizing the need for continual revaccination. CONCLUSIONS: The results of this study have important implications for the current FMD vaccine policy in Armenia and improves our understanding of the rapid loss of protective titers over short periods. Since small ruminants are only vaccinated once per year and vaccination titers drop rapidly by 90 days suggests that they are vulnerable to FMD and that vaccination protocols need to be updated. Cattle should continue to be vaccinated every 3-6 months depending on their age to maintain a protective level of antibodies to protect them from FMD. More studies are needed to understand the possible role of small ruminants in the epidemiology of FMD and to evaluate revaccination at shorter intervals. These results show the concerns of rapid loss of protection to both cattle and small ruminants following 1 or more doses of commercial vaccines and that additional vaccines need to be evaluated in both groups to know how often they must be vaccinated to provide full protection. The addition of challenge studies should also be considered to better understand the level of protection as measured by serology and how it relates to protection from challenge. These results should be considered by anyone using these vaccines in cattle and sheep at longer than 3 month intervals.

Real-time decision-making during emergency disease outbreaks.

In the event of a new infectious disease outbreak, mathematical and simulation models are commonly used to inform policy by evaluating which control strategies will minimize the impact of the epidemic. In the early stages of such outbreaks, substantial parameter uncertainty may limit the ability of models to provide accurate predictions, and policymakers do not have the luxury of waiting for data to alleviate this state of uncertainty. For policymakers, however, it is the selection of the optimal control intervention in the face of uncertainty, rather than accuracy of model predictions, that is the measure of success that counts. We simulate the process of real-time decision-making by fitting an epidemic model to observed, spatially-explicit, infection data at weekly intervals throughout two historical outbreaks of foot-and-mouth disease, UK in 2001 and Miyazaki, Japan in 2010, and compare forward simulations of the impact of switching to an alternative control intervention at the time point in question. These are compared to policy recommendations generated in hindsight using data from the entire outbreak, thereby comparing the best we could have done at the time with the best we could have done in retrospect. Our results show that the control policy that would have been chosen using all the data is also identified from an early stage in an outbreak using only the available data, despite high variability in projections of epidemic size. Critically, we find that it is an improved understanding of the locations of infected farms, rather than improved estimates of transmission parameters, that drives improved prediction of the relative performance of control interventions. However, the ability to estimate undetected infectious premises is a function of uncertainty in the transmission parameters. Here, we demonstrate the need for both real-time model fitting and generating projections to evaluate alternative control interventions throughout an outbreak. Our results highlight the use of using models at outbreak onset to inform policy and the importance of state-dependent interventions that adapt in response to additional information throughout an outbreak.

Foot-and-mouth disease vaccines: recent updates and future perspectives.

Foot-and-mouth disease (FMD) is a major worldwide viral disease in animals, affecting the national and international trade of livestock and animal products and leading to high economic losses and social consequences. Effective control measures of FMD involve prevention through vaccination with inactivated vaccines. These inactivated vaccines, unfortunately, require short-term protection and cold-chain and high-containment facilities. Major advances and pursuit of hot topics in vaccinology and vectorology are ongoing, involving peptide vaccines, DNA vaccines, live vector vaccines, and novel attenuated vaccines. DIVA capability and marker vaccines are very important in differentiating infected animals from vaccinated animals. This review focuses on updating the research progress of these novel vaccines, summarizing their merits and including ideas for improvement.

Evaluating the efficacy of hydrogen peroxide vapour against foot-and-mouth disease virus within a BSL4 biosafety facility.

An evaluation was made of the efficacy of 35% hydrogen peroxide vapour (HPV) against foot-and-mouth disease virus (FMDV) in a biosafety facility. Biological indicators (BIs) were produced using three serotypes of FMDV, all with a titre of ≥106 TCID50 per ml. Fifteen BIs of each serotype were distributed across five locations, throughout a 30-m3 airlock chamber, producing a total of 45 BIs. Thirty-five percent HPV was generated and applied using a Bioquell vaporization module located in the centre of the chamber. After a dwell period of 40 min, the HPV was removed via the enclosures air handling system and the BIs were collected. The surfaces of the BIs were recovered into Glasgow's modified Eagle's medium (GMEM), cultivated in BHK21 Cl13 cell culture and analysed for evidence of cytopathic effect (CPE). No CPE was detected in any BI sample. Positive controls showed CPE. The experimentation shows that FMDV is susceptible to HPV decontamination and presents a potential alternative to formaldehyde. SIGNIFICANCE AND IMPACT OF THE STUDY: Foot-and-mouth disease virus (FMDV) is an important pathogen in terms of biosafety due to its infectious nature and wide range of host animals, such as cattle, sheep, goats and pigs. Outbreaks of FMDV can have a severe impact on livestock production, causing morbidity, mortality, reduced yields and trade embargoes. Laboratories studying FMDV must possess BSL4 robust bio-decontamination methods to prevent inadvertent release. Formaldehyde has been the primary agent for environmental decontamination, but its designation as a human carcinogen has led to a search for alternatives. This study shows 35% hydrogen peroxide vapour has the potential to be a rapid, effective, residue-free alternative.

Vaccination of cattle only is sufficient to stop FMDV transmission in mixed populations of sheep and cattle.

We quantified the transmission of foot-and-mouth disease virus in mixed cattle-sheep populations and the effect of different vaccination strategies. The (partial) reproduction ratios (R) in groups of non-vaccinated and vaccinated cattle and/or sheep were estimated from (published) transmission experiments. A 4 × 4 next-generation matrix (NGM) was constructed using these estimates. The dominant eigenvalue of the NGM, the R for a mixed population, was determined for populations with different proportions of cattle and sheep and for three different vaccination strategies. The higher the proportion of cattle in a mixed cattle-sheep population, the higher the R for the mixed population. Therefore the impact of vaccination of the cattle is higher. After vaccination of all animals R = 0·1 independent of population composition. In mixed cattle-sheep populations with at least 14% of cattle, vaccination of cattle only is sufficient to reduce R to < 1.

Importance of foot and mouth disease vaccine purity in interpreting serological surveys.

The aim of this study was to determine whether the degree of purity achieved in conventional vaccines against the foot and mouth disease virus in Argentina interferes with the interpretation of seroepidemiological surveys for confirming the absence of viral activity, which are performed to support the recognition of free zones practising vaccination. The evaluation of 168 vaccine series due to be marketed in Argentina (2006-2012) and subjected to official control testing in cattle, as well as repeated vaccination of cattle and other species using vaccines with high antigen concentrations, demonstrated that they did not induce antibodies to non-structural proteins (NSPs). The results show clearly that vaccines with satisfactory potency do not induce a response to NSPs, even by forcing the immune response through more concentrated doses with multiple valences and revaccination protocols at shorter irtervals than in vaccination campaigns. These results confirm that the vaccines used in routine vaccination programmes have a degree of antigen purification consistent with the needs observed on the basis of sampling for serological surveillance. Moreover, serological surveys conducted in 2006-2011 by Argentina's official Veterinary Services--the National Health and Agrifood Quality Service (SENASA)--on more than 23,000 sera per year from cattle included in the vaccination programme, in order to confirm the absence of virus circulation, revealed an average 0.05% of reactive results, consistent with the specificity of the tests. In conclusion, the vaccines produced by conventional methods and with proven potencythat are available in Argentina are sufficiently purified to ensure thatthey do not interfere with the interpretation of sampling for serological surveillance performed to support the recognition of FMD-free zones practising vaccination.

Antibiotic use in the Northern Irish sheep flock: What lessons can be learnt from medicine records and farmer attitudes to improve stewardship of these essential medicines?

Stewardship of antibiotics used in livestock production has come under increasing scrutiny, from both the animal welfare point of view and due to concerns that antibiotic use in livestock may pose a risk to human health through selection pressure to drive development of antibiotic resistant strains of bacteria. Despite this concern, however, antibiotic consumption in the sheep sector is currently poorly described. This study determines the range and quantities of antibiotics used in the Northern Irish (NI) sheep flock as well as exploring drivers for their use. A mixed-methods approach was utilised, with an anonymous online scoping survey, analysis of the medicine records from 52 NI sheep farms and semi-structured interviews undertaken with 27 farmers. Eighteen farmers contributed both records and participated in interviews. Veterinary medicine records were derived from two sources: on-farm medicine books (seven) or veterinary practice sales data (51). As six of these farmers provided information from both sources a total of 52 unique farms participated. Overall, antibiotic use in sheep on the 52 farms sampled was low, with a median value of 11.35 mgPCU-1 (mean 13.63 mgPCU-1, sd 10.7; range 0-45.29 mgPCU-1), with all farms below 50 mgkg-1. Critically important antibiotics accounted for 0.21% of all antibiotics purchased. Lameness was the main driver of antibiotic use identified by this study. Others included a range of prophylactic treatments such as oral antibiotics to prevent watery mouth, injectable antibiotics to prevent abortion and following assisted lambing. Farmers acknowledged some of these uses had become habitual over time. The veterinary medicine sales records demonstrated significant sales of antibiotics not authorised for use in sheep, on an ongoing, rather than case-by-case, basis. Farmers were positive about their veterinarian's ability and knowledge to improve flock welfare and productivity, but were unwilling to pay for this advice. However, veterinarians may have facilitated weak medicine stewardship through a failure to adequately challenge farmers seeking antibiotics. Farmers did not maintain accurate or up-to-date on farm medicine or production records in the majority of cases. Despite this lack of on-farm recording, veterinary sales records can be studied in consultation with farmers to provide veterinarians with a farm-specific insight into antibiotic use and related attitudes and behaviours. Farmers and veterinarians can then identify areas and behaviours to target collaboratively, improving antibiotic and wider medicine stewardship, whilst simultaneously improving flock health and productivity.

Adoption of veterinary vaccines, determining factors, and barriers in Southwest Ethiopia: Implications for livestock health and disease management strategies.

In Ethiopia, the use of veterinary vaccines to control animal diseases is an effective strategy. A study conducted in Southwest Ethiopia from October 2020 to October 2021 aimed to determine the adoption level of veterinary vaccines and factors affecting their use. The study used multistage random sampling to select districts and interviewed 476 farmers who had either adopted or not adopted the vaccines. The study found that certain diseases should be prioritized for vaccination to safeguard the health of cattle, sheep, goats, and poultry. These include anthrax (19.12 %), blackleg (17.65 %), foot and mouth disease (10.50 %), and lumpy skin disease (8.82 %) in cattle, and pasteurellosis (18.07 %), contagious caprine pleuropneumonia (15.97 %), peste des petits ruminants (14.15 %), and Orf (13.45 %) in sheep and goats. Newcastle disease (21.85 %), infectious bursal disease (19.33 %), and coccidiosis (17.02 %) were identified as high-priority diseases for flock health. Overall, 30.7 % of farmers were adopters of veterinary vaccines, while 69.3 % were non-adopters. The study identified several factors that influence the likelihood of adopting veterinary vaccines, including breed type (OR = 9.1, p < 0.0001), production size (OR = 9.7, p < 0.0001), production type (OR = 2.7, p < 0.0001), and farm location (OR = 9.8, p = 0.001). Common barriers to vaccination included a lack of disease knowledge, high vaccine costs, limited vaccine availability, and administration difficulties. Insights from the study can guide strategies for promoting veterinary vaccine adoption in Ethiopia. Stakeholders should pay attention to these findings since vaccine use is crucial for controlling animal diseases, enhancing animal health, and preventing economic losses. Further research is needed to investigate factors affecting enhanced veterinary vaccine adoption.

Assessment of Brazil's vesicular syndrome surveillance system: Profile of notifications and performance of the official veterinary service.

Foot-and-mouth disease (FMD) is an ailment that causes serious damage to the productive chain, and its control through vaccination is of utmost importance for its eradication. Brazil initiated the National Foot-and-Mouth Disease Surveillance Program (PNEFA) with the aim of making the country FMD-free by 2026. As part of the program, notifications of vesicular lesions became mandatory for the Official Veterinary Service (OVS), which is responsible for verifying them. Due to its size, border areas with countries that do not have FMD-free status pose a risk to Brazil and require greater attention. This study described the profile of notifications of suspected outbreaks of vesicular syndrome in Brazil and analyzed the performance of the surveillance system. The results showed 7134 registered notifications of suspected vesicular syndrome outbreaks from 2018 to 2022, with 2022 having the highest number (n = 2343 or 32.85 %). The species that generated the most notifications were swine (90.99 %), cattle and buffaloes (7.54 %), goats and sheep (1.44 %), and others (0.03 %). The sources of notification were "Veterinary medicine professionals" (61.82 %), "Owners or employees" (13.66 %), "Third parties" (8.90 %), "OVS" (7.20 %), and "others" (2.66 %). 41.69 % of notifications originated from non-border municipalities, and 58.32 % from border areas. Only the state of Paraná account for 51.73 % of the total notifications. This state also accounted for 66.70 % of the 32.47 % of notifications with a final diagnosis of "absence of clinically compatible signs or susceptible animals", indicating a certain lack of knowledge in the area, leading to unnecessary notifications and system overload. The performance of the OVS was evaluated based on the service response time from notification registration trough Logistic and Negative binomial regressions. A total of 27.83 % of notifications did not meet the Brazilian legally specified time, and the zone related to the state of Parana needs improvements in performance. The presence and peaks of Senecavirus A cases may have influenced an increased number of swine notifications and led to a decrease in OVS response time. The results demonstrate better performance of surveillance in border areas. Given the vast territory of Brazil, it is not expected that 100 % of responses occur within the legal timeframe, however, the performance of the surveillance system proved to be adequate, with 86 % complied to the legislation. The performance indicators could be used as a monitoring tool, along with indicators to demonstrate system overload. Continued education actions are crucial for strengthening PNEFA.

Induction of immune responses in sheep by vaccination with liposome-entrapped DNA complexes encoding Toxoplasma gondii MIC3 gene.

Toxoplasma gondii is a parasite that has been extensively studied due to its medical and veterinary importance in terminating pregnancies. Consequently, a satisfactory vaccine is required to control its adverse effects on pregnant animals. The microneme protein, MIC3, is a major adhesion protein that binds to the surface of host cells and parasites, and is therefore a potential vaccine against T. gondii. The viability of MIC3 as a vaccine is investigated in this study. Sheep were injected twice, intramuscularly, with plasmids containing DNA encoding for the mature form of MIC3 protein formulated into liposomes. Control sheep were injected with an empty vector or received no injections. The injection of sheep with DNA plasmids encoding for MIC3 elicited an immune response after the first and second injections as indicated by antibody responses and the production of IFN-gamma. The immune response, as measured by the IgG2 and IgG1 serum levels, was boosted after the injection of the MIC3 DNA vaccine together with high anti-MIC3 antibodies. The results demonstrate that the intramuscular injection of sheep with a plasmid containing DNA coding for MIC3 protein induces a significant and effective immune response against T. gondii.

Investigation of honey bee venom effect on the immunogenicity of foot-and-mouth disease vaccine in sheep.

Background: Foot-and-mouth disease (FMD) is one of the most highly contagious and economically significant diseases of cloven-hoofed animals worldwide. FMD virus (FMDV) is the cause of the disease. The virus has seven serological types, identified as; O, A, C, SAT1, SAT2, SAT3, and Asia1. The aim of this study enhancement of FMD vaccine immunogenicity is the unique way to control FMD in Egypt. Aim: Our research studied the effect of bee venom (BV) as simultaneously inoculated with the commercial vaccine on the immune response of experimentally vaccinated sheep in comparison with the inoculation of the vaccine alone through evaluation of the cellular and humoral immune response. Methods: Estimation of cellular immunity using phagocytic activity, phagocytic percentage, lymphocyte blastogenesis, interleukin-6 (IL-6), and interleukin-12 (IL-12) and estimation of humoral immunity using serum neutralization test (SNT) and enzyme-linked immunosorbent assay (ELISA). Result: Evaluation of the cellular immunity expressed in lymphocyte blastogenesis, phagocytic activity, phagocytic percentage, IL-6, and IL-12 showed higher levels in sheep vaccinated by the trivalent FMD vaccine (serotypes O pan Asia, A Iran O5, and SAT2/EGY/2012) with BV comparable to those induced by the vaccine alone. Following up the humoral immune response of vaccinated sheep revealed that FMDV antibodies serotypes O pan Asia, A Iran O5, and SAT2/EGY/2012 as measured by SNT and ELISA assay induced by FMD with BV were higher than those induced by inactivated FMD alone. Conclusion: The inoculation of BV with FMD vaccine simultaneously is of high benefit inducing high level of specific immunity which could be of long duration.

Antibody response of sheep to simultaneous vaccination of foot-and-mouth disease, peste des petits ruminants, sheep pox and goat pox, and bluetongue vaccines.

There are many infectious animal diseases in T urkey and generally, vaccination is the primarly control strategy to combat them. However, it is difficult to apply all vaccines in a definite period in the field due to limitations of the labor and finance. Rapid vaccination and effective use of labor can be possible with the help of simultaneous vaccine administrations. The study aims to show the effects of simultaneous foot-and-mouth disease (FMD), peste des petits ruminants (PPR), sheep pox and goat pox (SGP), and bluetongue (BT) vaccine administration on the antibody response of sheep. For this aim, 30 sheep were divided into one experiment and 5 control groups. Blood samples were collected in each group at 0, 30 and 60 days post-vaccination (DPV). Immune response was measured with virus neutralization test (VNT) and, liquid phase blocking ELISA (LPBE) for FMDV; VNT for BTV and PPR. A live virus challenge study was performed to determine the immune response of SGP vaccine. As a result, antibody titers for each vaccine agent decreased on 60 DPV with the simultaneous vaccination except FMD. The difference between means of antibody titer decrease with single and simultaneous vaccinations is significant especially for BTV and PPR vaccines at 60DPV (p<0.05). Briefly, this decreasing immune response of three live vaccines can be explained with the development of the interference, administration of these vaccines from the same injection site, the effect of cytokines, especially IL-10 effect of SGP vaccine. It was concluded that four vaccines can not be used simultaneously in sheep.

FMD vaccine allocation and surveillance resourcing options for a potential Australian incursion.

Australian Animal Disease Spread (AADIS) epidemiological simulation modelling of potential foot-and-mouth disease outbreaks in the state of Victoria, Australia examined the targeted use of limited vaccine supplies in combination with varying surveillance resources. Updated, detailed estimates of government response costs were prepared based on state level data inputs of required and available resources. Measures of outbreak spread such as duration and numbers of animals removed through depopulation of infected and vaccinated herds from the epidemiological modelling were compared to summed government response costs. This comparison illustrated the trade-offs between targeted control strategies combining vaccination-to-remove and varying surveillance capacities and their corresponding costs. For this intensive cattle and sheep producing region: (1) Targeting vaccination toward intensive production areas or toward specialized cattle operations had outbreak control and response cost advantages similar to vaccination of all species. The median duration was reduced by 27% and response costs by 11%. (2) Adding to the pool of outbreak surveillance resources available further decreased outbreak duration and outbreak response costs. The median duration was reduced by an additional 13% and response costs declined by an additional 8%. (3) Pooling of vaccine resources overcame the very early binding constraints under proportional allocation of vaccines to individual states with similar reductions in outbreak duration to those with additional surveillance resources. However, government costs rose substantially by over 40% and introduced additional risk of a negative consumer response. Increased knowledge of the outbreak situation obtained from more surveillance led to better-informed vaccination deployment decisions in the short timeframe they needed to be made.

A comprehensive review on endemic and experimental fluorosis in sheep: Its diverse effects and prevention.

Fluoride is a natural element widely distributed in the environment and plays an important role in the growth of humans and animals. However, in many species, high concentrations of fluoride induce several problems, such as dental, skeletal, and non-skeletal fluorosis. Sheep living in endemic areas are sensitive to the chronic toxicity of fluoride, and they have been found to suffer not only from teeth and bone problems but also from other organs. Studies indicating the chronic harmful effects of fluoride on teeth, bones, blood biochemical parameters, kidney, liver, heart, reproductive system and growth in sheep have been clearly summarized in this review. Besides, this work also includes updated progress in terms of prevention or reduction of fluoride toxicity in this species.

On-farm evaluation of a predictive model for Australian beef and sheep producers' vulnerability to an outbreak of foot and mouth disease.

To explore Australian sheep and beef producer vulnerability to an emergency animal disease outbreak, Bayesian Network models have been developed, with the ultimate goal of creating risk management tool for outbreak preparedness. These models were developed using multiple stakeholder elicitation including modelling experts, epidemiologists and on-farm stakeholders, including on-farm/survey data. An evaluation of the model's predictive capacity was conducted, using independent, blinded on-farm vulnerability assessments. Nine properties were visited, four each with sheep and beef enterprises, and one mixed enterprise. There were some discrepancies between the model predictions and on-farm assessment in the beef enterprises, with greater disparity with the sheep properties. Discrepancies between the model predictions and on-farm assessments have created opportunities for examination of the data collection process for the model development, the model itself and the on-farm assessment process. Bayesian Network approaches that allow for the inclusion of both continuous and discrete variables may improve the usefulness of these models, avoiding the loss of nuanced data by the need for discretisation of continuous variables, as will the inclusion of input from on-farm stakeholders in model development. Future work includes more data collection to improve the sensitivity of the model predictions, and a deeper, systemic exploration of the factors that may impact Australian producers' vulnerability to an emergency animal disease outbreak.

Destructive tension: mathematics versus experience--the progress and control of the 2001 foot and mouth disease epidemic in Great Britain.

The 2001 foot and mouth disease epidemic in Great Britain was characterised by control using both traditional and novel methods, some resulting from conclusions of mathematical models. Seven days before the implementation of the novel controversial automatic pre-emptive culling of all susceptible livestock on premises adjacent to infected premises (the 'contiguous cull'), the spread of infection had already been controlled by a combination of the traditional stamping out policy with a national movement ban on livestock. A second controversial novel policy requiring the slaughter of sheep within 3 km of premises on which disease had been confirmed (the 3-km cull) also commenced after the peak of infection spread, was untargeted and took several weeks to complete; serosurveillance of culled sheep detected infection in only one flock, suggesting that cryptic infection of sheep was not propagating the epidemic. Extensive post-epidemic serological surveillance of sheep found only a small number of seropositive animals in a very few flocks, suggesting that foot and mouth disease may self-limit in extensive sheep populations. The epidemic was finally brought to an end following the introduction of enhanced agricultural movement restrictions and biosecurity measures. A welfare culling scheme of unaffected animals was required to support the prolonged national livestock movement ban. The models that supported the contiguous culling policy were severely flawed, being based on data from dissimilar epidemics; used inaccurate background population data, and contained highly improbable biological assumptions about the temporal and quantitative parameters of infection and virus emission in infected herds and flocks.

Cattle, sheep and pigs vaccinated against foot and mouth disease: does trade in these animals and their products present a risk of transmitting the disease?

The foot and mouth disease (FMD) status of a country or region has a profound bearing on access to export markets for live animals and animal products. In countries without FMD-free status, and in accordance with the international standards of the World Organisation for Animal Health (OIE), restrictions may be applied to trade in both vaccinated and unvaccinated animals and their products. Available information suggests that, provided there is compliance with essential criteria concerning vaccines, vaccination and other zoosanitary measures (especially quarantine and ante- and post-mortem inspection), the risk of spreading FMD through the importation of vaccinated cattle, sheep and pigs is extremely small. The risk from products derived from vaccinated animals is even smaller, provided that appropriate risk mitigation measures are applied. Knowledge of the zoosanitary status of the exporting country is critical for risk assessment, but can be difficult to verify. Although empirical evidence and practical experience strongly indicate low risk, it is not possible to assert that the risk is zero for vaccinated animals or their products. In the absence of key factual data, risk analysis is only practicable on a qualitative or semi-quantitative basis. However, a very low level of risk is both unavoidable and acceptable if such trade is to be conducted.

Secure Sheep and Wool Supply Plan for Continuity of Business.

Sheep operations will be subject to movement controls during a US foot and mouth disease outbreak and should be prepared to manage animal and product movement disruptions. The voluntary Secure Sheep and Wool Supply (SSWS) Plan for Continuity of Business provides tools for the sheep industry to develop contingency plans, write enhanced, operation-specific biosecurity plans, and learn about disease surveillance opportunities and challenges. The SSWS Plan is science-based and risk-based, funded by the American Sheep Industry Association, and developed collaboratively with industry, government officials, and veterinarians at Iowa State University. For more information, visit www.securesheepwool.org.