Foot-and-mouth Disease Outbreaks Research Articles

Using a participatory qualitative risk assessment to estimate the risk of introduction and spread of transboundary animal diseases in scarce-data environments: A Spatial Qualitative Risk Analysis applied to foot-and-mouth disease in Tunisia 2014-2019.

This article presents a participative and iterative qualitative risk assessment framework that can be used to evaluate the spatial variation of the risk of infectious animal disease introduction and spread on a national scale. The framework was developed through regional training action workshops and field activities. The active involvement of national animal health services enabled the identification, collection and hierarchization of risk factors. Quantitative data were collected in the field, and expert knowledge was integrated to adjust the available data at regional level. Experts categorized and combined the risk factors into ordinal levels of risk per epidemiological unit to ease implementation of risk-based surveillance in the field. The framework was used to perform a qualitative assessment of the risk of introduction and spread of foot-and-mouth disease (FMD) in Tunisia as part of a series of workshops held between 2015 and 2018. The experts in attendance combined risk factors such as epidemiological status, transboundary movements, proximity to the borders and accessibility to assess the risk of FMD outbreaks in Tunisia. Out of the 2,075 Tunisian imadas, 23 were at a very high risk of FMD introduction, mainly at the borders; and 59 were at a very high risk of FMD spread. To validate the model, the results were compared to the FMD outbreaks notified by Tunisia during the 2014 FMD epizootic. Using a spatial Poisson model, a significant alignment between the very high and high-risk categories of spread and the occurrence of FMD outbreaks was shown. The relative risk of FMD occurrence was thus 3.2 higher for imadas in the very high and high spread risk categories than for imadas in the low and negligible spread risk categories. Our results show that the qualitative risk assessment framework can be a useful decision support tool for risk-based disease surveillance and control, in particular in scarce-data environments.

Modeling Intervention Scenarios During Potential Foot-and-Mouth Disease Outbreaks Within U.S. Beef Feedlots.

Foot-and-mouth disease (FMD) is a highly contagious disease of livestock and has severely affected livestock industries during the past two decades in previously FMD-free countries. The disease was eliminated in North America in 1953 but remains a threat for re-introduction. Approximately 44% of the on-feed beef cattle in the U.S. are concentrated in feedlots <32,000 heads, but little information is available on dynamics of FMD in large feedlots. Therefore, there is a need to explore possible management and intervention strategies that might be implemented during potential FMD outbreaks on feedlots. We used a within home-pen stochastic susceptible-latent-infectious-recovered (SLIR) FMD dynamics model nested in a meta-population model of home-pens in a feedlot. The combinatory model was previously developed to simulate foot-and-mouth disease virus (FMDv) transmission within U.S. beef feedlots. We evaluated three intervention strategies initiated on the day of FMD detection: stopping movements of cattle between home-pens and hospital-pen(s) (NH), barrier depopulation combined with NH (NH-BD), and targeted depopulation of at-risk home-pens combined with NH (NH-TD). Depopulation rates investigated ranged from 500 to 4,000 cattle per day. We evaluated the projected effectiveness of interventions by comparing them with the no-intervention FMD dynamics in the feedlot. We modeled a small-size (4,000 cattle), medium-size (12,000 cattle), and large-size (24,000 cattle) feedlots. Implementation of NH delayed the outbreak progression, but it did not prevent infection of the entire feedlot. Implementation of NH-BD resulted in depopulation of 50% of cattle in small- and medium-size feedlots, and 25% in large-size feedlots, but the intervention prevented infection of the entire feedlot in 40% of simulated outbreaks in medium-size feedlots, and in 8% in large-size feedlots. Implementation of NH-TD resulted in depopulation of up to 50% of cattle in small-size feedlots, 75% in medium-size feedlots, and 25% in large-size feedlots, but rarely prevented infection of the entire feedlot. Number of hospital-pens in the feedlot was shown to weakly impact the success of NH-TD. Overall, the results suggest that stopping cattle movements between the home-pens and hospital-pens, without or with barrier or targeted cattle depopulation, would not be highly effective to interrupt FMDv transmission within a feedlot.

PATHOLOGY OF FOOT AND MOUTH DISEASE (FMD) OUTBREAD IN CATTLE, SHEEP AND PIGS IN IBADAN

The death of 18 calves (mostly of exotic breeds) during an outbreak of FMD (SAT-2) was attributed to sever heart lesions consisting of nonsuppurative myo cardial degeneration, haemorrhage and calcification. Mouth and feet lesions were also present. In adult cattle as well as sheep and pigs, mortality was very low and was attributed mainly to some other concurrent or secondary conditions. In view of the unusual susceptibility of exotic cattle (especially calves) it is suggested that extra precautionary measures be taken against FMD when pregnant cows are imported to enzootic areas.

The Epidemiological and Economic Impact of a Potential Foot-and-Mouth Disease Outbreak in Austria.

An outbreak of foot-and mouth disease (FMD) in an FMD-free country such as Austria would likely have serious consequences for the national livestock sector and economy. The objective of this study was to analyse the epidemiological and economic impact of an FMD outbreak in Austria in order to (i) evaluate the effectiveness of different control measures in two Austrian regions with different livestock structure and density, (ii) analyse the associated costs of the control measures and the losses resulting from trade restrictions on livestock and livestock products and (iii) assess the resources that would be required to control the FMD outbreak. The European Foot-and-Mouth Disease Spread Model (EuFMDiS) was used to simulate a potential FMD outbreak. Based on the epidemiological outputs of the model, the economic impact of the outbreak was assessed. The analysis of the simulations showed that the success of control strategies depends largely on the type of control measures, the geographical location, the availability of sufficient resources, and the speed of intervention. The comparison of different control strategies suggested that from an economic point of view the implementation of additional control measures, such as pre-emptive depopulation of susceptible herds, would be efficient if the epidemic started in an area with high livestock density. Depending on the chosen control measures and the affected region, the majority of the total costs would be attributable to export losses (e.g., each day of an FMD epidemic costs Austria € 9–16 million). Our analysis indicated that the currently estimated resources for surveillance, cleaning, and disinfection during an FMD outbreak in Austria would be insufficient, which would lead to an extended epidemic control duration. We have shown that the control of an FMD outbreak can be improved by implementing a contingency strategy adapted to the affected region and by placing particular focus on an optimal resource allocation and rapid detection of the disease in Austria. The model results can assist veterinary authorities in planning resources and implementing cost-effective control measures for future outbreaks of highly contagious viral diseases.

Analysis of Asia-1 foot-and-mouth disease global spread in 1999–2019

In spite of current foot-and-mouth disease (FMD) preventive measures, the disease outbreaks are annually reported in different countries of the world. FMD tends to extensive spread and growing into epidemics. While being a transboundary infection according to the OIE/FAO classification, FMD severely affects the economy and international trade. The paper describes the analysis of the data on global spread of Type Asia-1 virus-induced FMD in 1999–2019. The virus of this type is most often reported in such Asian countries as Afghanistan, Pakistan, China, Nepal, Iran, Myanmar, from where it can spread to FMD free countries. In China, Asia-1 FMD outbreaks were reported from 2001 to 2009. Previously exotic for our country, the virus of this type was first reported in the Primorsky, Khabarovsk, Zabaikalsky Krais and Amur Oblast in 2005–2006. The results of the phylogenetic analysis of the recovered isolates demonstrated that FMD emergence in the Subjects of the Russian Federation was attributed to the virus introduction from the neighboring territories. Possible virus introduction from China resulted in significant economic expenditures on FMD containment and eradication. In view of the close trade and economic relations between the Russian Federation and such Asia-Pacific countries as China, India, Japan and Republic of Korea, one should place greater focus on the risk of FMDV introduction into the Russian Federation from these countries. Of key importance is intensification of the international cooperation with the Asian countries in the area of joint activities aimed at FMD freedom maintenance.

Investigations into Foot and Mouth Disease Outbreak among Small Ruminants in Karnataka State of India

Background: Foot-and-Mouth Disease (FMD) remains a serious threat to the Indian livestock sector due to significant economic loss associated with it. Systematic vaccination of large ruminants over the years has lead to a gradual reduction in the number of disease outbreaks in India. However exposure to FMDV infection in small ruminants has been recorded during the past few years (Rout et al. 2013). Sheep and goat population have not been vaccinated so far against FMD under the FMD-Control program (FMD-CP). The present study highlighted the outbreak of FMD in small ruminants in Karnataka, India.Methods: During the period 2018-19, seven suspected FMD outbreaks among sheep population in Bellary and Tumakuru districts of Karnataka state were investigated. Tongue epithelium (oral swabs) and foot lesions (n=23) from clinically affected sheep and tissues such as heart, lung, liver, spleen, lymph nodes and kidneys from lambs during post mortem (n=67) were collected. All the samples were processed in the laboratory for the detection of FMD virus antigen by employing Serotype differentiating antigen detection ELISA and by multiplex PCR. Heart tissue samples were also collected in buffered formalin for histopathology study and processed by routine paraffin embedding technique and stained with Hematoxylin and Eosin (H and E). Serum samples from the recovered animals were collected and screened by NSP-ELISA and LPB-ELISA to check the antibody status in the affected herd. Result: A total of seven suspected outbreaks of FMD involving 688 small ruminants was investigated. The outbreak of FMD due to FMDV serotype O was confirmed by ELISA and multiplex PCR assays. Clinically, the affected adult sheep showed typical signs of FMD, while mortality in young lambs was observed without apparent signs of disease. Histologically, heart tissues from FMD affected lambs showed myocardial necrosis with marked aggregations of lymphocytes and neutrophils in the myocardium and perivascular spaces. History of FMD outbreaks in cattle and common grazing land for the livestock, as well as sheep within the reach of these villages, may be the major contributing factors for the outbreaks in sheep populations.

Differentiation of Foot and Mouth Disease Virus Serotypes in Animals in High-Risk Zones of Georgia

Foot and Mouth Disease (FMD) is the most important economic threat to the livestock industry. Outbreaks of FMD can have a devastating impact on livestock production and trade, resulting in significant economic losses in the agricultural sector. As a result, vaccination and containment programs have been implemented internationally to minimize the spread of FMDV. The national vaccination program has been implemented in Georgia since 2012, vaccinating Large Ruminants (LR) and Small Ruminants (SR) with trivalent (A, O, Asia1) vaccine twice annually. However, active seromonitoring surveillance still shows a high seroprevalence of the disease, indicating virus circulation. In this study we attempted to estimate the prevalence of different FMDV serotypes in various risk zones within Georgia. A total of 4991 small and large ruminants were tested for the presence of FMDV nonstructural proteins (NSP) in the blood, and the exact serotypes of positive animals were further investigated through structural protein (SP) based assays. The results show that significant percentages (6.6%) of vaccinated animals were affected by FMD, and those positive animals are usually affected by more than one FMDV serotype. As such, our data call upon a stricter vaccination and monitoring program for FMDV in Georgia, especially considering that due to the geographic location of Georgia, the presence of FMD can have significant impact on transit and can be a threat for other countries as well.

Реализация программы контроля за ящуром на территории Алтайского края

The global epizooticsituation in the recent decade is unfavorable regarding foot-and-mouth disease (FMD). FMD cases are reported on the territory of the Russian Federation in the Primorsky, Transbaikal, Khabarovsk, Krasnodar Territories, Amur and Vladimir Regions, Kara-chay-Cherkess Republic, Kabardino-Balkarian Republic, and the Republic of Bashkortostan; FMD cases are report-ed in cattle, pigs and sheep. In the Altai Region, the last FMD outbreak was reported in 1974. Within the framework of the FMD regionalization by the International Epizootic Bureau (IEB), Russia is divided into four zones: IEB-recognized favorable zone without vaccination which in-cludes most regions of Russia (52 regions); two IEB-recognized favorable zones with vaccination; and IEB-unrecognized zone, i.e.contaminated zone. In order to expand the export opportunities for agricultural products, three more zones were established which in the future in 2022 would receive the status of FMD-free with and without vaccination; the Altai Region entered the zone ofobtaining the status without vaccination. As part of measures to ob-tain a safe status without vaccination, the Altai Regional Veterinary Department, in agreement with the interested agencies, developed and approved the integrated FMD control program for the period from 2020 through 2025 that included preventive measures and monitoring studies of biological materials. As part of monitoring studies in 2020, the Federal Center for Animal Health in Vladimir and the ferent animal species for non-structural proteins of FMD virus by ELISA; the results were negative.

Multi-criteria decision analysis to evaluate foot and mouth disease control strategies with the perspectives of Chief Veterinary Officers in the Asia-Oceania region.

The objective of this study was to evaluate the effectiveness of foot and mouth disease (FMD) control strategies using multi-criteria decision analysis (MCDA). The FMD control strategies were evaluated for epidemiological, economic and social-environmental criteria, accounting for the preferences of Chief Veterinary Officers (CVOs) from the Asia-Oceania region, with the preferences quantified using a questionnaire study. Previously reported simulation results of an FMD epidemic were used to measure the epidemiological effectiveness of FMD control strategies. The simulated FMD epidemic results, such as the number of infected farms, the duration of the epidemic and the outbreak area, were compared for a number of FMD control strategies. Based on previous simulation and economic modelling results and incorporating a literature search to quantify the social and environmental outcomes of an FMD outbreak, MCDA analysis was conducted to evaluate control strategies. According to the overall score in the MCDA results, an FMD control strategy which consisted of a 3-km radius of pre-emptive slaughter, 100 days of movement restriction and vaccinating all FMD-susceptible animals (baseline strategy) was the preferred strategy, with the highest overall score of 62.99. In contrast, the same duration of movement restriction and vaccination strategy with a 0.5-km radius of pre-emptive slaughter was least preferred, with the lowest overall score of 37.05. The evaluation of the FMD control strategies presented here using MCDA has provided scientific evidence for selecting an appropriate baseline FMD control strategy, based on the preferences of CVOs.

Estimating the number of farms experienced foot and mouth disease outbreaks using capture-recapture methods

Foot and mouth disease (FMD) is recognized as an endemic disease in Thailand and throughout other countries in Southeast Asia. The underreporting of FMD outbreaks has affected the true status of the disease. This study aimed to determine the number of dairy farms in Chiang Mai that had experienced FMD outbreaks (FMD outbreak farm) during 2015-2016 using capture-recapture (CR) methods. Two independent FMD outbreak data sources including data from the livestock authorities and survey questionnaires were analyzed using Chapman estimator and Chao estimator. Results showed that the estimated number of FMD outbreak farms was 264 (95% CI = 250, 277) and 273 (95% CI = 259, 292) farms based on the Chapman estimator and Chao estimator, respectively. The estimated prevalence of FMD corresponding to the Chapman estimator was lower than the Chao estimator. The active approach of the survey method offered a higher degree of sensitivity compared to the passive method used by the livestock authorities. Estimations from the CR method provided an upper bound for the true number of outbreak farms. This study demonstrated the use of the CR method to estimate the true status of FMD outbreaks. Our proposed approach can potentially be used as a tool to enhance the accuracy and sensitivity of established monitoring and surveillance systems.

High seroprevalence of Foot and Mouth Disease in Laos: Call for nationwide vaccination campaigns and disease surveillance.

Foot and mouth disease (FMD) virus remains enzootic in Lao People's Democratic Republic (Lao PDR) due to insufficient control measures, including low vaccination coverage. We assessed virus epidemiology and evaluated knowledge, attitude and practice of Lao farmers and animal health stakeholders towards FMD to support politics in devising evidence-based control measures. Sera were collected from 972 domestic ruminants in three provinces of Lao PDR: Vientiane Capital, Vientiane and Xiengkhouang provinces. Seroprevalence of antibodies directed against non-structural proteins of FMD virus was assessed using a commercial ELISA. Positive sera were further characterized by detecting antibodies directed against the structural proteins of FMD serotypes O, A and Asia 1. Information about farm management, biosecurity practices, livestock trade, and past FMD outbreaks was obtained. Overall 35% (340/972) of the ruminants had antibodies against FMD virus with a similar seroprevalence in each province. Seroprevalence depended significantly on the ruminant species (p<.001): 61% of buffaloes, but only 41% of cattle and 15% of goats were seropositive. While antibodies against FMD serotype Asia 1 were absent, 87% (297/340) of the seropositive animals had antibodies against FMD serotype O and 32% (110/340) against FMD serotype A. Many seropositive animals (31%) had antibodies against both serotypes O and A. The majority of the farmers could name the symptoms of FMD and the susceptible animal species. Although many had likely observed FMD outbreaks in their herd and were aware of FMD vaccines, only few vaccinated their animals. This study confirms that FMD remains enzootic in at least three provinces of Lao PDR where vaccination coverage is low. It also shows the relevance of nationwide active and passive disease surveillance, as well as of vaccination campaigns using bivalent FMD vaccines and targeting all susceptible animal species.

Risk factors for the incursion, spread and persistence of the foot and mouth disease virus in Eastern Rwanda

BackgroundIdentification of risk factors is crucial in Foot-and-mouth disease (FMD) control especially in endemic countries. In Rwanda, almost all outbreaks of Foot-and-Mouth Disease Virus (FMDV) have started in Eastern Rwanda. Identifying the risk factors in this area will support government control efforts. This study was carried out to identify and map different risk factors for the incursion, spread and persistence of FMDV in Eastern Rwanda. Questionnaires were administered during farm visits to establish risk factors for FMD outbreaks. Descriptive statistical measures were determined and odds ratios were calculated to determine the effects of risk factors on the occurrence of FMD. Quantum Geographic Information System (QGIS) was used to produce thematic maps on the proportion of putative risk factors for FMD per village.ResultsBased on farmers’ perceptions, 85.31% (with p < 0.01) experienced more outbreaks during the major dry season, a finding consistent with other reports in other parts of the world. Univariate analysis revealed that mixed farming (OR = 1.501, p = 0.163, CI = 95%), and natural breeding method (OR = 1.626; p = 0.21, CI = 95%) were associated with the occurrence of FMD indicating that the two risk factors could be responsible for FMD outbreaks in the farms. The occurrence of FMD in the farms was found to be significantly associated with lack of vaccination of calves younger than 12 months in herds (OR = 0.707; p = 0.046, CI = 95%).ConclusionsThis is the first study to describe risk factors for persistence of FMDV in livestock systems in Rwanda. However, further studies are required to understand the role of transboundary animal movements and genotypic profiles of circulating FMDV in farming systems in Rwanda.

Managing Welfare and Antimicrobial-Resistance Issues in Treating Foot-and-Mouth Disease Lesions: A New Therapeutic Approach.

IntroductionFoot-and-mouth disease (FMD) causes negative impacts on global food security, the livestock trade, national economies, and farming-family livelihoods, particularly in resource-poor developing countries with inadequate biosecurity and low levels of vaccination from inadequate veterinary services. As smallholder farmers have limited understanding of disease-risk management, their focus in FMD outbreaks is on accessing clinically effective therapies. However, most are provided inappropriate traditional treatments and/or topical or parenteral antibiotics, often delivered by paraveterinarians inadequately trained in antimicrobial custodianship. This results in negative financial impacts on livelihoods plus risks of food safety and development of antimicrobial resistance. We report the use of a novel pain-relief therapy for FMD.MethodsClinical examinations in an outbreak of suspected FMD in April 2019 in Muang Khay village in Luang Prabang province, Laos confirmed signs and lesions of severe, subacute, ulcerative glossitis and interdigital dermatitis, typical of FMD. All affected buffalo (n=99) and cattle (n=37) presented for treatment in a population of 238 large ruminants, from 15 of 136 households, were administered a topical anesthetic pain-relief product (PRP) wound gel by spray-on (10–30 mL per animal) formulation developed for aversive husbandry procedures (Tri-Solfen, Animal Ethics, Australia).ResultsTreatment with PRP resulted in immediate improvement in demeanor and locomotion, and no adverse events were observed. On follow-up interview, all owners confirmed that their animals were eating within 2 days and lesions had healed within 5 days. Having experienced the positive clinical impacts of PRP on affected animals, these and surrounding farmers were keen to purchase the PRP for future use. The veterinary authorities rapidly registered the PRP for FMD therapy in Laos due to the observed efficacy.DiscussionThese findings suggest a potential paradigm shift from treating FMD with expensive antimicrobials, which risks antimicrobial resistance, to a new, less expensive therapeutic approach that reduces animal suffering and may motivate farmers to report disease to access treatment. Use of the PRP is suggested as an innovation that may improve future FMD management, particularly in developing countries.

Real-Time Standard Analysis of Disease Investigation (SADI)-A Toolbox Approach to Inform Disease Outbreak Response.

An incursion of an important exotic transboundary animal disease requires a prompt and intensive response. The routine analysis of up-to-date data, as near to real time as possible, is essential for the objective assessment of the patterns of disease spread or effectiveness of control measures and the formulation of alternative control strategies. In this paper, we describe the Standard Analysis of Disease Investigation (SADI), a toolbox for informing disease outbreak response, which was developed as part of New Zealand's biosecurity preparedness. SADI was generically designed on a web-based software platform, Integrated Real-time Information System (IRIS). We demonstrated the use of SADI for a hypothetical foot-and-mouth disease (FMD) outbreak scenario in New Zealand. The data standards were set within SADI, accommodating a single relational database that integrated the national livestock population data, outbreak data, and tracing data. We collected a well-researched, standardised set of 16 epidemiologically relevant analyses for informing the FMD outbreak response, including farm response timelines, interactive outbreak/network maps, stratified epidemic curves, estimated dissemination rates, estimated reproduction numbers, and areal attack rates. The analyses were programmed within SADI to automate the process to generate the reports at a regular interval (daily) using the most up-to-date data. Having SADI prepared in advance and the process streamlined for data collection, analysis and reporting would free a wider group of epidemiologists during an actual disease outbreak from solving data inconsistency among response teams, daily “number crunching,” or providing largely retrospective analyses. Instead, the focus could be directed into enhancing data collection strategies, improving data quality, understanding the limitations of the data available, interpreting the set of analyses, and communicating their meaning with response teams, decision makers and public in the context of the epidemic.

A Meta-Population Model of Potential Foot-and-Mouth Disease Transmission, Clinical Manifestation, and Detection Within U.S. Beef Feedlots.

Foot-and-mouth disease (FMD) has not been reported in the U.S. since 1929. Recent outbreaks in previously FMD-free countries raise concerns about potential FMD introductions in the U.S. Mathematical modeling is the only tool for simulating infectious disease outbreaks in non-endemic territories. In the majority of prior studies, FMD virus (FMDv) transmission on-farm was modeled assuming homogenous animal mixing. This assumption is implausible for U.S. beef feedlots which are divided into multiple home-pens without contact between home-pens except fence line with contiguous home-pens and limited mixing in hospital pens. To project FMDv transmission and clinical manifestation in a feedlot, we developed a meta-population stochastic model reflecting the contact structure. Within a home-pen, the dynamics were represented assuming homogenous animal mixing by a modified SLIR (susceptible-latent-infectious-recovered) model with four additional compartments tracing cattle with subclinical or clinical FMD and infectious status. Virus transmission among home-pens occurred via cattle mixing in hospital-pen(s), cowboy pen rider movements between home-pens, airborne, and for contiguous home-pens fence-line and via shared water-troughs. We modeled feedlots with a one-time capacity of 4,000 (small), 12,000 (medium), and 24,000 (large) cattle. Common cattle demographics, feedlot layout, endemic infectious and non-infectious disease occurrence, and production management were reflected. Projected FMD-outbreak duration on a feedlot ranged from 49 to 82 days. Outbreak peak day (with maximum number of FMD clinical cattle) ranged from 24 (small) to 49 (large feedlot). Detection day was 4–12 post-FMD-introduction with projected 28, 9, or 4% of cattle already infected in a small, medium, or large feedlot, respectively. Depletion of susceptible cattle in a feedlot occurred by day 23–51 post-FMD-introduction. Parameter-value sensitivity analyses were performed for model outputs. Detection occurred sooner if there was a higher initial proportion of latent animals in the index home-pen. Shorter outbreaks were associated with a shorter latent period and higher bovine respiratory disease morbidity (impacting the in-hospital-pen cattle mixing occurrence). This first model of potential FMD dynamics on U.S. beef feedlots shows the importance of capturing within-feedlot cattle contact structure for projecting infectious disease dynamics. Our model provides a tool for evaluating FMD outbreak control strategies.

Cattle Manure Trade Network Analysis and the Relevant Spatial Pathways in an Endemic Area of Foot and Mouth Disease in Northern Thailand

Animal movement is one of the most important risk factors for outbreaks of foot and mouth disease (FMD) in cattle. Likewise, FMD can spread to cattle farms via vehicles contaminated with the FMD virus. In Northern Thailand, the movement of manure transport vehicles and the circulation of manure bags among cattle farms are considered as potential risk factors for FMD outbreaks among cattle farms. This study aimed to determine the characteristics and movement patterns of manure tradesman using social network analysis. A structured questionnaire was used to identify sequences of farms routinely visited by each tradesman. A total of 611 participants were interviewed, including 154 beef farmers, 407 dairy farmers, 36 tradesmen, and 14 final purchasers. A static weighted directed one-mode network was constructed, and the network metrics were measured. For the manure tradesman–cattle farmer network, the tradesman possessed the highest value of in- and out-degree centralities (71 and 4), betweenness centralities (114.5), and k-core values (2). These results indicated that the tradesman had a high frequency of farm visits and had a remarkable influence on other persons (nodes) in the network. The movement of vehicles ranged from within local districts, among districts, or even across provinces. Unclean manure plastic bags were circulated among cattle farms. Therefore, both vehicles and the bags may act as a disease fomite. Interestingly, no recording system was implemented for the movement of manure transport vehicles. This study suggested that the relevant authority and stakeholders should be aware of the risk of FMD spreading within this manure trading network. The findings from this study can be used as supporting data that can be used for enhancing FMD control measures, especially for FMD endemic areas.

A randomized controlled field trial assessing foot and mouth disease vaccine effectiveness in Gondar Zuria district, Northwest Ethiopia

Foot and mouth disease (FMD) is a highly transmissible viral disease of cloven-hoofed animals, which is endemic in many developing countries. Vaccination is the main tool for FMD control in resource limited endemic countries like Ethiopia. Vaccine quality, which is often questionable in developing countries, is a critical element for effective disease control. The present study was aimed at evaluating the field effectiveness of a trivalent FMD vaccine (containing serotypes O, A and SAT 2), produced and widely used in Ethiopia, in terms of preventing clinical infection and severe disease. A randomized controlled field trial design was employed in the study in which the attack rate of clinical FMD infection in vaccinated cattle was compared with the attack rate in unvaccinated controls in cattle population of 16 villages in Gondar Zuria district, Northwest Ethiopia. The vaccine was administered as a single dose course in the face of an impending FMD outbreak and the trial groups were monitored for clinical infection until the end of the outbreak. The attack rate of clinical FMD 20 days post vaccination in the vaccinated cattle (34 %) was significantly lower than the attack rate in the unvaccinated controls (49 %) (p < 0.001). However, the effectiveness of the vaccine was only 31 % (95 %CI: 20–40 %). This vaccine effectiveness increased to 52 % ((95 %CI: 33–66 %) 42 days post vaccination. The proportion of severely affected cattle in the vaccinated group (5.7 %) was significantly lower than in the unvaccinated group (9.4 %) (p < 0.001), resulting in 39 % (95 %CI: 18–55 %) vaccine effectiveness against severe disease. Generally, the observed level of vaccine effectiveness was lower than the internationally recommended 75 % plus expected percentage of protection for a standard potency 3PD50/dose FMD vaccine. Moreover, the level of effectiveness was insufficient to provide herd immunity to control the disease at the population level. Nevertheless, given the significant difference in the incidence of clinical disease and severity between vaccinated and unvaccinated cattle, it might still be worth using the current vaccine to reduce production losses associated with the disease provided it is cost effective and affordable for the farmers. Factors that cause low effectiveness of the vaccine need to be identified and addressed for effective control of the disease at population level.

FMD-VS: A virtual sensor to index FMD virus scattering.

Foot-and-mouth disease (FMD) models—analytical models for tracking and analyzing FMD outbreaks—are known as dominant tools for examining the spread of the disease under various conditions and assessing the effectiveness of countermeasures. There has been some remarkable progress in modeling research since the UK epidemic in 2001. Several modeling methods have been introduced, developed, and are still growing. However, in 2010 when a FMD outbreak occurred in the Miyazaki prefecture, a crucial problem reported: Once a regional FMD outbreak occurs, municipal officials in the region must make various day-to-day decisions throughout this period of vulnerability. The deliverables of FMD modeling research in its current state appear insufficient to support the daily judgments required in such cases. FMD model can be an efficient support tool for prevention decisions. It requires being conversant with modeling and its preconditions. Therefore, most municipal officials with no knowledge or experience found full use of the model difficult. Given this limitation, the authors consider methods and systems to support users of FMD models who must make real-time epidemic-related judgments in the infected areas. We propose a virtual sensor, designated “FMD-VS,” to index FMD virus scattering in conditions where there is once a notion of FMD; and (2) shows how we apply the developed FMD-VS technique during an outbreak. In (1), we show our approach to constructing FMD-VS based on the existing FMD model and offer an analysis and evaluation method to assess its performance. We again present the results produced when the technique applied to 2010 infection data from the Miyazaki Prefecture. For (2), we outline the concept of a method that supports the prevention judgment of municipal officials and show how to use FMD-VS.

Sequence Analysis of Egyptian Foot-and-Mouth Disease Virus Field and Vaccine Strains: Intertypic Recombination and Evidence for Accidental Release of Virulent Virus.

In spite of annual mass vaccination programs with polyvalent inactivated vaccines, the incidence and economic impact of foot-and-mouth disease (FMD) in Egypt is high. Viruses of the A, O and SAT 2 serotypes are endemic and repeated incursions of new lineages from other countries lead to an unstable situation that makes the selection of appropriate vaccine antigens very difficult. In this study, whole genome sequencing of a 2016 serotype A isolate from Egypt revealed a recombination event with an African serotype O virus. Based on available vaccine matching data, none of the vaccines currently used in Egypt are expected to sufficiently protect against this virus or other viruses of this lineage (A/AFRICA/G-IV) circulating there since 2012. In addition to the risk of vaccine failure caused by strain mismatch, the production of inactivated FMD vaccines is dangerous if adequate biosafety cannot be maintained. Using a high-throughput sequencing protocol optimized for short nucleic acid fragments, the composition of a local inactivated vaccine was analyzed in depth. The serotype O strain identified in the vaccine was genetically identical to viruses found in recent FMD outbreaks in Egypt.

Quantifying the Transmission of Foot-and-Mouth Disease Virus in Cattle via a Contaminated Environment.

Indirect transmission via a contaminated environment can occur for a number of pathogens, even those typically thought of as being directly transmitted, such as influenza virus, norovirus, bovine tuberculosis, or foot-and-mouth disease virus (FMDV). Indirect transmission facilitates spread from multiple sources beyond the infectious host, complicating the epidemiology and control of these diseases. This study carried out a series of transmission experiments to determine the dose-response relationship between environmental contamination and transmission of FMDV in cattle from measurements of viral shedding and rates of environmental contamination and survival. Seven out of ten indirect exposures resulted in successful transmission. The basic reproduction number for environmental transmission of FMDV in this experimental setting was estimated at 1.65, indicating that environmental transmission alone could sustain an outbreak. Importantly, detection of virus in the environment prior to the appearance of clinical signs in infected cattle and successful transmission from these environments highlights there is a risk of environmental transmission even before foot-and-mouth disease (FMD) is clinically apparent in cattle. Estimated viral decay rates suggest that FMDV remained viable in this environment for up to 14 days, emphasizing the requirement for stringent biosecurity procedures following outbreaks of FMD and the design of control measures that reflect the biology of a pathogen.IMPORTANCE Effective control of a disease relies on comprehensive understanding of how transmission occurs, in order to design and apply effective control measures. Foot-and-mouth disease virus (FMDV) is primarily spread by direct contact between infected and naive individuals, although the high levels of virus shed by infected animals mean that virus can also be spread through contact with contaminated environments. Using a series of transmission experiments, we demonstrate that environmental transmission alone would be sufficient to sustain an outbreak. Key observations include that a risk of transmission exists before clinical signs of foot-and-mouth disease (FMD) are apparent in cattle and that survival of virus in the environment extends the transmission risk period. This study highlights the role a contaminated environment can play in the transmission of FMDV and presents approaches that can also be applied to study the transmission of other pathogens that are able to survive in the environment.