Risk assessment as a tool for improving external biosecurity at farm level

Prioritization of pig farm biosecurity for control of Salmonella and hepatitis E virus infections: results of a European expert opinion elicitation

BACKGROUND

In the literature, there is absent or weak evidence on the effectiveness of biosecurity measures to the control of Salmonella spp. and hepatitis E virus (HEV) on pig farms. Therefore, the present study aimed to collect, weigh, and compare opinions from experts on the relevance of several biosecurity measures. An online questionnaire was submitted to selected experts, from multiple European countries, knowledgeable on either HEV or Salmonella spp., in either indoor or outdoor pig farming systems (settings). The experts ranked the relevance of eight biosecurity categories with regards to effectiveness in reducing the two pathogens separately, by assigning a score from a total of 80, and within each biosecurity category they scored the relevance of specific biosecurity measures (scale 1-5). Agreement among experts was analysed across pathogens and across settings.

RESULTS

After filtering for completeness and expertise, 46 responses were analysed, with 52% of the experts identified as researchers/scientists, whereas the remaining 48% consisted of non-researchers, veterinary practitioners and advisors, governmental staff, and consultant/industrial experts. The experts self-declared their level of knowledge but neither Multidimensional Scaling nor k-means cluster analyses produced evidence of an association between expertise and the biosecurity answers, and so all experts' responses were analysed together without weighting or adaptation. Overall, the top-ranked biosecurity categories were pig mixing; cleaning and disinfection; feed, water and bedding; and purchase of pigs or semen, while the lowest ranked categories were transport, equipment, animals (other than pigs and including wildlife) and humans. Cleaning and disinfection was ranked highest for both pathogens in the indoor setting, whereas pig mixing was highest for outdoor settings. Several (94/222, 42.3%) measures across all four settings were considered highly relevant. Measures with high disagreement between the respondents were uncommon (21/222, 9.6%), but more frequent for HEV compared to Salmonella spp.

CONCLUSIONS

The implementation of measures from multiple biosecurity categories was considered important to control Salmonella spp. and HEV on farms, and pig mixing activities, as well as cleaning and disinfection practices, were perceived as consistently more important than others. Similarities and differences in the prioritised biosecurity measures were identified between indoor and outdoor systems and pathogens. The study identified the need for further research especially for control of HEV and for biosecurity in outdoor farming.

What is a biosecurity measure? A definition proposal for animal production and linked processing operations

While biosecurity, a central component of the One Health concept, is clearly defined, a harmonized definition of the term ´biosecurity measure´ (BSM) is missing. In turn, particularly at the farm and policy level, this leads to misunderstandings, low acceptance, poor implementation, and thus suboptimal biosecurity along the food animal production chain. Moreover, different views on BSMs affects making comparisons both at the policy level as well as in the scientific community. Therefore, as part of the One Health EJP BIOPIGEE project, a work group i) collected and discussed relevant inclusion and exclusion criteria for measures to be considered in the context of biosecurity and ii) conducted a systematic literature review for potentially existing definitions for the term BSM. This exercise confirmed the lack of a definition of BSM, underlining the importance of the topic. In the pool of articles considered relevant to defining the term BSM, specific research themes were identified. Based on these outcomes, we propose a definition of the term BSM:

“A biosecurity measure (BSM) – is the implementation of a segregation, hygiene, or management procedure (excluding medically effective feed additives and preventive/curative treatment of animals) that specifically aims at reducing the probability of the introduction, establishment, survival, or spread of any potential pathogen to, within, or from a farm, operation or geographical area.”

The definition provides a basis for policymakers to identify factual BSMs, highlights the point of implementation and supports to achieve the necessary quality standards of biosecurity in food animal production. It also enables clear, harmonized, cross-sectoral communication of best biosecurity practices to and from relevant stakeholders and thus contribute to improving biosecurity and thereby strengthen the One Health approach.

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We propose a harmonized definition for the term “biosecurity measure”.

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Policy makers can use this definition to identify factual BSMs.

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The definition promotes communication of biosecurity practices between stakeholders.

Sleeping with the enemy: Maintaining ASF-free farms in affected areas

African Swine Fever (ASF) continues to spread worldwide, with very limited eradication success in countries where the disease affects domestic pig populations. Various biosecurity tools exist to reduce the on-farm risk incursion of ASF and other diseases. However, their focus on overall biosecurity scores and benchmarking results in recommendations that are not always cost-effective. We propose to apply a risk analysis approach that actively involves farmers and farmworkers in identifying their weakest links in biosecurity and corresponding mitigation efforts. Furthermore, the approach's focus on describing and understanding pathways of introduction and/or spread specific to individual farms creates buy-in from producers for investing in biosecurity measures and improving compliance.

New Approaches for risk assessment and management of bovine protothecosis

Protothecosis is a potential zoonosis related to bovine mastitis. In several countries, a higher incidence of protothecal bovine mastitis that is being recorded and the resistance of Prototheca species to various factors (chlorine, high temperatures, antimicrobial and antiseptic treatments, pH variations), make it difficult to control its spread among farms. The authors aim to describe the infection caused by microalgae, focusing on the problems within cattle farms and proposing new approaches to farm management, based on Regulation (EU) No 2016/429 on transmissible animal diseases. This new flexible approach, based on risk analysis, is a further tool in protecting against Prototheca species. The list of transmissible animal diseases under Regulation (EU) No 2016/429 includes those caused by microorganisms resistant to antimicrobials, which can have important implications for human and animal health, feed and food safety. This approach would involve a series of changes to the rules used for Official Controls (Regulation (EU) No 2017/625) moving from the concept of the food chain to that of the agri-food chain.

Determination of risk factors in cattle and small ruminant livestock enterprises from the perspective of animal life insurance: a case study in Turkey

ABSTRACT The objective of this study was to determine the risk factors in the production processes of cattle and small ruminant breeding enterprises, along with developing a scale that could be used during the insured breeding process in different regions of Turkey. In this study, we obtained information from 252 enterprises from different provinces (Afyonkarahisar, Aksaray, Ankara, Burdur, Karaman, and Konya) of Turkey. Reliability and validity analyses were conducted using the “Risk Assessment Form in Cattle and Small Ruminant Animal Production”. The Cronbach alpha (α) coefficient was used to analyze reliability, while the exploratory factor analysis was applied to analyze the validity. About 68.7% (173) of the enterprises included cattle breeding, while the remaining 31.3% (79) involved small ruminant breeding. To determine the risk factors, twenty-four questions were directed toward the livestock enterprises, and the following six factors were determined: Economic-Political Risks, Yield/Product Losses, Enterprise Technical Risks, Credit/Financing, Workforce, Enterprise Follow-up, and Registration. In the politico-economic risk scoring, the score of enterprises already having Animal life insurance (ALI) was observed to be higher than those who did not have it, with the difference being statistically significant (p<0.05). We interpreted that producers with higher politico-economic risk factor scores preferred insurance. Although the producers could determine the risk factors well, not all producers were necessarily aware of risk measures. Thus, it was necessary to improve the farmers’ perception of risks and support their efforts to manage and reduce these risks. Also, the importance of insurance practices within and out of the farm is predicted to increase gradually to develop more conscious, sustainable, and profitable breeding in agriculture and animal product markets, which are becoming more liberalized day by day.

Reducing the Risk of Transmission of Critical Antimicrobial Resistance Determinants From Contaminated Pork Products to Humans in South-East Asia

Antimicrobial resistance (AMR) is a critical challenge worldwide as it impacts public health, especially via contamination in the food chain and in healthcare-associated infections. In relation to farming, the systems used, waste management on farms, and the production line process are all determinants reflecting the risk of AMR emergence and rate of contamination of foodstuffs. This review focuses on South East Asia (SEA), which contains diverse regions covering 11 countries, each having different levels of development, customs, laws, and regulations. Routinely, here as elsewhere antimicrobials are still used for three indications: therapy, prevention, and growth promotion, and these are the fundamental drivers of AMR development and persistence. The accuracy of detection of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARG) depends on the laboratory standards applicable in the various institutes and countries, and this affects the consistency of regional data. Enterobacteriaceae such as Escherichia coli and Klebsiella pneumoniae are the standard proxy species used for indicating AMR-associated nosocomial infections and healthcare-associated infections. Pig feces and wastewater have been suspected as one of the hotspots for spread and circulation of ARB and ARG. As part of AMR surveillance in a One Health approach, clonal typing is used to identify bacterial clonal transmission from the production process to consumers and patients - although to date there have been few published definitive studies about this in SEA. Various alternatives to antibiotics are available to reduce antibiotic use on farms. Certain of these alternatives together with improved disease prevention methods are essential tools to reduce antimicrobial usage in swine farms and to support global policy. This review highlights evidence for potential transfer of resistant bacteria from food animals to humans, and awareness and understanding of AMR through a description of the occurrence of AMR in pig farm food chains under SEA management systems. The latter includes a description of standard pig farming practices, detection of AMR and clonal analysis of bacteria, and AMR in the food chain and associated environments. Finally, the possibility of using alternatives to antibiotics and improving policies for future strategies in combating AMR in a SEA context are outlined.

Biosecurity in pig farms: a review

The perception of the importance of animal health and its relationship with biosecurity has increased in recent years with the emergence and re-emergence of several diseases difficult to control. This is particularly evident in the case of pig farming as shown by the recent episodes of African swine fever or porcine epidemic diarrhoea. Moreover, a better biosecurity may help to improve productivity and may contribute to reducing the use of antibiotics. Biosecurity can be defined as the application of measures aimed to reduce the probability of the introduction (external biosecurity) and further spread of pathogens within the farm (internal biosecurity). Thus, the key idea is to avoid transmission, either between farms or within the farm. This implies knowledge of the epidemiology of the diseases to be avoided that is not always available, but since ways of transmission of pathogens are limited to a few, it is possible to implement effective actions even with some gaps in our knowledge on a given disease. For the effective design of a biosecurity program, veterinarians must know how diseases are transmitted, the risks and their importance, which mitigation measures are thought to be more effective and how to evaluate the biosecurity and its improvements. This review provides a source of information on external and internal biosecurity measures that reduce risks in swine production and the relationship between these measures and the epidemiology of the main diseases, as well as a description of some systems available for risk analysis and the assessment of biosecurity. Also, it reviews the factors affecting the successful application of a biosecurity plan in a pig farm.

Estimating the level of disease risk and biosecurity on commercial poultry farms in New Zealand

Aims: To collect baseline data on the contact risk pathways and biosecurity practices of commercial poultry farms in New Zealand, investigate the relationship between the farm-level disease contact risks and biosecurity practices, and identify important poultry health concerns of producers. Methods: A cross-sectional survey of all registered New Zealand commercial poultry operations was conducted in 2016 collecting information on farm demographics, biosecurity practices, and contact risk pathways. Survey responses were used to generate an unweighted subjective disease risk score based on eight risk criteria and a subjective biosecurity score based on the frequency with which producers reported implementing seven biosecurity measures. Producer opinions towards poultry health issues were also determined. Results: Responses to the survey response were obtained from 120/414 (29.0%) producers, including 57/157 (36.3%) broiler, 33/169 (19.5%) layer, 24/55 (44%) breeder, and 6/32 (19%) other poultry production types. Median disease risk scores differed between production types (p < 0.001) and were lowest for breeder enterprises. The greatest risk for layer and broiler enterprises was from the potential movement of employees between sheds, and for breeder enterprises was the on- and off-farm movement of goods and services. Median biosecurity scores also differed between production types (p < 0.001), and were highest for breeder and broiler enterprises. Across all sectors there was no statistical correlation between biosecurity scores and disease risk scores. Producers showed a high level of concern over effectively managing biosecurity measures. Conclusions: The uptake of biosecurity measures in the commercial poultry farms surveyed was highly variable, with some having very low scores despite significant potential disease contact risks. This may be related to the low prevalence or absence of many important infectious poultry diseases in New Zealand leading farmers to believe there is a limited need to maintain good biosecurity as well as farmer uncertainty around the efficacy of different biosecurity measures. Further research is needed to understand barriers towards biosecurity adoption including evaluating the cost-effectiveness of biosecurity interventions.

Development of a quantitative risk assessment of bovine viral diarrhea virus and bovine herpesvirus-1 introduction in dairy cattle herds to improve biosecurity

A quantitative risk assessment model was developed to estimate the annual probability of introducing bovine viral diarrhea virus (BVDV) and bovine herpesvirus 1 (BoHV-1) at the farm level through animal movements. Data from 2017 official animal movements, biosecurity questionnaires, scientific literature, and expert opinion from field veterinarians were taken into consideration for model input parameters. Purchasing or introducing cattle, rearing replacement heifers offsite, showing cattle at competitions, sharing transport vehicles with other herds, and transporting cattle in vehicles that have not been cleaned and disinfected were considered in the model. The annual probability of introducing BVDV or BoHV-1 through infected animals was very heterogeneous between farms. The median likelihoods of BVDV and BoHV-1introduction were 12 and 9%, respectively. Farms that purchased cattle from within their region (i.e., local movements) and shared transport with other farms had a higher probability for BVDV and BoHV-1 introduction. This model can be a useful tool to support decision-making on biosecurity measures that should be prioritized to reduce the probability of introduction of these 2 diseases in dairy herds.

Development and validation of a scoring system to assess the relative vulnerability of swine breeding herds to the introduction of PRRS virus

Biosecurity is defined as the set of practices carried out to prevent the introduction and spread of infectious agents in a herd. These practices are essential in swine production, especially for highly infectious agents such as porcine reproductive and respiratory syndrome virus (PRRSv). Even with years of research and experience over the last three decades, PRRSv is still causing productivity losses and is the major health problem affecting the global swine industry. Despite knowledge of the various ways in which the virus can be transmitted from one herd to another (e.g. animals, semen, truck, air, and people), determining the most frequent ways in which the virus is transmitted in the field is difficult. A systematic approach to assess vulnerabilities at a herd level related to PRRSv transmission could help producers prioritize biosecurity practices to reduce or avoid the occurrence of outbreaks. The aim of this study was to develop a biosecurity vulnerability score that represents the relative vulnerability of swine breeding herds to the introduction of PRRSv. To create the biosecurity vulnerability score (outcome), a multi-criteria decision analysis methodology was used to rank and quantify biosecurity practices based on expert opinion. To validate the biosecurity vulnerability score, a survey of biosecurity practices and PRRS outbreak histories in 125 breed-to-wean herds in the U.S. swine industry was used. Data on the frequency of PRRS outbreaks was used to test the hypothesis that biosecurity vulnerability scores were different between farms that have a low incidence of PRRS outbreaks, compared to farms that have a high incidence. In the two databases used, the scores consistently showed that farms with higher scores have a higher frequency of PRRS outbreaks. In the first validation, farms that had never had an outbreak investigation before had a significant (p < 0.02) lower score (0.29; 0.21-0.37) when compared to farms that had 2 or more outbreaks (0.43; 0.39-0.46). In the second, the farms of the control group also had significant (p < 0.004) lower scores (0.30; 0.27-0.33) compared to the case group (0.35; 0.33-0.38). Also, the results suggest that events related to swine movements, transmission by air and water, and people movements should be prioritized. The biosecurity vulnerability scores may be useful to assess vulnerabilities on biosecurity protocols in order to reduce the frequency of PRRS outbreaks and may help producers and veterinarians prioritize investments in improving biosecurity practices over time.

Biosecurity practices on foie gras duck farms, Southwest France

On-farm biosecurity can be assessed by analyzing patterns of practices to better tailor technical advice to producers. Given their close contact with environmental and wildlife disease reservoirs, free-range duck farms are exposed to multiple risk factors of pathogen exposure that are rare or absent in indoor production. The recurrent emergence of Highly Pathogenic Avian Influenza (HPAI) viruses in Southeast Asia and Europe has emphasized the importance of farm-level biosecurity on free-range duck farms. This study was conducted on 46 French duck farms. The farms were visited and an 80-question survey was administered to assess biosecurity practices. Patterns of practices were explored with multiple correspondence analysis and hierarchical cluster analysis. Farms were assigned to one of three clusters in which specific farm types were overrepresented: farms specialized in rearing to grow-out phases and open-circuit full cycle (i.e., all production phases on the farm) farms in cluster 1, closed-circuit full cycle farms in cluster 2, and farms specialized in gavage in cluster 3. Differences in practices might be linked with differences in production constraints. This study provides a baseline assessment of biosecurity practices on foie gras duck farms in Southwest France and will help efforts to adapt biosecurity programs to farm types.

Theoretical value of pre-trade testing for Salmonella in Swedish cattle herds

The Swedish Salmonella control programme includes mandatory action if Salmonella is detected in a herd. The aim of this study was to assess the relative value of different strategies for pre-movement testing of cattle. Three fictitious herds were included: dairy, beef and specialised calf-fattening. The yearly risks of introducing Salmonella with and without individual serological or bulk milk testing were assessed as well as the effects of sourcing animals from low-prevalence areas or reducing the number of source herds. The initial risk was highest for the calf-fattening herd and lowest for the beef herd. For the beef and dairy herds, the yearly risk of Salmonella introduction was reduced by about 75% with individual testing. Sourcing animals from low-prevalence areas reduced the risk by >99%. For the calf-fattening herd, the yearly risk was reduced by almost 50% by individual testing or sourcing animals from a maximum of five herds. The method was useful for illustrating effects of risk mitigation when introducing animals into a herd. Sourcing animals from low-risk areas (or herds) is more effective than single testing of individual animals or bulk milk. A comprehensive approach to reduce the risk of introducing Salmonella from source herds is justified.

Risk Factors for Antimicrobial Resistance in Escherichia coli in Pigs Receiving Oral Antimicrobial Treatment: A Systematic Review

The aim of this literature review was to identify risk factors in addition to antimicrobial treatment for antimicrobial resistance (AMR) occurrence in commensal Escherichia coli in pigs. A variety of studies were searched in 2014 and 2015. Studies identified as potentially relevant were assessed against eligibility criteria such as observation or experiment (no review), presentation of risk factors in addition to (single dosage) antimicrobial use, risk factors for but not resulting from AMR, and the same antimicrobial used and tested. Thirteen articles (nine on observational, four on experimental studies) were finally selected as relevant. It was reported that space allowance, production size/stage, cleanliness, entry of animals and humans into herds, dosage/frequency/route of administration, time span between treatment and sampling date, herd size, distance to another farm, coldness, and season had an impact on AMR occurrence. Associations were shown by one to four studies per factor and differed in magnitude, direction, and level of significance. The risk of bias was unclear in nearly half of the information of observational studies and in most of the information from experimental studies. Further research on the effects of specific management practices is needed to develop well-founded management advice.

Evaluation of the relationship between the biosecurity status, production parameters, herd characteristics and antimicrobial usage in farrow-to-finish pig production in four EU countries

BACKGROUND

High antimicrobial usage and the threat of antimicrobial resistance highlighted the need for reduced antimicrobial usage in pig production. Prevention of disease however, is necessary to obtain a reduced need for antimicrobial treatment. This study aimed at assessing possible associations between the biosecurity level, antimicrobial usage and farm and production characteristics in order to advice on best practices for a low antimicrobial usage and maximum animal health and production. A cross-sectional study was conducted in 227 farrow-to-finish pig herds in Belgium, France, Germany and Sweden between December 2012 and December 2013. Associations between biosecurity status, antimicrobial usage, and production parameters were evaluated with multivariable general linear models, according to an assumed causal pathway.

RESULTS

The results showed that higher antimicrobial usage in sows tended to be associated with higher antimicrobial usage from birth until slaughter (p = 0.06). The antimicrobial usage from birth until slaughter was positively associated with the number of pathogens vaccinated against (p < 0.01). A shorter farrowing rhythm (p < 0.01) and a younger weaning age (p = 0.06) tended to be also associated with a higher antimicrobial usage from birth until slaughter whereas a better external biosecurity (p < 0.01) was related with a lower antimicrobial usage from birth until slaughter.

CONCLUSION

Management practices such as weaning age and biosecurity measures may be important factors indirectly impacting on antimicrobial usage. We therefore promote a holistic approach when assessing the potential to reduce the need for antimicrobial treatments.