Pig Holdings Research Articles

Working with small‐scale pig keepers. Part 2: encouraging antibiotic stewardship

Background: With much effort from both vets and producers, antibiotic use in the pig sector has been reduced by 74 per cent since 2015, as reported by the Veterinary Medicines Directorate (2023). That being said, there is still room for improvement and efforts must now be aligned to tackling areas of inappropriate antibiotic use rather than simply reductions in use. Previous research has identified significant differences in antibiotic use across different systems and so strategies to decrease use or improve antibitoic stewardship in the commercial sector may not be suitable for keepers of small numbers of pigs; contributing factors to inappropriate use across all systems must be understood and addressed.Aim of the article: In this article, the second in a two‐part series on working with small‐scale pig keepers, we discuss steps that supervising vets may take to encourage antibiotic stewardship on small‐scale pig holdings, from pet pigs to small‐scale producers. Part one of this series, published in last month's In Practice, provided advice and information regarding UK pig‐specific legislation.

Working with small‐scale pig keepers. Part 1: encouraging legislative adherence

Background: Threats such as African swine fever (ASF) are in close proximity to the UK; therefore, it is a crucial time to protect the British pig herd from exotic notifiable disease, which can be best achieved through legislative adherence. This is especially the case for laws around the feeding of pigs, which remains the likely route for ASF to enter the UK. Keepers of pigs on a small scale, including keepers of pet pigs, may show variable adherence to the relevant legislation. Furthermore, general farm practitioners, often responsible for supervising small‐scale pig holdings, may be less familiar with legislative requirements than those vets who deal solely with pigs. Despite this, legal requirements must be met on all holdings and overseeing vets are key to encouraging legislative compliance among keepers.Aim of the article: This article, the first in a two‐part series on working with small‐scale pig keepers, serves as a reference for vets so that they can provide their clients with up‐to‐date advice on how to keep pigs within the legal framework for the UK. It also offers advice on how this information could be shared among pig keepers. Part two, which will be published in a subsequent issue of In Practice, will focus on how we, as vets, can encourage antibiotic stewardship on smallholdings.

Provision of veterinary services in livestock holdings in the Russian Federation

Being the primary link in the disease notification system, specialists of the veterinary service in livestock holdings ensure continuous monitoring and control of animal health. This analysis includes assessment of the actual availability of veterinary services in the absolute majority of animal holdings in 85 Subjects of the Russian Federation. In total, the study covered 6,226,368 holdings for major livestock species, such as cattle and small ruminants, pigs, poultry, horses and fur animals. Small-scale holdings have been shown to account for the largest proportion (99.7%) of the total number of livestock farms, while the proportion of holdings where animal health control is daily organized has varied from 0.03% in fur farms to 3% in poultry farms. The significant role of animal owners in small-scale holdings within the implementation of epizootological surveillance has been determined. It was revealed that the main populations of pigs, poultry and fur animals are concentrated in large-scale livestock farms. The study results indicate a relatively favorable situation in pig and poultry holdings, where only single cases of lack of veterinary service were reported. On the contrary there are multiple cases of lack of veterinary care in the farms for rearing cattle, small ruminants, fur animals. The paper highlights the mechanisms for the implementation of tasks assigned to the state veterinary service in terms of the organization of planned preventive and diagnostic veterinary measures in large pig breeding establishments. Proposals were made to introduce a legally fixed obligation for animal owners in large-scale livestock holdings to establish and maintain the production veterinary service, as well as a proposal to establish divisions of the state veterinary service in large-scale livestock establishments.

Eradication of PRRS from Hungarian Pig Herds between 2014 and 2022.

Porcine reproductive and respiratory syndrome (PRRS) is a widespread infectious disease that is currently a major cause of economic losses in pig production. In Hungary, a National PRRS Eradication Program has been introduced to attain a more efficient, economic, and competitive international market position. The program has been also approved by the EU, but the resulting legal obligations have imposed a burden on Hungarian producers to comply with EU competition rules. The implementation of the program has been carried out by the veterinary authorities with the consent of, continuous support from and monitoring conducted by organisations within the pig sector as well as a scientific committee. The PRRS eradication program in Hungary was based on a regional territorial principle and was compulsory for all pig holdings within the regions. In Hungary, large fattening farms operate as all-in/all-out or continuous flow systems. Large-scale breeding herds are predominantly farrow-to-finish types. Although its significance has decreased in recent decades, 20% of the Hungarian pig population is still kept on small (backyard) farms (<100 animals). All PRRSV-infected large-scale farms had to develop a unit-adapted eradication plan, including external and internal biosecurity measures, vaccinations, etc. It was crucial to render each fattening unit free of the disease, as fattening units play a significant role in spreading the virus within the country. The eradication efforts mainly implemented were depopulation-repopulation methods, but on some farms a testing and removal method has been used. As the eradication progressed over the years, the introduction of infected fattening pigs was restricted. Thanks to these measures, Hungarian large-scale fattening farms became PRRSV-free by the end of 2018. The PRRSV-free status of small-scale herds was achieved by the end of 2015 and was maintained between 2016 and 2021. By 31 December 2021, all breeding pigs in large-scale farms in Hungary were free of wild-type PRRS virus. By 31 March 2022, the total pig population of the country, including all backyard farms and fattening units, achieved PRRSV-free status. The future goal is to ensure and maintain the PRRSV-free status of Hungary via strict import regulations of live animals combined with the continuous and thorough screening of incoming and resident herds for the presence of the virus.

Transmission Dynamics of Imported Vaccine-Origin PRRSV-2 within and between Commercial Swine Integrations in Hungary.

This study reports on the molecular epidemiology of Ingelvac-PRRS-MLV-associated cases in Hungary for the period 2020-2021. Field epidemiology investigations led the experts to conclude that imported pigs, which were shipped through transit stations in Denmark, introduced the vaccine virus. The movement of fatteners and the neglect of disease control measures contributed to the spread of the virus to PRRS-free pig holdings in the vicinity. Deep sequencing was performed to genetically characterize the genes coding for the virion antigens (i.e., ORF2 through ORF7). The study isolates exhibited a range of 0.1 to 1.8% nucleotide sequence divergence from the Ingelvac PRRS MLV and identified numerous polymorphic sites (up to 57 sites) along the amplified 3.2 kilo base pair genomic region. Our findings confirm that some PRRSV-2 vaccine strains can accumulate very high number of point mutations within a short period in immunologically naive pig herds.

Semi-Quantitative Risk Assessment of African Swine Fever Virus Introduction in Outdoor Pig Farms.

In a previous study, a semi-quantitative risk assessment was developed to rank pig holdings in terms of likelihood of introducing African swine fever virus (ASFV) by assessing their compliance with biosecurity and exposure to geographical risk factors. The method was initially developed for confined pig holdings, but given that ASF is endemic in wild boar of several countries, we modified the approach to make it suitable for free-range farms as well. In the current study, a total of 41 outdoor pig farms were assessed in an area where exposure to wild boar was generally high (density from 2.3 to 10.3 wild boar per Km2). As expected, non-compliance with biosecurity measures was frequent in outdoor farms, and the frequency of non-compliance indicated that the absence of adequate separation of pigs from the external environment was the major weakness in the farms assessed. In 46.3% of them, there was no fence or, if present, it was not adequate to avoid contact with wild boar. However, the approach adopted proved to be suitable for identifying intervention priorities to mitigate the risk of ASFV spread in free-range pig herds and for identifying the weaknesses of individual farms, as recommended by EFSA in 2021, which suggests implementing tools to improve biosecurity by favoring higher-risk farms.

Spatiotemporal Drivers of the African Swine Fever Epidemic in Lao PDR

African swine fever (ASF) is a devastating transboundary disease of swine. Following the first report of ASF in China in August 2018, ASF spread through South-East Asian nations in 2019. Without control and containment measures, ASF can decimate smallholder pig holdings and disrupt value chains. This study aimed to describe the spatiotemporal spread of the 2019 Lao PDR ASF epidemic in domestic pigs, identify environmental (protected areas and forests), production (pig ownership), transportation (roads), and social (poverty and ethnicity) risk factors, and recommend measures that could reduce ASF spread. A retrospective spatiotemporal study was conducted at the village level. Information on the date that ASF was first reported from each case location was collected, and the outcome variable of interest “epidemic day” was created. Risk factor information from different sources was extracted for each case location. The association or correlation between epidemic day and risk factors for the spread of ASF was investigated using Kruskal–Wallis tests and Spearman rank correlation statistics. The epidemic started on June 16 and lasted for 190 days, displaying a right-skewed epidemic curve. The directional distribution was rotated approximately 305°, from Southeast to Northwest Laos. Significant risk factors for ASF associated with epidemic day were location in terms of distance from the closest protected natural area P = 0.020 , pig ownership P = 0.005 , road networks P = 0.003 , and poverty indices P &lt; 0.001 . Cases were reported earlier in this epidemic at locations that were closer to protected natural areas, of higher pig ownership, more connected via the national road network, and which experienced elevated poverty. The spatiotemporal pattern described suggests that ASF was introduced via infected pigs from Vietnam. Based on study findings, recommendations for smallholder pig production in Southeast Asia include improving knowledge of swine value chains to inform disease risk and control, monitoring pig transportation, implementing stricter biosecurity measures on the domestic pig population, and providing biosecurity support and education to smallholder pig farmers in poverty.

Evaluation of Biosecurity Measures in Pig Holdings in Slovenia as a Risk Assessment for the Introduction of African Swine Fever Virus.

African Swine Fever (ASF) is persistently spreading and hindering pork production in Europe. Slovenia is one of the last countries in Central Europe without a confirmed ASF case in domestic pigs or in wild boar. The aim of this study was to assess the current biosecurity implementation on different types of pig farms. Internal and external biosecurity status was determined in 17 commercial (CF), 15 non-commercial (NC), and 15 outdoor (O) farms. Data were collected using the Biocheck.UGent questionnaire and assessed in combination with the latest information on the wild boar population in Slovenia. Biosecurity was compared between farm types based on the assessment of 12 subcategories. Statistically significant differences (p < 0.05) were found in six subcategories: (i) purchase of pigs and semen, (ii) visitors and farmworkers, (iii) vermin and bird control, (iv) finishing unit, (v) measures between compartments and use of equipment, and (vi) cleaning and disinfection. The highest total biosecurity score (0-100%) was determined on CF with 64.59 ± 16.47%, followed by NC with 55.73 ± 10.67%, and O with 48.47 ± 8.20%. The density of the wild boar population was estimated from the number of wild boars per km2 per year, with 3 or more hunted wild boars per unit representing the highest density. Geolocation of farms on the wild boar population map showed that two O farms are at high risk and seven farms (1 O, 5 NC, and 1 CF) are at medium risk for disease transmission from wild to domestic pigs. Biosecurity measures must be tightened in some subcategories, especially in areas with a high density of wild boar.

Genomics Insight into cfr-Mediated Linezolid-Resistant LA-MRSA in Italian Pig Holdings

The cfr genes encode for a 23S rRNA methyltransferase, conferring a multiresistance phenotype to phenicol, lincosamide, oxazolidinone, pleuromutilin, and streptogramin A antibiotics. These genes have been described in staphylococci, including methicillin-resistant Staphylococcus aureus (MRSA). In this study, we retrospectively performed an in-depth genomic characterisation of three cfr-positive, multidrug-resistant (MDR) livestock-associated (LA) MRSA clonal complexes (CCs) 1 and 398 detected in different Italian pig holdings (2008-2011) during population studies on Italian livestock (2008-2014). We used a combined Illumina and Oxford Nanopore Technologies (ONT) whole genome sequencing (WGS) approach on two isolates (the 2008 CC1 and the 2010 CC398 isolates, but not the 2011 CC1 isolate). Interestingly, the three isolates presented different cfr variants, with only one displaying a linezolid-resistant phenotype. In isolate 2008 CC1, the cfr gene was identified within a Tn558 composite transposon-like structure flanked by IS elements located on a novel 44,826 bp plasmid. This represents the first report of CC1 LA-MRSA harbouring the cfr gene in its functional variant. Differently, cfr was chromosomally located in isolate 2010 CC398. Our findings have significant public health implications, confirm the need for the continuous genomic surveillance of cfr-positive zoonotic LA-MRSA, and backdate cfr presence in LA-MRSA from Italian pigs to at least 2008.

The hazard of carbapenemase (OXA-181)-producing Escherichia coli spreading in pig and veal calf holdings in Italy in the genomics era: Risk of spill over and spill back between humans and animals.

Carbapenemase-producing Enterobacterales (CPE) are considered a major public health issue. In the frame of the EU Harmonized AMR Monitoring program conducted in Italy in 2021, 21 epidemiological units of fattening pigs (6.98%; 95% CI 4.37-10.47%; 21/301) and four epidemiological units of bovines <12 months (1.29%; 95% CI 0.35-3.27%, 4/310) resulted positive to OXA-48-like-producing E. coli (n = 24 OXA-181, n = 1 OXA-48). Whole Genome Sequencing (WGS) for in-depth characterization, genomics and cluster analysis of OXA-181-(and one OXA-48) producing E. coli isolated, was performed. Tracing-back activities at: (a) the fattening holding of origin of one positive slaughter batch, (b) the breeding holding, and (c) one epidemiologically related dairy cattle holding, allowed detection of OXA-48-like-producing E. coli in different units and comparison of further human isolates from fecal samples of farm workers. The OXA-181-producing isolates were multidrug resistant (MDR), belonged to different Sequence Types (STs), harbored the IncX and IncF plasmid replicons and multiple virulence genes. Bioinformatics analysis of combined Oxford Nanopore Technologies (ONT) long reads and Illumina short reads identified bla OXA-181 as part of a transposon in IncX1, IncX3, and IncFII fully resolved plasmids from 16 selected E. coli, mostly belonging to ST5229, isolated during the survey at slaughter and tracing-back activities. Although human source could be the most likely cause for the introduction of the bla OXA-181-carrying IncX1 plasmid in the breeding holding, concerns arise from carbapenemase OXA-48-like-producing E. coli spreading in 2021 in Italian fattening pigs and, to a lesser extent, in veal calf holdings.

Molecular Epidemiology Questions Transmission Pathways Identified During the Year 2000 Outbreak of Classical Swine Fever in the UK.

The last outbreak of classical swine fever (CSF) in the UK occurred in 2000. A total of 16 domestic pig holdings in the East Anglia region were confirmed as infected over a 3-month period. Obtaining viral genome sequences has since become easier and more cost-effective and has accordingly been applied to trace viral transmission events for a variety of viruses. The rate of genetic evolution varies for different viruses and is influenced by different transmission events, which will vary according to the epidemiology of an outbreak. To examine if genetic changes over the course of any future CSF outbreak would occur to supplement epidemiological investigations and help to track virus movements, the E2 gene and full genome of the virus present in archived tonsil samples from 14 of these infected premises were sequenced. Insufficient changes occurred in the full E2 gene to discriminate between the viruses from the different premises. In contrast, between 5 and 14 nucleotide changes were detected between the genome sequence of the virus from the presumed index case and the sequences from the other 13 infected premises. Phylogenetic analysis of these full CSFV genome sequences identified clusters of closely related viruses that allowed to corroborate some of the transmission pathways inferred by epidemiological investigations at the time. However, other sequences were more distinct and raised questions about the virus transmission routes previously implicated. We are thus confident that in future outbreaks, real-time monitoring of the outbreak via full genome sequencing will be beneficial.

Development of African Swine Fever in Poland

African swine fever (ASF) is a major problem in the production of live pigs in many EU countries. The aim of this research is to identify the causes and effects of this disease in Poland. The study used data from various institutions in Poland and from the EU Animal Diseases Information System (ADIS). Within the range of causes for ASF development, we considered the transmission of the ASF virus by wild boars and human activity. The article presents the number and distribution of ASF cases in wild boars, and the outbreaks of ASF in domestic pigs, in the years 2014–2020. The relationship between these variables was determined with a rectilinear regression analysis. The analysis of data for poviats where ASF cases in wild boards and ASF outbreaks in domestic pigs have been reported shows a certain periodicity of ASF occurrence in the country. This research shows that, despite the actions taken by veterinary services, hunting associations and the involvement of state administration bodies, the disease spreads rapidly. The occurrence of ASF outbreaks in domestic pigs concerns both small and large scale farms. However, due to the fragmented nature of pig farming in Poland, ASF is more prevalent in smaller holdings. Among the main reasons for the development of this disease in the country are the insufficient bio-insurance coverage of pig holdings, and the presence of the virus in the wild boar population. The process of ridding the country of the ASF virus is long and costly.

Efficient inactivation of African swine fever virus by a highly complexed iodine

African swine fever (ASF) is a highly lethal contagious disease of swine caused by African swine fever virus (ASFV). Cleaning and disinfection remain one of the most effective tools to prevent the ASFV spread in pig holdings. This study evaluated the inactivation effect of a highly complexed iodine (HPCI) disinfectant against ASFV. A commercially available povidone-iodine (PVP-I) was used as reference for comparison. The results showed that 5% HPCI and 5% PVP-I did not exhibit cytotoxicity in primary porcine alveolar macrophages, and 107.0 and 105.0 TCID50/mL ASFV were completely inactivated by 5% and 0.25% HPCI, respectively, in 5 min via either immersion or spray disinfection. However, 5% PVP-I required at least 15 min to completely inactivate 107.0 TCID50/mL ASFV, whereas 0.25% PVP-I failed to completely inactivate 105.0 TCID50/mL ASFV. This study demonstrated that HPCI could rapidly and efficiently inactivate ASFV, representing an effective disinfectant for ASF control.

Emergence of African Swine Fever in Poland (2014–2021). Successes and Failures in Disease Eradication

African swine fever (ASF) in Poland has been a major concern for pig production for the last seven years. The main constrains in ASF eradication in Poland are due to the high density of wild boar in ASF-affected areas of the country. Other factors, responsible for long-distance ASF spread to new regions of the country, are mainly related to human-mediated activity and lack of awareness of the potential disease threat to pig production. In the case of pig holdings, the only effective measure of ASF prevention is strict implementation of biosecurity rules. Despite many efforts to implement these measures, the disease occurred in a number of voivodeships, poviats and counties of Poland, primarily in eastern Poland; however, starting from 2019, also in the western part of the country. Further recommendations to eradicate ASF in Poland or at least to minimize the economic loss caused by ASF in pig production include effective wild boar population management strategies along with the implementation of strict biosecurity measures. The observations from the last seven years of ASF epizootic in Poland clearly indicate that the disease could not have been effectively controlled in wild boar population and could only be restricted in domestic pig population following severe biosecurity rules. As for ASF spread control in wild boar population, the measures applied in other EU countries include active wild boar carcass search and disposal along with sanitary and reduction hunting. These measures have also been shown non-effective. The only solution for future sustainable pig production in Poland seems to be strict collaboration between pig producers, veterinary inspection, and hunting associations.

Research priorities to fill knowledge gaps in the control of African swine fever: possible transmission of African swine fever virus by vectors.

The European Commission requested that EFSA provide study designs for the investigation of four research domains according to major gaps in knowledge identified by EFSA in a report published in 2019: (i) the patterns of seasonality of African Swine Fever (ASF) in wild boar and domestic pigs in the EU; (ii) the epidemiology of ASF in wild boar; (iii) survival of ASF virus (ASFV) in the environment and (iv) transmission of ASFV by vectors. In this Scientific Opinion, the fourth research domain on ASFV transmission by vectors is addressed. Eleven research objectives were proposed by the EFSA working group and broader ASF expert networks, such as ASF stop, ENETWILD, VectorNet, AHAW network and the AHAW Panel Experts. Of the 11 research objectives, six were prioritised based on the following set of criteria: (1) the impact on ASF management; (2) the feasibility or practicality to carry out the study; (3) the potential implementation of study results in practice; (4) a possible short time‐frame study (< 1 year); (5) the novelty of the study and (6) if it was a priority for risk managers. The prioritised research objectives were: (I) Studies on the potential vector fauna at the pig–wild boar interface and the feeding preference of blood‐feeding potential vectors in ASF‐affected areas; (II) Assessment of the efficacy of insect screens on indoor/outdoor pig holdings to prevent the entry of blood‐sucking vectors (i.e. Stomoxys) in ASF endemic areas; (III) Assess the role of mechanical vectors in the virus transmission in ASF‐affected areas; (IV) Distribution of the potential mechanical transmission vectors in ASF‐affected areas of the EU; (V) ASFV transmission by synanthropic birds; and (VI) Assessment on the presence/absence of the soft tick Ornithodoros erraticus in ASF‐affected areas in Europe. For each of the selected research objectives, a research protocol has been proposed considering the potential impact on ASF management and the period of 1 year for the research activities.

The Addition of Nature Identical Flavorings Accelerated the Virucidal Effect of Pure Benzoic Acid against African Swine Fever Viral Contamination of Complete Feed.

Simple SummaryThe African swine fever (ASF) virus is one of the deadliest viruses plaguing the global swine industry. There are no effective treatments for pigs becoming infected with the ASF virus. Eliminating infected pigs is the only effective method to tackle an outbreak. Whole farm biosecurity is therefore critical to prevent the virus from entering in the first place. In recent years, feed and feed ingredients have been identified as potential vectors of viral diseases including ASF. The objective of this research was to simulate contamination of feed by ASF virus in a laboratory setting and use this simulation to test the efficacy of some select feed additives for reducing the amount and viability of this virus in feed. The main result shows that the inoculated virus in feed disappeared in a shorter time when the feed had been treated with the compounds. We conclude that these feed additives could be adopted as part of a comprehensive biosecurity system for pig holdings. Pigs might be protected from feed possibly contaminated by this virus, and the pork supply will thus be less likely to be impacted by this viral disease.African swine fever virus is one of the most highly contagious and lethal viruses for the global swine industry. Strengthening biosecurity is the only effective measure for preventing the spread of this viral disease. The virus can be transmitted through contaminated feedstuffs and, therefore, research has been conducted to explore corresponding mitigating measures. The purpose of the current study was to test a combination of pure benzoic acid and a blend of nature identical flavorings for their ability to reduce African swine fever viral survival in feed. This virus was inoculated to feed with or without the supplementation of the test compounds, and the viral presence and load were measured by a hemadsorption test and quantitative real time polymerase chain reaction. The main finding was that the combination of pure benzoic acid and nature identical flavorings could expedite the reduction in both viral load and survival in a swine feed. Therefore, this solution could be adopted as a preventive measure for mitigating the risk of contaminated feed by African swine fever virus.

Semi-quantitative risk assessment by expert elicitation of potential introduction routes of African swine fever from wild reservoir to domestic pig industry and subsequent spread during the Belgian outbreak (2018-2019).

Since the introduction in Georgia in 2007 of an African swine fever (ASF) genotype 2 virus strain, the virus has rapidly spread to both Western European and Asian countries. It now constitutes a major threat for the global swine industry. The ongoing European transmission cycle has been related to the 'wild boar habitat' with closed transmission events between wild boar populations and incidental spillovers to commercial and non-commercial (backyard) pig holdings. During the epidemic in Belgium, only wild boar were infected and although the introduction route has not yet been elucidated, the 'human factor' is highly suspected. While ASF was successfully contained in a small region in the Southern part of Belgium without affecting domestic pigs, the risk of spillover at the wild/domestic interface remains poorly assessed. In this study, we used a semi-quantitative method, involving national and international experts, to assess the risk associated with different transmission routes for ASF introduction from wild boar to domestic pig holdings and subsequent dissemination between holdings in the Belgian epidemiological context. Qualitative responses obtained by our questionnaire were numerically transformed and statistically processed to provide a semi-quantitative assessment of the occurrence of the hazard and a ranking of all transmission routes. 'Farmer', 'bedding material', 'veterinarian' and 'professionals from the pig sector' were considered as the most important transmission routes for ASF introduction from the wild reservoir to pig holdings. 'Animal movements', 'farmer', 'veterinarian', 'iatrogenic', 'animal transport truck' and 'animal care equipment' were considered as the most important transmission routes posing a risk of ASF spread between pig holdings. Combined with specific biosecurity checks in the holdings, this assessment helps in prioritizing risk mitigation measures against ASF introduction and further spread in the domestic pig industry, particularly while the ASF situation in Western Europe is worsening.

The detection of Japanese encephalitis virus in Megachiropteran bats in West Kalimantan, Indonesia: A potential enzootic transmission pattern in the absence of pig holdings

The West Kalimantan province in Borneo island, Indonesia belongs to endemic area of Japanese encephalitis (JE) that accounts for approximately 30% of total cases yearly. As the presence of pig holdings is uncommon in West Kalimantan, another reservoir host might have played a role in the local transmission of JE virus in this area. Current study aimed to identify the potential role of bats in the local transmission of JE by performing molecular detection of JE virus in bats and mosquitoes using RT-PCR. Sample collection was performed in 3 districts in West Kalimantan, covering 3 different ecosystems: forest, coastal, and residential areas. Bat collection was performed using mist net and harp net, while mosquito collection was carried out using animal-baited trap and human landing collection. A total of 373 blood samples from bats were tested for JE virus, among which 21 samples (5.6%) showed positive results, mainly from Cynopterus brachyotis (lesser short-nosed fruit bat) found in residential areas. Out of 53 mosquito pools, 3 JE-positive pools of Culex tritaeniorhynchus and Cx. vishnui were collected at the same location as JE-positive bats. Current study showed the first evidence of JE virus detection in several species of Megachiropteran bats in Indonesia, demonstrated the potential role of frugivorous bats in local transmission of JE in West Kalimantan. More aggressive measures are required in JE risk mitigation, particularly in initiating JE vaccination campaign and in avoiding disruption of bats’ natural habitats through changes in land-use.

ASSESSMENT OF ANTIMICROBIALS USAGE IN COMMERCIAL FARROW-TO-FINISH PIG HOLDINGS IN VOJVODINA REGION (SERBIA)

The pig production is considered to be amongst the animal husbandry sectors with the highest antimicrobial usage. In Serbia, antimicrobials have wide application at pig farms as therapeutic but also as a prophylactic treatment. The aim of the research study was assessment of the antimicrobial usage in different stages of pig production in commercial farrow to-finish pig holdings located in Vojvodina Province (Serbia). In the research a total eleven pig holdings located in the Vojvodina Province were included. All investigated herds were single site farrow-to-finish production systems with minimum of 300 sows in the site. The data on prophylactic and therapeutic measures on the investigated farms were obtained from official farm treatment records provided by the veterinarians and/or farmers. The antimicrobials usage on the pig farms was recorded by product, administration route and animal production category. Analysis of recorded data revealed that different types of antimicrobials from almost all groups are applied. Breeding pigs (sows, boars) received less treatment compared to growing categories. Regarding different antimicrobials, a frequent use of cephalosporins and polymyxins applied to growing piglets was detected. The group treatments were mostly preventive and antimicrobial usage often lack prior a precise diagnosis. The high amounts of macrolides and pleuromutilins (tiamulin), quite often in combination with tetracycline’s in fattening stage were notified. In conclusion, the significant level of prophylactic antimicrobial treatments in farrow-to-finish pig farms in Serbia is evident. The present study was initiated as a first step for comparing antimicrobial usage on herd level using available data.&#x0D;

Using network analysis to identify seasonal patterns and key nodes for risk‐based surveillance of pig diseases in Italy

The description of the pattern of livestock movements between herds provides essential information for both improving risk-based surveillance and to understand the likely spread of infectious diseases. This study provides a description of the temporal pattern of pig movements recorded in Italy on a 4-year period (2013-2016). Data, provided by the National Livestock registry, were described by social network analysis and the application of a walk-trap algorithm for community detection. Our results show a highly populated community located in Northern Italy, which is the focal point of the Italian industrial pig production and as a general pattern an overall decline of medium and backyard farms and an increase in the number of large farms, in agreement with the trend observed by other EU pig-producing countries. A seasonal pattern of all the parameters evaluated, including the number of active nodes in both the intensive and smaller production systems, emerged: that is characterized by a higher number of movements in spring and autumn, linked with the breeding and production cycle as pigs moved from the growing to the finishing phase and with periods of increased slaughtering at Christmas and Easter. The same pattern was found when restricting the analysis to imported pig batches. Outbreaks occurring during these periods would have a greater impact on the spread of infectious diseases; therefore, targeted surveillance may be appropriate. Finally, potential super-spreader nodes have been identified and represent 0.47% of the total number of pig holdings (n=477). Those nodes are present during the whole study period with a similar ranking in their potential of being super-spreaders. Most of them were in Northern Italy, but super-spreaders with high mean out-degree centrality were also located in other Regions. Seasonality, communities and super-spreaders should be considered when planning surveillance activity and when applying disease control strategies.