Detection and characterisation of porcine circoviruses in wild boars in northeastern Serbia

The objective was to expand and update the knowledge on the presence and genotype diversity of porcine circoviruses 2 and 3 (PCV2 and PCV3) in the wild boar populations from the hunting grounds in northeastern Serbia. The presence of PCV3 was not determined, and PCV2 was confirmed in 40.32% of the organ samples from 124 wild boars hunted from 2018 to 2019, indicating their significance in virus circulation since traditional pig farms with irregular PCV2 vaccination strategies are widespread in this region. The most prevalent genotype was PCV2d, followed by PCV2b and PCV2a in 55.6%, 38.9%, and 5.5% of the examined samples, respectively. Nucleotide sequences of the detected strains were homogenous within the genotype and clustered within the subgroups PCV2d-2, PCV2b-1A/B, and PCV2a-2D with high identity to European, Chinese, and Serbian domestic pig sequences suggesting their origin. Wild boars presented with no clinical or pathological signs of infection, implying that these animals might be less susceptible to disease, particularly since the cofactors present in pig farming systems that support the disease development are absent in the wild. The high PCV2 detection frequency demonstrates the importance of wildlife monitoring to track virus population dynamics, especially in regions with free-range pig farming in order to plan adequate disease control strategies.

African Swine Fever Outbreaks in Lithuanian Domestic Pigs in 2019

While numerous risk factors of African swine fever (ASF) transmission to domestic pigs have been described, ASF virus introduction has often not been traced back to one single defined cause. The large number of ASF outbreaks that occurred in domestic pigs in Lithuania from 2014 through to 2018 raised the question regarding whether outbreak-specific risk factors and transmission routes could be identified. Therefore, a prospective matched case-control study was designed. Data from 18 outbreaks that occurred in Lithuanian in 2019 and 36 control farms were analyzed. Conditional multivariable logistic regression showed that two or more visits by veterinary inspection of a farm had a significant preventive effect on the occurrence of ASF on a farm (Odds ratio (OR) 14.21, confidence interval (CI) 1.09–185.60 for farms not inspected vs. farms inspected twice or more a year), while certain practices (e.g., mushroom picking, sharing equipment, etc.), which might facilitate the indirect introduction of ASF from fields and forests into piggeries, significantly increased the odds of an outbreak (OR 5.18, CI 1.10–24.44). The results of the study highlight the importance of veterinary inspections for increasing the biosecurity level on pig farms and the awareness of ASF. The knowledge on potential protective and risk factors may help to improve the prevention and control of ASF outbreaks in domestic pig farms in Lithuania and other affected countries.

Biosecurity Levels and Farm Characteristics of African Swine Fever Outbreak and Unaffected Farms in Estonia—What Can Be Learned from Them?

Risk factors related to external biosecurity have been considered to play a major role in the introduction and spread of African swine fever (ASF) in domestic pig populations. The aim of the study was to describe the biosecurity levels and management practices of ASF outbreak and uninfected herds and to identify potential risk factors for ASF introduction. Data collected from the outbreak herds during outbreak investigations and from the randomly selected uninfected herds were analyzed. The biosecurity score in ASF outbreak herds was significantly lower compared to uninfected herds. However, this may reflect general improvement in the application of biosecurity measures in pig farms over time as the data on uninfected herds were collected later, at a time when intensified official controls may have had their effect. Larger herds were more at risk of being outbreak herds compared to smaller herds. The biosecurity parameters significantly associated with the outbreak herd status in multiple correspondence analysis were mostly related to indirect contacts with the outside farm environment. The biosecurity barriers applied in Estonian pig farms have not been sufficient to avoid ASF introduction and need critical evaluation and improvement. Reduction of all contacts between the farm and the external environment should be emphasized in a situation where ASF is circulating in wild boar populations close to pig farms.

The Organization of the Pig T-cell Receptor Gamma (TRG) Locus Provides Insights Into the Evolutionary Patterns of the TRG Genes Across Cetartiodactyla

The domestic pig (Sus scrofa) is a species representative of the Suina, one of the four suborders within Cetartiodactyla. In this paper, we reported our analysis of the pig TRG locus in comparison with the loci of species representative of the Ruminantia, Tylopoda and Cetacea suborders. The pig TRG genomic structure reiterates the peculiarity of the organization of Cetartiodactyla loci in TRGC “cassettes”, each containing the basic V-J-J-C unit. Eighteen genes arranged in four TRGC cassettes, form the pig TRG locus. All the functional TRG genes were expressed, and the TRGV genes preferentially rearrange with the TRGJ genes within their own cassette, which correlates the diversity of the gamma-chain repertoire with the number of cassettes. Among them, the TRGC5, located at the 5’ end of the locus, is the only cassette that retains a marked homology with the corresponding TRGC cassettes of all the analyzed species. The preservation of the TRGC5 cassette for such a long evolutionary time presumes a highly specialized function of its genes, which could be essential for the survival of species. Therefore, the maintenance of this cassette in pigs confirms that it is the most evolutionarily ancient within Cetartiodactyla, and it has undergone a process of duplication to give rise to the other TRGC cassettes in the different artiodactyl species in a lineage-specific manner.

A methodology to assess indirect economic impacts of animal disease outbreaks

Indirect costs of animal disease outbreaks often significantly exceed the direct costs. Despite their importance, indirect costs remain poorly characterised due to their complexity. In this study, we developed a framework to assess the indirect costs of a hypothetical African Swine Fever outbreak in Switzerland. We collected data through international and national stakeholder interviews, analysis of national disease control regulations and industry data. We developed a framework to capture the resulting qualitative and quantitative data, categorise the impacts of these regulations, and rank the impacts in order of importance. We then developed a spreadsheet model to calculate the indirect costs of one category of control measure for an individual group of stakeholders. We developed a decision tree model to guide the most economically favourable implementation plan for a given control measure category, under different outbreak scenarios. Our results suggest that the most important measure/impact categories were ‘Transport logistics’, ‘Consumer demand’, ‘Prevention of wild boar and domestic pig contact’ and ‘Slaughter logistics’. In our hypothetical scenario, the greatest costs associated with ‘Prevention of wild boar and domestic pig contact’ were due to assumed partial or total depopulation of pig farms in order to reduce herd size to comply with the simulated control regulations. The model also provides suggestions on the most economically favourable strategy to reduce contact between wild boar and domestic pigs in control areas depending on the duration of the outbreak. Our approach provides a new framework to integrate qualitative and quantitative data to guide disease control strategy. This method could be useful in other countries and for other diseases, including in data- and resource-poor settings, or areas with limited experience of animal disease outbreaks.

Genome Assemblies of the Warthog and Kenyan Domestic Pig Provide Insights into Suidae Evolution and Candidate Genes for African Swine Fever Tolerance

As warthog (Phacochoerus africanus) has innate immunity against African swine fever (ASF), it is critical to understanding the evolutionary novelty of warthog to explain its specific ASF resistance. Here, we present two completed new genomes of one warthog and one Kenyan domestic pig, as the fundamental genomic references to decode the genetic mechanism on ASF tolerance. Our results indicated, multiple genomic variations, including gene losses, independent contraction and expansion of specific gene families, likely moulded warthog's genome to adapt the environment. Importantly, the analysis of presence and absence of genomic sequences revealed that, the warthog genome had a DNA sequence absence of the lactate dehydrogenase B (LDHB) gene on chromosome 2 compared to the reference genome. The overexpression and siRNA of LDHB indicated that its inhibition on the replication of ASFV. The Combining with large scale sequencing data of 123 pigs from all over world, contraction and expansion of TRIM genes families revealed that TRIM family genes in the warthog genome were potentially responsible for its tolerance to ASF. Our results will help further improve the understanding of genetic resistance ASF in pigs.

Key risk factors and impact of African swine fever spreading on pig production in Serbia

African swine fever (ASF) is a viral disease of domestic pigs and wild boars and currently represents a major threat to the swine industry worldwide. Disease control is impaired by a lack of an effective vaccine and currently, it is dependent on biosecurity measures in pig production, rapid diagnosis, and stamping out of infected herds. Consequently, this swine disease has considerable social-economic significance on national or even regional level. In 2019 for the first time ASF was detected in the domestic swine population (backyards) in the central region of Serbia. From then on, there have been continuous outbreaks of new cases in the population of domestic and wild boars. Considering domestic pig population, in the majority of cases, ASF was detected in small holdings and backyards. The biosecurity measures are not officially required by veterinary regulation and are only given in a form of recommendations. On the other hand, it is not always possible to implement biosecurity measures that are recognized today as essential for sustainable pig production in the old type of industrial pig facilities. Nowadays, in 2021, it became obvious that the domestic pig cycle, human activities involving pigs, or pig-derived meat products are the dominant driver of virus transmission. Additionally, human activities are frequently a risky connection between domestic pigs and wild boars both directly or indirectly. Traditional, culture-related aspects and facts that politicians failed to recognise ASF as a serious issue that causes great economical losses were found to be very important obstacles in disease control.

Multimodal characterization of Yucatan minipig behavior and physiology through maturation

Brain injuries induced by external forces are particularly challenging to model experimentally. In recent decades, the domestic pig has been gaining popularity as a highly relevant animal model to address the pathophysiological mechanisms and the biomechanics associated with head injuries. Understanding cognitive, motor, and sensory aspects of pig behavior throughout development is crucial for evaluating cognitive and motor deficits after injury. We have developed a comprehensive battery of tests to characterize the behavior and physiological function of the Yucatan minipig throughout maturation. Behavioral testing included assessments of learning and memory, executive functions, circadian rhythms, gait analysis, and level of motor activity. We applied traditional behavioral apparatus and analysis methods, as well as state-of-the-art sensor technologies to report on motion and activity, and artificial intelligent approaches to analyze behavior. We studied pigs from 16 weeks old through sexual maturity at 35 weeks old. The results show multidimensional characterization of minipig behavior, and how it develops and changes with age. This animal model may capitulate the biomechanical consideration and phenotype of head injuries in the developing brain and can drive forward the field of understanding pathophysiological mechanisms and developing new therapies to accelerate recovery in children who have suffered head trauma.