Anna Szczotka-Bochniarz

Introduction: This study assessed the seroprevalence of Aujeszky’s disease virus (ADV), Coxiella burnetii and Chlamydia spp. in wild boars in Poland. Material and Methods: A total of 1,094 serum samples were tested. Antibodies against ADV were detected by ELISA, whereas Chlamydia spp. and C. burnetii were detected using the complement fixation test (CFT). For C. burnetii , phase I and phase II antibodies were assessed by CFT to differentiate between long-term and recent exposure. Multiple correspondence analysis was performed to evaluate associations between seropositivity, geographical origin and wild boar population density. Serological data were integrated with environmental factors, including African swine fever (ASF) occurrence, population density and forest cover, and were visualised spatially. Results: Antibodies against ADV were detected in 455 samples (41.6%), those against Chlamydia spp. in 70 (6.4%) and antibodies against phase-I C. burnetii in 37 (3.4%) and phase-II in 30 (2.7%). Associations were observed between antibody presence, geographical location, wild boar density, pathogen co-occurrence and ASF-related environmental variables. Conclusion: Wild boars in Poland show serological evidence of exposure to ADV, Chlamydia spp. and C. burnetii , supporting their role as sentinels at the wildlife–livestock interface.

Introduction: Copper (Cu) deficiency is a common, often subclinical problem in dairy cattle herds that can adversely affect haematopoietic processes and immune function. This study aimed to evaluate the effect of hypocupraemia in cows on selected haematological parameters and identify the immunophenotype of calf lymphocytes. Material and Methods: The study included Holstein–Friesian cows and their calves aged two to six weeks, which were divided into two groups: a hypocupraemic group (17 cows and 17 calves) and a normocupraemic group (18 cows and 18 calves). Haematological and biochemical analyses were performed, and lymphocyte subpopulations (CD4 ⁺ , CD8 ⁺ , CD21 ⁺ and major histocompatibility complex (MHC) class II ⁺ were determined by flow cytometry. Results: Cows with hypocupraemia exhibited reduced HGB and HCT values. Calves born to cows with Cu deficiency showed decreased erythrocyte indices, a reduced CD4 ⁺ :CD8 ⁺ ratio and a lower percentage of CD21 ⁺ B lymphocytes and MHC class II ⁺ lymphocytes, indicating impaired immune function. In these calves, the CD4 ⁺ :CD8 ⁺ ratio was significantly lower compared to healthy cows and calves, suggesting an imbalance in T-lymphocyte subpopulations. Conclusion: The obtained results indicate that even moderate copper deficiency in pregnant cows may negatively influence the haematological and immunological status of their offspring. These findings underline the necessity of systematic monitoring of copper status in dairy herds in order to prevent subclinical deficiencies and their long-term consequences for calf health and immunity.

To investigate potential husbandry‐related risk factors for African swine fever (ASF) incursion on commercial pig farms in Lithuania, Poland, and Romania, a prospective, matched case–control design was carried out from August 2021 to September 2023. For each participating commercial pig farm where an ASF outbreak occurred, two control farms were randomly selected and matched by herd size and county. On both case and control farms, questionnaires related to farm management and biosecurity measures were carried out, and stable flies ( Stomoxys calcitrans ) and biting midges (Culicoides spp.) were collected to identify a possible association between the number of ASF virus (ASFV)‐ or ASFV DNA‐positive vectors and presence of ASF on the farms. After testing for potential multicollinearity, a conditional logistic regression model was performed on one complete and three imputed datasets. To evaluate the best‐fit model, the Akaike information criterion (AIC) method was used. This study generated more knowledge on risk and protective factors for ASF introduction on commercial pig farms related to (1) farm location (risk: closer distance to ASF outbreaks); (2) the wild boar (WB)–pig interface (risk: attractive crops for WB cultivated near the farms); (3) biosecurity (protective: carcasses collection by the rendering company without entering the holding and closed containers for carcass disposal, risk: sharing machinery with other farms or organizing unusual events on the farm); (4) insect‐mediated mechanic transmission (protective: placement of insect screens on all doors and windows and risk: the number of biting midges collected on the farm). Manure from other holdings applied on the soil near the farm was in two of four models found significant and could be related to possible mechanical transmission by stable flies or to an increased infection pressure. Some of the identified husbandry‐related risks and protective factors can have a direct practical value for the farmers.

This review synthesizes current knowledge on the risks posed by viral foodborne infections associated with pork, emphasizing their global prevalence and the complexity of managing such pathogens. It covers a range of significant viruses, including hepatitis A and E, norovirus, rotavirus, sapovirus, enterovirus, astrovirus, and enteric adenovirus. The role of pigs as reservoirs for diverse pathogens with zoonotic potential further complicates safety challenges, extending risks to individuals involved in pork production and processing. Various factors influencing viral contamination throughout the meat production chain are explored, from farm-level practices to processing and handling procedures. Emphasis is placed on the critical importance of implementing effective control measures at each stage, including enhanced biosecurity, rigorous hygiene practices, and appropriate thermal processing techniques. Additionally, the need for improved surveillance and detection methods to effectively identify and monitor viral presence in meat products is highlighted. In conclusion, the necessity of adopting a One Health approach that integrates efforts in animal health, food safety, and public health to mitigate the risks of viral foodborne infections associated with meat consumption is underscored. This holistic strategy is essential for safeguarding consumer health and ensuring the safety of the global food supply.

Human health is dependent on food safety and, therefore, on the health of farm animals. One of the most significant threats in regard to swine diseases is African swine fever (ASF). Infections caused by porcine circoviruses (PCVs) represent another important swine disease. Due to the ubiquitous nature of PCV2, it is not surprising that this virus has been detected in ASFV-affected pigs. However, recent data indicate that coinfection of PCV3 and ASFV also occurs. It is still unclear whether PCV infection plays a role in ASFV infection, and that subject requires further analysis. The aim of this study was to assess whether PCV3 and PCV4 are present in the wild boar population in Poland (real-time PCR). The analysis was performed on wild boar samples collected for routine ASF surveillance in Poland, between 2018 and 2021. By extension, the obtained data were compared in regard to ASFV presence in these samples, thus investigating the odds of ASFV infection on the grounds of the PCV carrier state in free-ranging Suidae in Poland. In addition, sequencing of PCV3 and phylogenetic analysis were performed, based on a full genome and a capsid gene. In the current study, we demonstrated the high prevalence of PCV3 in the wild boar population in Poland; meanwhile, PCV4 was not detected. The odds of ASFV infection on the grounds of the PCV3 carrier state in free-ranging Suidae in Poland was more than twice as high. Ten full genome sequences of PCV3 were obtained, all of them belonging to clade 3a. The similarity between them was in the range of 98.78–99.80%.

Introduction: The molecular contamination of an animal facility was investigated during and after an infection with highly pathogenic African swine fever virus (ASFV) among domestic pigs. The investigation evaluated the risk of indirect transmission of the disease and indicated points that may facilitate cleaning and disinfection processes. Material and Methods: Six domestic pigs were infected oronasally with the highly pathogenic Georgia 2007 strain. Environmental samples from the floors, walls, rubber floor mats, feeders, drinkers, high-efficiency particulate-absorbing filter covers and doors were collected 7 days post infection (dpi), 7 days later and 24 h after disinfection of the facility. The samples were investigated by real-time PCR and in vitro assays to find genetic traces of ASFV and infectious virus. Results: Typical clinical outcomes for ASF (i.e. fever, apathy, recumbency and bloody diarrhoea) were observed, and all animals died or required euthanasia before or at 9 dpi. No infectious virus was found in environmental samples at the sampling time points. Genetic traces of ASFV were found in all locations except the doors. The initial virus load was calculated using real-time PCR threshold cycle values and was the highest at the drain. A statistically significant decrease of virus load over time was found on non-porous surfaces mechanically cleaned by water (the floor and drain). Conclusion: The gathered data confirmed different routes of virus excretion (oral and nasal, faeces and urine, and aerosol) and showed virus locations and different initial concentrations in the animal facility. Maintaining the facility with mechanical cleaning and using personal protection (gloves) and hand disinfection may efficiently minimise the risk of further virus spread. Together with the results of previously published studies, the present investigations’ failure to isolate infectious virus may suggest that if stable environmental conditions are assured, the time needed before the introduction of new herds into previously ASF-affected farm facilities could be shortened and in this way the economic losses caused by the disease outbreak mitigated.

African swine fever remains one of the most economically important and dangerous diseases of the Suidae family. Until now, neither a safe vaccine nor a treatment against ASF has been available, which is why prevention of the disease involves biosecurity measures and early recognition based on accurate diagnosis. Nowadays, different strategies for ASF detection are discussed to reduce both animal suffering and the costs of ASF surveillance. This article aims to indicate the risk, with regard to non-invasive sampling, for the detection of ASFV. In this study, we analyzed data from three independent animal trials, in the framework of the detection of positive samples in different matrices (blood, sera, oral and rectal swabs) collected from nineteen domestic pigs infected with similar doses but under different scenarios, including different ASFV strains or routes of infection. Genetic material of ASFV was found in all matrices, but detection occurred earlier in the blood samples than in the oral and the rectal swabs. Furthermore, analyses revealed that at relevant sampling timepoints, PCR-positive blood samples were detected more frequently and reached higher percentages (up to 100% during fever) than oral and rectal swabs. Moreover, mean Ct values in blood samples collected from animals infected with virulent strains were significantly lower than in oral and rectal swabs, ensuring a higher probability of ASFV detection. High Ct values and occasional shedding in all tested matrices, in the cases of animals infected by an attenuated ASFV-strain, showed that blood sampling may be necessary to confirm the presence of anti-ASFV antibodies in sera. This study showed that during veterinary surveillance, blood sampling (for both PCR and serological analyses) is essential for the accurate diagnosis of ASF and provides the highest probability of detection of the disease.

African swine fever (ASF) is one of the most dangerous hemorrhagic infectious diseases that affect domestic and wild pigs. Currently, neither a vaccine nor effective treatments are available for this disease. As regards the degree of virulence, ASFV strains can be divided into high, moderate, or low virulence. The main detection methods are based on the use of the polymerase chain reaction (PCR). In order to prevent an uncontrolled spread of ASF, new on-site techniques that can enable the identification of an early-stage disease are needed. We have developed a specific immunological SPR-based assay for ASFV antigen detection directly in liquid samples. The developed assay allows us to detect the presence of ASFV at the dose of 10³ HAD₅₀/_mL.

African swine fever (ASF) is a lethal hemorrhagic disease of Suidae, i.e., domestic pigs and wild boars. The disease was introduced to Poland in 2014 and is now present in the wild boar population. Appropriate ASF prevention requires further research for answers to fundamental questions about the importance of vectors in virus transmission, the impact of environmental factors on the presence of ASFV in wild boar habitats, and the role of survivors as potential virus carriers and their part in the potential endemicity of ASF. In order to analyze the changes in the molecular and serological prevalence of ASFV in wild boar population in Poland, real-time PCR and ELISA/IPT tests were conducted. In the analyzed period (2014–2020), most of the ASF-positive wild boars were molecular/virus-positive, however, over the years the percentage and the number of seropositive animals has increased. At the beginning of the epidemic, the disease was limited to a small area of the country. Since then, it has spread to new provinces of Poland. From the beginning and until today, most notifications of ASF-positive wild boars were for carcasses (passive surveillance), however, the number of serologically positive animals is still increasing. Despite the fact that notifications of ASF outbreaks are still being received near the eastern border of Poland, the old ASF area seems to be limited mainly to ASF serologically positive animals, which may indicate the beginning of ASF endemicity in Poland.

Porcine circovirus type 3 (PCV3), a novel circovirus, imposes great burdens on the global pig industry. The penside tests for detecting PCV3 are critical for assessing the epidemiological status and working out disease prevention and control programs due to the unavailability of a commercial vaccine. A one-step molecular assay based on visual loop-mediated isothermal amplification (vLAMP) was developed for simple and rapid detection of PCV3. We compared its sensitivity and specificity with TaqMan quantitative real-time polymerase chain reaction (qPCR) and applied the developed assay in the epidemiological study of (n = 407) pooled swine sera collected from almost the entire mainland China during the years 2017–2018. We also explored the feasibility of the vLAMP assay for detecting raw samples without a prior DNA isolation step to expand its application capability. Results showed that the vLAMP assay could reliably detect the PCV3 cap gene with a detection limit of 10 DNA copies equal to that of the Taqman qPCR assay. In the epidemiological study, the PCV3 positive detection rate for 407 swine pooled sera detected by the vLAMP assay was 37.35% (152/407), whereas it was 39.01% (159/407) for Taqman qPCR. For the detection method without genome extraction, the results kept satisfactory specificity (100%) but displayed lower sensitivity (100% for CT < 32), indicating the direct detection is not sensitive enough to discriminate the samples with low viral loads. The one-step vLAMP is a convenient, rapid, and cost-effective diagnostic for penside detection and will enable the epidemiological surveillance of PCV3, which has widely spread in mainland China.