Infected Pigs Research Articles

Experimental Infections of Pigs with Japanese Encephalitis Virus Genotype 4

The emergence of Japanese encephalitis virus (JEV) in eastern Australia in 2022 caused extensive reproductive disease in pigs and is a threat to public health. Groups of weaned piglets were experimentally infected with the Australian outbreak strain of JEV (genotype 4). All pigs challenged at 5 weeks of age were infected after an intradermal injection of 1 × 105.5 (n = 4) or 1 × 104.5 TCID50/pig (n = 5). Intranasal instillation was less effective at this age, infecting 3/4 pigs with the same higher dose and 1/5 with the lower dose. Intradermal injection using 1 × 105.0 TCID50/pig also infected 9/9 pigs at 11 weeks of age. Infection in all cases was confirmed by qRT-PCR of blood samples, which identified a viremia peak at 3–4 days and detected JEV-specific antibodies as early as 5 days after the challenge. The detection of JEV in oral and nasal swabs and in saliva from chew ropes was less consistent. JEV was detected in the tonsils of 21/22 infected pigs and was isolated from the tonsils of 9/9 pigs sampled 19 days after the challenge at 11 weeks of age. The infected pigs showed no clinical signs other than pyrexia on Days 4–6. Histopathology consistent with JEV infection was evident in the nervous tissues of all but two pigs sampled 28 days after the challenge and was characterized by meningitis, encephalitis and gliosis throughout the brain. Serological studies showed extensive cross-reactivity between JEV and Murray Valley encephalitis virus using blocking ELISAs. However, the determination of limiting-dilution titres allowed for the identification of the infecting virus. This in vivo infection model will be useful in evaluating JEV vaccines and for comparative pathogenesis studies with other JEV genotypes.

High prevalence of porcine cysticercosis in slaughtered pigs in Rwanda: An abattoir survey.

Porcine cysticercosis (PC) is an important public health problem, especially in sub-Saharan Africa, but limited information is available on the prevalence of infection in pigs entering the food chain. Existing diagnostic methods vary in accuracy and efficiency; whole carcass dissection is the most reliable method but is labour-intensive and destroys the carcass so can only be used in a research setting. Serological tests offer lower specificity, while meat inspection and lingual examination lack sensitivity, hampering accurate estimates and the removal of infected pigs from the food chain. Here, we provide the first estimates of PC prevalence in abattoirs in Rwanda. We use whole carcass dissection to determine the diagnostic accuracy of a commercial antigen-ELISA to estimate the true prevalence of infection across Rwanda and identify Taenia species affecting local pigs. We carried out a cross-sectional survey in 6 abattoirs across Rwanda (n = 744 pigs), with whole carcass dissection of a subset of 67 pigs. Cysts were detected in 20/67 (30%) of carcasses, with >1000 cysts in 9/20 (45%) of infected pigs. All cysts were identified as Taenia solium by PCR-RFLP, with no cysts of Taenia hydatigena found. The antigen-ELISA showed a sensitivity of 90% (95% CI: 68-99) and specificity of 85% (95% CI: 72-94), when compared to dissection. Using these estimates, the true prevalence was calculated as 25-43% in two abattoirs in south-west Rwanda, and 2-3% in the rest of the country. Fewer than half of infected pigs were detected by tongue palpation and post-mortem veterinary inspection. Our data indicate a high prevalence of PC in Rwandan abattoirs. Tongue palpation and veterinary inspections, as currently carried out, have little impact in removing cyst-infested pigs from the food chain. Additional interventions are needed, such as proper pig husbandry, treatment and vaccination against cysticercosis, health education, improved sanitation and hygiene, and improved processing and cooking of meat.

Novel Porcine Getah Virus from Diarrheal Piglets in Jiangxi Province, China: Prevalence, Genome Sequence, and Pathogenicity.

Getah virus (GETV) is a mosquito-borne virus belonging to the genus Alphavirus in the family Togaviridae. Its infection poses an increasing threat to animals and public health in China. In this study, an epidemiological survey of GETV on 46 pig farms in Jiangxi Province, China, was performed; GETV isolation and characterization were carried out, including a complete sequence determination and phylogenetic analysis; and pathogenicity of the GETV was experimentally investigated by inoculating newborn piglets with the isolated GETV strain. Epidemiological studies conducted on the organs of infected pigs, aborted piglets, and the blood of aborted sows sampled from pig farms in Jiangxi Province, China, demonstrated that 44 out of the 46 pig farms were positive for GETV, which is a positivity rate of 95.65% (44/46). Of the 411 samples tested, 47.93% (197/411) were found positive for GETV. A GETV strain called GETV-JX-CHN-22 was obtained, which showed stable proliferation in Vero cells. One-step growth curve results showed that the GETV-JX-CHN-22-P7 (passage 7) isolate reached a peak titer of 108.3 TCID50/mL at 24 hpi. An analysis of the whole-genome sequencing results showed that GETV-JX-CHN-22 (prototype) and GETV-JX-CHN-22-P7 shared nucleotide sequence similarities of 95.3% to 99.6% with 73 reference strains of GETV in GenBank. Genetic evolution analysis revealed that GETV-JX-CHN-22 and GETV-JX-CHN-22-P7 belonged to the GIII group, the same group members of most strains were reported in China. Animal inoculation experiments indicated that piglets exhibited typical symptoms and pathological changes of GETV infection after 24 h inoculation, which reproduced the pathogenicity of GETV field strain infections in piglets. To our knowledge, this study is the first report on the detection and isolation of porcine GETV associated with diarrhea from pig farms in Jiangxi Province, China. It is of great importance to study the infection spectrum, transmission mechanism, and public health significance of GETV. The results provide foundations for the genomic and biological (pathogenic) characteristics of the circulating GETV in Jiangxi Province, China.

Single-Cell Antigen Receptor Sequencing in Pigs with Influenza.

Understanding the pulmonary adaptive immune system of pigs is important as respiratory pathogens present a major challenge for swine producers and pigs are increasingly used to model human pulmonary diseases. Single-cell RNA sequencing (scRNAseq) has accelerated the characterization of cellular phenotypes in the pig respiratory tract under both healthy and diseased conditions. However, combining scRNAseq with recovery of paired T cell receptor (TCR) α and β chains as well as B cell receptor (BCR) heavy and light chains to interrogate their repertoires has not to our knowledge been demonstrated for pigs. Here, we developed primers to enrich porcine TCR α and β chains along with BCR κ and λ light chains and IgM, IgA, and IgG heavy chains that are compatible with the 10x Genomics VDJ sequencing protocol. Using these pig-specific assays, we sequenced the T and B cell receptors of cryopreserved lung cells from CD1D -expressing and -deficient pigs after one or two infections with influenza A virus (IAV) to examine whether natural killer T (NKT) cells alter pulmonary TCR and BCR repertoire selection. We also performed paired single-cell RNA and receptor sequencing of FACS-sorted T cells longitudinally sampled from the lungs of IAV-vaccinated and -infected pigs to track clonal expansion in response to IAV exposure. All pigs presented highly diverse repertoires. Pigs re-exposed to influenza antigens from either vaccination or infection exhibited higher numbers of expanded CD4 and CD8 T cell clonotypes with activated phenotypes, suggesting potential IAV reactive T cell populations. Our results demonstrate the utility of high throughput single-cell TCR and BCR sequencing in pigs.

Oropharyngeal swab sampling for PRRSV detection in large-scale pig farms: a convenient and reliable method for mass sampling

BackgroundPorcine reproductive and respiratory syndrome virus (PRRSV) has significant productivity and economic impacts in swine herds. Accurately determining the PRRSV status at the herd level is crucial for producers and veterinarians to implement strategies to control and eliminate the virus from infected herds. This study collected oropharyngeal swabs (OSs), nasal swabs (NSs), oral fluid swabs (OFs), rectal swabs (RSs), and serum samples continuously from PRRSV challenged pigs under experimental conditions and growing pigs under field conditions. Additionally, OSs and serum samples were collected from individual sows from 50 large-scale breeding farms, and the collection of OSs does not require the sows to be restrained. Ct values of PRRSV were detected in all samples using real-time reverse transcriptase-polymerase chain reaction (RT-qPCR).ResultsIn PRRSV challenged pigs, OSs showed a higher PRRSV-positive rate until the end of the observation period. The Ct values of OSs were significantly lower than those of NSs, OFs, and RSs at 2, 8, 12, 14 and 20 days post-challenge (DPC) (P < 0.05). For growing pigs, the positivity rate of PRRSV in OSs was higher than that in other sample types at 30, 70, and 110 days of age. In sows, 24,718 OSs and 6259 serum samples were collected, with PRRSV-positive rate in OSs (9.4%) being significantly higher than in serum (4.1%) (P < 0.05). However, the Ct values of PRRSV RNA in serum were significantly lower than those in OSs (P < 0.001).ConclusionsThe OSs sample type yielded higher PRRSV-positive rates for longer periods compared to NSs, RSs, OFs and serum samples for PRRSV detection in infected pigs. Therefore, OSs has a good potential to be a convenient, practical, and reliable sample type for implementing mass sampling and testing of PRRSV in large-scale pig farms.

Cold atmospheric plasma as a promising tool in treatment of Trichophyton rubrum-induced skin infection in a guinea pig model of experimental dermatophytosis

The emergence of high-resistance strains to known antifungal drugs has highlighted the urgency of developing novel therapies for chronic dermatophytosis as a global health problem. An experimental dermatophytosis model in guinea pigs was developed to investigate the in vivo wound healing effects of cold atmospheric plasma (CAP) on T. rubrum skin invasion. Guinea pigs were experimentally infected with T. rubrum and wound healing was evaluated at 1, 4, 8 and 12 days post infection in the CAP-treated, terbinafine-treated and non-treated controls. Our results showed that CAP strongly inhibited the fungal virulence in vitro in culture media and in vivo on the skin lesions of experimentally infected guinea pigs even more efficient than that of terbinafine, resulting in complete wound healing at 8 days post infection. These results indicate that CAP would be considered as a promising tool comparable to conventional chemical therapies, for the treatment of drug-resistant chronic dermatophytosis caused by T. rubrum.

Strategic nucleic acid detection approaches for diagnosing African swine fever (ASF): navigating disease dynamics.

African swine fever (ASF) is a devastating disease caused by African swine fever virus (ASFV) and leads to significant economic losses in the pig farming industry. Given the absence of an effective vaccine or treatment, the mortality rate of ASF is alarmingly close to 100%. Consequently, the ability to rapidly and accurately detect ASFV on site and promptly identify infected pigs is critical for controlling the spread of this pandemic. The dynamics of the ASF virus load and antibody response necessitate the adoption of various detection strategies at different stages of infection, a topic that has received limited attention to date. This review offers detailed guidance for choosing appropriate ASF diagnostic techniques tailored to the clinical manifestations observed from the acute to chronic phases, including asymptomatic cases. We comprehensively summarize and evaluate the latest advancements in ASFV detection methods, such as CRISPR-based diagnostics, biosensors, and microfluidics. Additionally, we address the challenges of false negatives or positives due to ASF variants or the use of injected live attenuated vaccines. This review provides an exhaustive list of diagnostic tests suitable for detecting each stage of symptoms and potential target genes for developing new detection methods. In conclusion, we highlight the current challenges and future directions in ASFV detection, underscoring the need for continued research and innovation in this field.

Monitoring of Respiratory Disease Patterns in a Multimicrobially Infected Pig Population Using Artificial Intelligence and Aggregate Samples

A 24/7 AI sound-based coughing monitoring system was applied in combination with oral fluids (OFs) and bioaerosol (AS)-based screening for respiratory pathogens in a conventional pig nursery. The objective was to assess the additional value of the AI to identify disease patterns in association with molecular diagnostics to gain information on the etiology of respiratory distress in a multimicrobially infected pig population. Respiratory distress was measured 24/7 by the AI and compared to human observations. Screening for swine influenza A virus (swIAV), porcine reproductive and respiratory disease virus (PRRSV), Mycoplasma (M.) hyopneumoniae, Actinobacillus (A.) pleuropneumoniae, and porcine circovirus 2 (PCV2) was conducted using qPCR. Except for M. hyopneumoniae, all of the investigated pathogens were detected within the study period. High swIAV-RNA loads in OFs and AS were significantly associated with a decrease in respiratory health, expressed by a respiratory health score calculated by the AI The odds of detecting PRRSV or A. pleuropneumoniae were significantly higher for OFs compared to AS. qPCR examinations of OFs revealed significantly lower Ct-values for swIAV and A. pleuropneumoniae compared to AS. In addition to acting as an early warning system, AI gained respiratory health data combined with laboratory diagnostics, can indicate the etiology of respiratory distress.

Miniature pigs as the intermediate host for Taenia asiatica

Taenia asiatica, utilizing pigs as an intermediate host, degenerates and/or calcifies within a few months after infection in pigs, whereas Taenia solium, also using pigs as an intermediate host, can develop into a mature metacestode within a couple of months and can survive for prolong periods in pigs. This raises the question of whether pigs are suitable intermediate hosts for T. asiatica. The host-parasite relationships between T. asiatica and pig strains, such as infection rates and development of metacestodes, have been reported in previous studies: however, little is known about the pathological changes that occur in T. asiatica metacestodes in pigs. Therefore, in the present study, the pathological changes in T. asiatica within 30 days of infection were observed using CLAWN miniature pigs as model animals. Metacestodes were observed on the diaphragmatic surface and throughout the parenchyma of the pig liver 9 days after infection; however, these metacestodes were surrounded by eosinophilic abscesses, and some had already begun to degenerate. By day 20 and 30 post-infection, metacestodes were surrounded by eosinophilic abscesses and had completely degenerated without forming a scolex. These results indicate that although T. asiatica infected miniature pigs, the metacestodes degenerated owing to strong immune responses from the pigs. Therefore, the CLAWN miniature pig are not a suitable intermediate host for T. asiatica. The possible reasons why T. asiatica metacestodes were degenerated and the potential roles of pigs in transmitting the parasite to humans in T. asiatica-endemic regions are discussed in this study. Additionally, data debating whether pigs are suitable intermediate hosts for T. asiatica are provided.

Development of a Formula for Calculating the Probability of the Spread of African Swine Fever

Robust epidemiological knowledge and predictive modelling tools are needed to address challenging objectives forecasting epidemics. Often, multiple modelling approaches can be used during an epidemic to support effective decision making in a timely manner. A formula has been developed for calculating the probability of spreading african swine fever from infected animals of a threatened pig farm to other farms. The formula allows you to calculate the probability of an outbreak of infection for pigs of each of the pig farms located in the analyzed area. This takes into account the possible ways of spreading the pathogen in the presence of mechanisms and factors of transmission of african swine fever in real time.

Prevalence of Gastrointestinal Parasites in Pigs in Bali

This study aimed to identify gastrointestinal parasites in pigs in Bali. A total of 117 pig feces samples were collected in Buleleng Regency (n = 67) and Jembrana (n = 50). Samples were examined microscopically using native, sedimentation, and floating methods. The results reported the prevalence of gastrointestinal parasites infecting pigs in Bali was 94.8% (111/117) infected with protozoa, namely Eimeria sp. (90.5%), Entamoeba sp. (26.4%), Isospora suis (6.8%), and Balantidium sp. (5.1%), while 99.1% (116/117) were infected with helminths, namely Trichuris suis (71.7%), Strongyloides sp. (64.9%), Ascaris suum (49.5%), Oesophagostomum sp. (6.1%), Macracanthorhyncus sp. (2.5%), and Hyostrongylus sp. (0.8%). Based on the tree regression analysis reported that the rearing system was related to the degree of gastrointestinal parasite infection in pigs in Bali.

Machine Learning-based Prediction of African Swine Fever (ASF) in Pigs

African Swine Fever (ASF) is a contiguous viral disease of the pig with serious economic threats to the pork industry. Early identification of ASF infection is important to support sustainable developments in the ASF industry. There is also a need for a solution to identify the ASF infection as early as possible based on apparent symptoms of ASF to screen the infected animals, that are not targeted in the existing literature. Many machine learning (ML) solutions have been proposed in recent years for the prediction and identification of human, animal, and plant diseases. To deal with ASF in pigs ML-assisted model is proposed for the early identification of ASF infection without medical diagnosis and expert opinion. The data regarding apparent symptoms are collected from Chinese small pig farms. The loss of appetite, weakness, diarrhea, vomiting, coughing, skin redness, and breathing difficulty levels are taken as major apparent symptoms of ASF infection. Moreover, different ML models are also evaluated for their performance in the prediction of ASF infection based on selected apparent symptoms of ASF infection. In this regard, Support Vector Machine (SVM), K-Nearest Neighbor (k-NN), Decision Tree (DT), Random Forests (RF), and Gaussian Naïve Bayes ML models are evaluated for ASF infection prediction. The implementation of the proposed solution reveals that the GNB model is more accurate as compared to the other evaluated models for the identification of ASF infection from the apparent ASF symptoms in infected pig animals, with 94.31\% accuracy. The proposed solution would be very effective in the early screening of ASF-infected pig animals without medical diagnosis and expert judgment.

African swine fever virus RNA polymerase subunits C315R and H359L inhibition host translation by activating the PKR-eIF2a pathway and suppression inflammatory responses.

ASFV C315R is homologous to the transcription factor TFIIB of large unclassified DNA viruses, and H359L is identical to the subunit 3 (RPB3) of eukaryotic RNA polymerase II. The C315R and H359L may play an important role in ASFV replication and transcription. Here, we evaluated the biological function of the C315R and H359L genes during virus replication in vitro and during infection in pigs. Results showed that C315R and H359L are highly conserved among ASFV genotype II strains; quantitative PCR (qPCR) and western blotting analyses revealed that C315R and H359L are early transcribed genes prior to viral DNA replication, but their protein expression is delayed. The immunofluorescence and western blotting analysis revealed that both proteins localized in the cell cytoplasm and nucleus at 24 h post infection, however, pH359L was mainly detected in the cell cytoplasm. Furthermore, overexpression of pH359L in MA104 cells significantly increased viral titer, RNA transcription levels, and viral protein expression levels, while overexpression of pC315R slightly enhanced ASFV replication. In contrast, siRNA targeting ASFV-H359L or C315R reduced replication efficiency in porcine macrophage culture compared to the parent ASFV-CN/SC/2019, demonstrating that C315R and H359L genes are necessary for ASFV replication. Finally, the functional role of C315R or H359L on PKR and eIF2α phosphorylation status and SG formation, as well as cytokine production were evaluated. These studies demonstrated that C315R and H359L are involved in virus replication processes in swine and play important roles in ASFV replication.

The infectious capacity of Enterococcus faecalis, Staphylococcus aureus, and Staphylococcus saprophyticus in a porcine model of urinary tract infection.

The purpose of this study was to establish a porcine model of urinary tract infection (UTI) with gram-positive uropathogens. Ten female domestic pigs were experimentally inoculated with human UTI isolates of Enterococcus faecalis (n = 3), Staphylococcus saprophyticus (n = 3), or Staphylococcus aureus (n = 4) and followed with regular urine samples. Bladders and kidneys were aseptically removed at termination (5-7 days post infection) and assessed by gross pathology and bacterial enumeration. Enterococcus faecalis (n = 3 of 3) and S. aureus (n = 2 of 4) successfully colonized the pig bladders. Inoculation with S. saprophyticus never resulted in detectable bacteriuria. All infected pigs had cleared the infection spontaneously before termination. Surprisingly, three (of four) pigs inoculated with S. aureus led to spontaneous infection with opportunistic pathogens. Also, one pig colonized with E. faecalis resulted in spontaneous infection with E. coli. In conlusion, the pig supports experimental UTI with E. faecalis for up to 24 h but not prolonged infection. S. aureus and S. saprophyticus fails to cause UTI in pigs and other animals should be considered for studying these pathogens.

277 Estimating the potential effect of Mycoplasma hyopneumoniae infection on swine sustainability

Abstract Mycoplasma hyopneumoniae is the primary causative agent of enzootic pneumonia, one of the most common bacterial pathogens affecting pigs and the main contributor to respiratory comorbidities. Infection with M. hyopneumoniae, commonly observed in growing pigs, results in decreased feed intake and an increase in the number of days to reach market weight. Based on extended days to market, pigs infected with M. hyopneumoniae will have a greater life cycle carbon emissions and water usage than that of non-infected pigs. However, the magnitude of additional carbon footprint and water use in pigs infected with M. hyopneumoniae has never been calculated. Therefore, the objective of this study was to estimate the potential variation in carbon emissions and water footprint generated by M. hyopneumoniae infected pigs. This study was conducted using data from previous publications on M. hyopneumoniae infected pigs in experimental and commercial conditions. The carbon footprint and water usage of pork production was obtained from the literature and was used as a baseline (3,470 kg of CO2 eq and 1,678 m3 water eq; both per 1,000 kg of pork carcass weight). The change in average daily gain was estimated and additional days on feed to reach market weight were used to calculate potential carbon and water impact for pigs infected with M. hyopneumoniae. The estimated carbon emissions and water usage of M. hyopneumoniae infected pigs increased in a range of 84.69 to 142.93 kg of CO2 eq/1,000 kg of pork carcass weight and 40.95 to 69.12 m3 eq/1,000 kg of pork carcass weight respectively, compared with the carbon emissions of non-infected pigs (Table 1). Results of this study showed an increased carbon footprint for M. hyopneumoniae infected pigs by 2 to 4% and water usage increased by 2.5 to 4.1% suggesting that the sustainability of pork production was negatively affected by this bacterial infection. Previous literature on the impact of controlling vaccine-preventable diseases has shown similar results for other swine respiratory pathogens. In addition, these data only included M. hyopneumoniae infected pigs, thus the effect of respiratory co-infections was not estimated and the impact on sustainability metrics may be greater than currently calculated. The application of sustainable practices in animal production, including disease prevention, is key to ensuring a secure food supply for future generations. The carbon and water footprints of swine production are measurements of sustainability, with average daily gain being an important factor.

40 The gut microbiota modifies host-parasite interactions

Abstract It is well documented that parasitic infections induce a profound change in the structure and function of host gut microbiota, likely due to infection-associated perturbations in the gut microenvironment. However, the mechanisms remain largely unknown. Here we aim to understand how the gut microbiota is modified by host-parasite relationships or vice versa using an integrated multi-omics analysis in a swine-Ascaris infection model. Female pigs (n = 30; 6 to 8 mo of age) were randomly divided into three groups (n = 10 per group). One group served as normal uninfected controls (NU); the remaining 20 pigs were inoculated per os with ~10,000 infective A. suum eggs; and the infection was allowed to progress for 35 d post-inoculation (dpi). At 21 dpi, one of the infected groups (IP) was treated with a single daily dose of an anthelmintic drug, Panacur, for three consecutive days while the other infected pigs remained untreated (IU). At necropsy, intestine tissue, serum and fecal samples were collected for untargeted metabolome analysis using UPLC-MS/MS and the fecal microbiota was characterized using full-length 16S rRNA gene-based sequencing with DADA2. Fecal and serum metabolites were categorized for their origin using MetOrigin. An integrated multi-omics analysis was performed using DIABLO algorithms and NetCoMi networking tools. Our results showed that A. suum worms were well developed in pigs from the IU group, which harbored a significantly reduced microbiota alpha diversity (Simpson, P &amp;lt; 0.005) compared with NU. The infection altered the abundance of at least 17 bacterial species/strains, including multiple butyrate-producing Clostridium spp., such as C. butyricum. The infection also dysregulated 51 fecal metabolites, including microbiota-derived metabolites such as glutaric acid and p-Cresol sulfate, and succinate of mixed origin. Moreover, the anthelmintic treatment was efficacious and eliminated all worms from the gut. Nevertheless, 11 pathways of both host and microbiota origin were significantly enriched in the gut of pigs from the IP group, including peptidoglycan biosynthesis, histidine metabolism (in both feces and serum), and primary bile acid biosynthesis, suggesting the infection-induced alterations may not be transient. In conclusion, the host microbiota modified swine-Ascaris interactions via three different mechanisms. First, microbiota-derived metabolites directly regulate host gene expression, which in turn affects host physiology and immune responses. Second, plasticity of the gut microbiota allows the exploitation of the niche differentiated upon infection, resulting in blossom of certain strains in the gut of post-treated animals. Lastly, the host microbiota is likely one of the key determinants of parasite gut microbiota, indirectly exerting its effect on parasite physiology and nutrition. Further studies aiming to understand reciprocal yet complex relations between the gut microbiota, the host, and parasites (including parasite gut microbiota) will be conducive to the design of next-generation functional anthelmintics.

Retrospective Analyses of Porcine Circovirus Type 3 (PCV-3) in Switzerland.

Porcine circovirus 3 (PCV-3) has emerged as a significant pathogen affecting global swine populations, yet its epidemiology and clinical implications remain incompletely understood. This retrospective study aimed to investigate the prevalence and histopathological features of PCV-3 infection in pigs from Switzerland, focusing on archival cases of suckling and weaner piglets presenting with suggestive lesions. An in-house qPCR assay was developed for detecting PCV-3 in frozen and formalin-fixed paraffin-embedded tissues, enhancing the national diagnostic capabilities. Histopathological reassessment identified PCV-3 systemic disease (PCV-3-SD) compatible lesions in 19 (6%) of archival cases, with 47% testing positive by qPCR across various organs. Notably, vascular lesions predominated, particularly in mesenteric arteries, heart, and kidneys. The study confirms the presence of PCV-3 in Switzerland since at least 2020, marking the first documented cases within the Swiss swine population. Despite challenges in in situ hybridization validation due to prolonged formalin fixation, the findings indicate viral systemic dissemination. These results contribute to the understanding of PCV-3 epidemiology in Swiss pigs, emphasizing the need for continued surveillance and further research on its clinical implications and interaction with host factors. Our study underscores the utility and limitations of molecular techniques in confirming PCV-3 infections.

Virus Shedding and Diarrhea: A Review of Human Norovirus Genogroup II Infection in Gnotobiotic Pigs.

For nearly twenty years, gnotobiotic (Gn) pigs have been used as a model of human norovirus (HuNoV) infection and disease. Unique in their ability to develop diarrhea and shed virus post oral challenge, Gn pigs have since been used to evaluate the infectivity of several genogroup II HuNoV strains. Nearly all major pandemic GII.4 variants have been tested in Gn pigs, with varying rates of infectivity. Some induce an asymptomatic state despite being shed in large quantities in stool, and others induce high incidence of both diarrhea and virus shedding. Non-GII.4 strains, including GII.12 and GII.6, have also been evaluated in Gn pigs. Again, rates of diarrhea and virus shedding tend to vary between studies. Several factors may influence these findings, including age, dosage, biological host factors, or bacterial presence. The impact of these factors is nuanced and requires further evaluation to elucidate the exact mechanisms behind increases or decreases in infection rates. Regardless, the value of Gn pig models in HuNoV research cannot be understated, and the model will surely continue to contribute to the field in years to come.

Near zero background noise photoelectrochemical sensor based on sensitized signal probe CdS QDs-Dox intercalating double-stranded DNA for PEDV detection

The highly sensitive detection method for porcine epidemic diarrhea virus (PEDV) is crucial for promptly identify infected pigs and effectively control the spread of the virus. In this study, the sensitization enhancement of organic photoactive material was combined with near zero background noise strategy for PEDV sensitive detection. A novel sensitized signal probe CdS quantum dots-doxycycline complex (CdS QDs-Dox) was prepared serving as a photoelectrochemical (PEC) probe embedded in dsDNA. Subsequently, a thiol-modified upstream inner primer (SH-FIP) was immobilized on the surface of electrode modified with gold nanoparticles (Au NPs) via Au–S bonding, enabling the loop-mediated isothermal amplification (LAMP) of PEDV on the electrode surface. The PEC probe (CdS QDs-Dox) embedded in the amplified dsDNA groove showed an increasing photocurrent signal with the rise of PEDV concentration, establishing a near-zero background LAMP-PEC sensing platform for PEDV detection. Under optimized conditions, the photocurrent intensity of this platform exhibited a good linear relationship with PEDV concentrations ranging from 0.0005 pg/μL to 10 pg/μL, achieving a detection limit as low as 0.17 fg/μL. This platform demonstrates outstanding specificity and sensitivity, thereby enabling precise quantitative detection of diverse pathogens.

Japanese encephalitis in swine in San Jose, Tarlac, Philippines

ObjectivesA systematic review of multidisciplinary studies on Japanese encephalitis (JE) in the Philippines indicated that endemic foci may be found in all 17 administrative regions in the country. MethodsTo establish the etiology of the disease, virus detection and seroprevalence surveys in 198 pigs were conducted in 2010–2011 in four barangays (villages) in the Municipality of San Jose, Tarlac. Prior to the present study, JE virus genotype III (JEV GIII) was recovered from the mosquito, Culex tritaeniorhynchus, in the same municipality where backyard hog-raising and wet rice cultivation were common practices among households located within 1 km radius from the paddies. ResultsJEV GIII was detected from serum and nasal swabs from pigs, 3 to 5-month-old, from barangays Pao, Moriones, and Villa Aglipay. Immunoglobulin (Ig) M and IgG were measured by enzyme-linked immunosorbent assay in pigs < 4 to > 8 months old, with an overall total of 17.2 % and 62.1 %, respectively. The presence of these antibodies in all pigs during four observation periods indicated year-round transmission starting with the rainy season, which encompasses the months of July and September 2010. IgM represented new infections. IgG increased correspondingly with age with repeated infections in older pigs. IgG levels remained high in all barangays. The number of households with any one of the markers: IgM, IgG, reverse transcription-polymerase chain reaction averaged out at 82.5 %, reflecting as it were, vulnerability to JE in barangays where all 198 pigs were examined. This report contributes to knowledge on JE, whereby incidence in humans may be linked to its epizootic spillover from pigs. ConclusionsThe study has shown that four barangays, representing a rice-farming community, supported the enzootic cycle of JE in swine, with mosquitoes previously found to be infected with JEV GIII in San Jose. Thus, infected pigs, rainfall, and proximity of human habitation to breeding sites of vector mosquitoes constituted the risk factors for JE, as it were in other endemic countries in Asia. The finding of viral RNA in nasal swabs suggests the possibility of direct transmission among pigs via the oronasal route. From the standpoint of public health, JE immunization of children and periodic surveillance of swine are recommended.