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African swine fever (ASF), caused by ASF virus (ASFV), represents one of the most economically important viral infectious diseases in swine industry worldwide. So far there is no vaccine or antiviral drug for controlling ASF pandemics. In the present study, we assessed inhibition of six nucleoside analogues against ASFV replication in ex vivo primary porcine alveolar macrophages (PAMs), including the first approved antiviral drug idoxuridine. Our results showed that, out of the assessed six compounds, 5-Bromo-2′-Deoxyuridine (5-BrdU, an analog of idoxuridine), exhibited the strongest inhibition on the replication of ASFV in PAMs with a 50% inhibitory concentration (IC 50) value of 2.9 μM and a low cytotoxicity (CC 50 > 270 μM). Moreover, we showed that 5-BrdU interferes with ASFV DNA replication by incorporating into viral replicating DNA molecules as a competitive substrate for deoxythymidine, ultimately inhibiting the formation of ASFV viral factories. Altogether, our findings suggest that 5-BrdU could serve as a promising therapeutic agent for combating ASFV infection. [Display omitted] • First to show 5-BrdU significantly inhibits ASFV proliferation. • Unveils 5-BrdU's disruption of ASFV DNA replication and viral assembly. • Highlights 5-BrdU as a potential ASF therapeutic. [ABSTRACT FROM AUTHOR]

C. Earthworms Porcine pulmonary metastrongylosis is caused by 3 helminth species: I Metastrongylus apri, M. pudendotectus i , and I M. salmi i . Infected pigs may have slower growth rates, and severe infections can cause pneumonia. Image Challenge in Veterinary Pathology, Answers: Swine Diseases. [Extracted from the article]

Live pig trade patterns, drivers and characteristics, particularly in backyard predominant systems, remain largely unexplored despite their important contribution to the spread of infectious diseases in the swine industry. A better understanding of the pig trade dynamics can inform the implementation of risk-based and more cost-effective prevention and control programs for swine diseases. In this study, a semi-structured questionnaire elaborated by FAO and implemented to 487 farmers was used to collect data regarding basic characteristics about pig demographics and live-pig trade among villages in the country of Georgia, where very scarce information is available. Social network analysis and exponential random graph models were used to better understand the structure, contact patterns and main drivers for pig trade in the country. Results indicate relatively infrequent (a total of 599 shipments in one year) and geographically localized (median Euclidean distance between shipments = 6.08 km; IQR = 0-13.88 km) pig movements in the studied regions. The main factors contributing to live-pig trade movements among villages were being from the same region (i.e., local trade), usage of a middleman or a live animal market to trade live pigs by at least one farmer in the village, and having a large number of pig farmers in the village. The identified villages' characteristics and structural network properties could be used to inform the design of more cost-effective surveillance systems in a country which pig industry was recently devastated by African swine fever epidemics and where backyard production systems are predominant.

Vertebrate scavengers provide essential ecosystem services such as accelerating carrion decomposition by consuming carcasses, exposing tissues to microbial and invertebrate decomposers, and recycling nutrients back into the ecosystem. Some scavengers do not consume carcasses on site but rather scatter their remains in the surroundings, which might have important implications for nutrient transport, forensic investigations and the spread of diseases such as African Swine Fever. However, only a few studies have investigated and measured the scatter distances. Using wild boar (Sus scrofa) carcasses and limbs, we monitored scavenging behavior and measured scatter distances of mammals. We placed 20 carcasses (up to 25 kg) and 21 separate limbs equipped with very high frequency (VHF) transmitters and monitored scavenger activity using camera traps in a mountainous region in southeast Germany. Except for one carcass, all other carcasses and limbs were scattered. We measured 72 scatter distances (of 89 scattering events; mean = 232 m, maximum = 1250 m), of which 75% were dispersed up to 407 m. Scavengers moved scattered pieces into denser vegetation compared to the half-open vegetation at provisioning sites. Red foxes (Vulpes vulpes) were the most common scavenger species, contributing to 72 scattering events (58 measured scatter distances). Our results provide evidence of scatter distances farther than previously assumed and have far-reaching implications for disease management or forensic investigations, as the broader surroundings of carcasses must be included in search efforts to remove infectious material or relevant body parts for forensic analysis. • Wild boar carcasses are frequently dispersed by scavengers, primarily foxes. • Carcasses are dispersed over 400 m in 75% of cases, with a maximum dispersal of 1.2 km. • Scavengers scatter carcasses into denser vegetation compared to provisioning sites. • Carcass search must include broader surroundings in disease management or forensics. [ABSTRACT FROM AUTHOR]

• Three recombinant PEDVs with abolished glycosylation sites in RBD of spike protein were successfully constructed. • Removal of the glycosylation sites in RBD of spike protein does not influence the pathogenicity of PEDV AH2012/12. • RBD glycosylation in spike protein could attenuate the immunogenicity of PEDV AH2012/12. Porcine epidemic diarrhea (PED) is a highly contagious swine intestinal disease caused by PED virus (PEDV). Vaccination is a promising strategy to prevent and control PED. Previous studies have confirmed that glycosylation could regulate the immunogenicity of viral antigens. In this study, we constructed three recombinant PEDVs which removed the glycosylation sites in RBD. Viral infection assays revealed that similar replication characteristics between the recombinant viruses and parental PEDV. Although animal challenging study demonstrated that the glycosylation sites in RBD do not affect the pathogenicity of PEDV, we found that removing the glycosylation sites on the RBD regions could promote the IgG and neutralization titer in vivo , suggesting deglycosylation in RBD could enhance the immunogenicity of PEDV. These findings demonstrated that removal of the glycosylation sites in RBD is a promising method to develop PEDV vaccines. [ABSTRACT FROM AUTHOR]

Porcine reproductive and respiratory syndrome (PRRS) caused by the PRRS virus (PRRSV) is one of the most severe swine diseases causing great economic losses for the international swine industry. Non-structural protein 4 (NSP4) is critical to the life cycle of PRRSV and contains dominant B cell epitopes. This study prepared a monoclonal antibody against Nsp4, and 2D11, which contained the sequence 138KQGGGIVTRPSGQFCN153, was confirmed as the epitope. A 2D11-based double antibody sandwich enzyme-linked immunosorbent assay (dasELISA) was next developed with a cut value of 0.1987. A total of 1354 pig serum samples were detected by dasELISA and compared to a commercial ELISA kit (N-coated iELISA), resulting in a positive coincidence rate of 98.8% and negative coincidence rate of 96.9%. A total of 119 sera were positive by dasELISA while negative by iELISA. Higher positive rates by dasELISA were found in pig farms where PRRSV antibody levels varied widely. These results indicated that the dasELISA was a useful tool to detect PRRSV antibody in clinical samples. • A monoclonal antibody (2D11) to PRRSV NSP4 was prepared. • 138KQGGGIVTRPSGQFCN15 was identified as a dominant epitope. • A dasELISA based on 2D11 was developed. • The developed dasELISA was an effective tool for clinical samples. [ABSTRACT FROM AUTHOR]

porcine reproductive and respiratory syndrome (PRRS), caused by porcine reproductive and respiratory syndrome virus (PRRSV) infection, is an important swine infectious disease that causes substantial losses worldwide each year. PRRSV is a positive-sense single-stranded RNA virus that is highly susceptible to mutation and recombination, making vaccine and drug research for the disease extremely difficult. In this study, the binding of PRRSV nsp2 to HSP71 protein was detected by using the IP/MS technique. And the inhibitory effect of HSP71 on nsp2 antagonistic activity was validated by measuring NF-kB luciferase reporter. According to stress from inhibitory effects, the amino acid variation profile of PRRSV nsp2 under HSP71 stress was further analyzed using second-generation sequencing. Surprisingly, the results indicated that HSP71 pressure limits the random mutations of PRRSV nsp2 and maintains the dominant PRRSV strain within the population. Mutant strain showed weaker antagonistic activity and replication capability in cell. These results imply the binding of HSP71 with PRRSV nsp2 may lead to maintain the stability of highly virulent strains of PRRSV. • Hsp71 binds and inhibits PRRSV nsp2. • hsp71 binding contributes to the stabilization of PRRSV nsp2. • PRRSV nsp2 is prone to random mutations in normal cells. [ABSTRACT FROM AUTHOR]

Respiratory diseases due to viral or bacterial agents, either alone or in combination, cause substantial economic burdens to the swine industry worldwide. Rapid and reliable detection of causal pathogens is crucial for effective epidemiological surveillance and disease management. This research aimed to employ the multiplex ligation-dependent probe amplification (MLPA) assay for simultaneous detection of seven distinct pathogens causing respiratory problems in swine, porcine reproductive and respiratory syndrome virus (PRRSV), swine influenza virus (SIV), porcine respiratory coronavirus (PRCV), porcine circovirus type 2 (PCV2), Pasteurella multocida , Actinobacillus pleuropneumoniae , and Glässerella parasuis. The results indicated no probe cross-reactivity among the seven target agents with other swine pathogens. The detection limits ranged from 5 to 34 copies per assay for the target organisms. The MLPA assay was evaluated with 88 samples and compared to real-time or multiplex PCR for the target pathogens. The MLPA assay demonstrated high relative test sensitivities (100 %) and reasonable to good relative specificities at 62.5 %, 95.1 %, 86.8 %, and 97.6 % for PRRSV, P. multocida , G. parasuis , and PCV2, respectively, relative to comparator PCR assays. In 71 samples where MLPA and comparator PCR assays matched exactly, infections were detected in 64 samples (90.1 %), with PRRSV being the most commonly found virus and 50.7 % of the samples showing co-infection with two to five of the pathogens. This approach serves as a valuable tool for conducting differential diagnoses and epidemiological investigations of pathogen prevalence within swine populations. • An MLPA method was developed to detect seven swine pathogens simultaneously. • PRRSV, PCV2, P. multocida and G. parasuis were detected in nasal swabs. • SIV, porcine respiratory coronavirus and A. pleuropneumoniae were also targeted. • MLPA assay is rapid for specific detection of multiple pathogens in pigs. • The assay has value in epidemiological surveillance of swine diseases. [ABSTRACT FROM AUTHOR]

Senecavirus A (SVA) is a newly identified picornavirus associated with swine vesicular disease and neonatal mortality. The development of an SVA incorporating an exogenous reporter gene provides a powerful tool for viral research. In this study, we successfully constructed a recombinant SVA expressing Gaussia Luciferase (Gluc), termed rSVA-Gluc. The growth kinetics of rSVA-Gluc in BHK-21 cells were found to be comparable to those of the parental virus, and Gluc activity paralleled the virus growth curve. Genetic analysis revealed stable inheritance of the inserted reporter protein genes for at least six generations. We evaluated the utility of rSVA-Gluc in antiviral drug screening, and the results highlighted its potential as an effective tool for such purposes against SVA. The data that support the findings of this study are available on request from the corresponding author. • Generation and recovery of recombinant SVA expressing Gluc. • The recombinant virus exhibits proliferation characteristics on BHK-21 cells similar to the parental virus. • The recombinant virus rSVA-Gluc serves as an effective tool for antiviral drug screening. [ABSTRACT FROM AUTHOR]

African swine fever virus (ASFV) is the etiological agent of African swine fever (ASF), a disease of domestic and wild swine that has spread throughout a large geographical area including Central Europe, East and Southeast Asia, and Southern Africa. Typically, the clinical presentation of the disease in affected swine heavily depends on the virulence of the ASFV strain. Very recently, ASFV was detected in the Dominican Republic (DR) and Haiti, constituting the first diagnosis of ASFV in more than 40 years in the Western hemisphere. In this report, the clinical presentation of the disease in domestic pigs inoculated with an ASFV field strain isolated from samples collected in the DR (ASFV-DR21) was observed. Two groups of domestic pigs were inoculated either intramuscularly (IM) or oronasally (ON) with ASFV-DR21 (104 hemadsorbing dose-50% (HAD50)). A group of naïve pigs (designated as the contact group) was co-housed with the ASFV-DR21 IM-inoculated animals to evaluate ASFV transmission and disease manifestation. Animals inoculated IM with ASFV-DR21 developed an acute disease leading to humane euthanasia at approximately day 7 post-inoculation (pi). Interestingly, animals inoculated via the ON route with ASFV-DR21 developed a heterogeneous pattern of disease kinetics. One animal developed an acute form of the disease and was euthanized on day 7 pi, another animal experienced a protracted presentation of the disease with euthanasia by day 16 pi, and the remaining two animals presented a milder form of the disease, surviving through the 28-day observational period. The contact animals also presented with a heterogenous presentation of the disease. Three of the animals presented protracted but severe forms of the disease being euthanized at days 14, 15 and 21 pi. The other two animals presented with a milder form of the disease, surviving the entire observational period. In general, virus titers in the blood of animals in all study groups closely followed the clinical presentation of the disease, both in length and extent. Importantly, all animals presenting with a prolonged form of the disease, as well as those surviving throughout the observational period, developed a strong ASFV-specific antibody response. These results suggest that ASFV-DR21, unless inoculated parenterally, produces a spectrum of clinical disease, with some animals experiencing an acute fatal form while others presented with a mild transient disease accompanied by the induction of a strong antibody response. At the time of publication, this is the first report characterizing the virulent phenotype of an ASFV field strain isolated from samples collected in the DR during the 2021 outbreak and provides information that may be used in developing epidemiological management measures to control ASF on the island of Hispaniola. [ABSTRACT FROM AUTHOR]

RNA viruses, such as foot-and-mouth disease virus (FMDV), have error-prone replication resulting in the continuous emergence of new viral strains capable of evading current vaccine coverage. Vaccine formulations must be regularly updated, which is both costly and technically challenging for many vaccine platforms. In this report, we describe a plasmid-based virus-like particle (VLP) production platform utilizing transiently transfected mammalian cell cultures that combines both the rapid response adaptability of nucleic-acid-based vaccines with the ability to produce intact capsid epitopes required for immunity. Formulated vaccines which employed this platform conferred complete protection from clinical foot-and-mouth disease in both swine and cattle. This novel platform can be quickly adapted to new viral strains and serotypes through targeted exchanges of only the FMDV capsid polypeptide nucleic acid sequences, from which processed structural capsid proteins are derived. This platform obviates the need for high biocontainment manufacturing facilities to produce inactivated whole-virus vaccines from infected mammalian cell cultures, which requires upstream expansion and downstream concentration of large quantities of live virulent viruses. [ABSTRACT FROM AUTHOR]

Porcine respirovirus 1 (PRV1) is widely spread in many countries. In this study, we isolated an emgerging PRV1 strain (KS17-258) from a US swine farm. A full-length genome sequence of the virus was obtained, and the mRNA editing mechanism utilized for the expression of V/W proteins by P gene was confirmed. The virus shares 91.3–98% nucleotide sequence identity with the other PRV1 genomes reported previously. Phylogenetic analysis showed that KS17-258 forms a clade with the other US isolates. Infectious clone of the KS17-258 isolate was constructed, which was further explored as a viral vector to express enhanced green fluorescent protein (EGFP). The expression cassette of EGFP in the recombinant virus remained stable for 10 passages in cell culture. The availability of PRV1 infectious clone provides an important tool for study the basic PRV1 replication mechanisms. It also provides a novel platform for potential development of vectored vaccines against swine diseases. • An emerging porcine respirovirus 1 (PRV1) was isolated and characterized in vitro. • The first swine paramyxovirus reverse genetic system has established. • PRV1 infectious clone can be used as a viral backbone to stably express a foreign antigen. [ABSTRACT FROM AUTHOR]

Foot-and-mouth disease virus (FMDV) is a picornavirus that produces a highly transmissible vesicular disease that can devastate meat and dairy production to such an extent that FMDV-free countries commit significant economic resources to maintain their FMDV-free status. Senecavirus A (SVA), also a picornavirus, causes vesicular disease in swine that is indistinguishable from FMDV. Since 2015, SVA outbreaks have been reported around the world requiring FMDV-free countries to investigate these cases to rule out FMDV. Understanding the pathogenesis of the SVA and its ability to transmit to naïve populations is critical to formulating control and prevention measures, which could reduce FMDV investigations. The primary objective of this study was to determine the infectious dose of SVA in market weight and neonatal pigs. A 2011 SVA isolate was serially hundred-fold diluted to create four challenge inoculums ranging from 106.5 to 100.5 TCID50/ml. Four market weight pigs individually housed were intranasally inoculated with 5 mL of each dose (n = 16). Serial ten-fold dilutions were used to create 6 challenge inoculums ranging from 105.5 to 100.5 TCID50/ml for neonatal pigs. Again, four animals in individual housing were challenged orally with 2 mL of each dose (n = 24). Detection of SVA by PCR in collected samples and/or neutralizing antibody response was utilized to classify an animal as infected. The minimum infectious dose for this study in market weight animals was 1,260 TCID50/ml (103.1 TCID50/ml) and for neonates it was 316 TCID50/ml (102.5 TCID50/ml). Knowledge of the infectious dose of SVA can guide biosecurity and disinfection measures to control the spread of SVA. [ABSTRACT FROM AUTHOR]

Foot-and-mouth disease virus (FMDV) and classical swine fever virus (CSFV) possess positive-sense single-stranded RNA genomes and an internal ribosomal entry site (IRES) element within their 5′-untranslated regions. To investigate the common host factors associated with these IRESs, we established cell lines expressing a bicistronic luciferase reporter plasmid containing an FMDV-IRES or CSFV-IRES element between the Renilla and firefly luciferase genes. First, we treated FMDV-IRES cells with the French maritime pine extract, Pycnogenol (PYC), and examined its suppressive effect on FMDV-IRES activity, as PYC has been reported to have antiviral properties. Next, we performed microarray analysis to identify the host factors that modified their expression upon treatment with PYC, and confirmed their function using specific siRNAs. We found that polycystic kidney disease 1-like 3 (PKD1L3) and ubiquitin-specific peptidase 31 (USP31) were associated with FMDV-IRES activity. Moreover, silencing of these factors significantly suppressed CSFV-IRES activity. Thus, PKD1L3 and USP31 are host factors associated with the functions of FMDV- and CSFV-IRES elements. [ABSTRACT FROM AUTHOR]

Five PCV2 strains identified in this study showed the highest nt identities (99.2-100%) to PCV2 strains retrieved from the GenBank database whilst strain ITA/2021/434 was more distantly related (88.8% nt identity) to strain 71b Vicenza 36 (GenBank accession nr KP231135) identified from a domestic pig in Italy in 2008. The complete PCV genome sequence was obtained only from 11 (5 PCV2 and 6 PCV3) Italian wild boar (Table S4). The prevalence of PCV3 in wild boar in our survey was nearly as high (71%) as in Sardinia Island (77.39% in free ranging pigs and 61.54% in wild boar) [[17]], but higher than the prevalence of PCV3 detected in the Campania region (49.32%) [[15]] and in other Mediterranean countries (e.g., 42.66% in Spain) [[11]]. [Extracted from the article]

Background: Seneca Valley virus (SVV) is a picornavirus that causes vesicular disease in swine. Clinical characteristics of the disease are similar to common viral diseases such as foot-and-mouth disease virus, porcine vesicular disease virus, and vesicular stomatitis virus, which can cause vesicles in the nose or hoof of pigs. Therefore, developing tools for detecting SVV infection is critical and urgent. Methods: The neutralizing antibodies were produced to detect the neutralizing epitope. Results: Five SVV neutralizing monoclonal antibodies (mAb), named 2C8, 3E4, 4C3, 6D7, and 7C11, were generated by immunizing mouses with ultra-purified SVV-LNSY01-2017. All five monoclonal antibodies exhibited high neutralizing titers to SVV. The epitopes targeted by these mAbs were further identified by peptide scanning using GST fusion peptides. The peptide 153QELNEE158 is defined as the smallest linear neutralizing epitope. The antibodies showed no reactivity to VP2 single mutants E157A. Furthermore, the antibodies showed no neutralizing activity with the recombinant virus (SVV-E157A). Conclusions: The five monoclonal antibodies and identified epitopes may contribute to further research on the structure and function of VP2 and the development of diagnostic methods for detecting different SVV strains. Additionally, the epitope recognized by monoclonal antibodies against VP2 protein may provide insights for novel SVV vaccines and oncolytic viruses development. [ABSTRACT FROM AUTHOR]

Tildipirosin is a macrolide currently authorized for treating respiratory diseases in cattle and swine. The disposition kinetics of tildipirosin in plasma, milk, and somatic cells were investigated in dairy goats. Tildipirosin was administered at a single dose of 2 mg/kg by intravenous (IV) and 4 mg/kg by intramuscular (IM) and subcutaneous (SC) routes. Concentrations of tildipirosin were determined by an HPLC method with UV detection. Pharmacokinetic parameters were estimated by non-compartmental analysis. Muscle damage, cardiotoxicity, and inflammation were evaluated. After IV administration, the apparent volume of distribution in the steady state was 7.2 L/kg and clearance 0.64 L/h/kg. Plasma and milk half-lives were 6.2 and 58.3 h, respectively, indicating nine times longer persistence of tildipirosin in milk than in plasma. Moreover, if somatic cells are considered, persistence and exposure measured by the area under concentration–time curve (AUC) significantly exceeded those obtained in plasma. Similarly, longer half-lives in whole milk and somatic cells compared to plasma were observed after IM and SC administration. No adverse effects were observed. In brief, tildipirosin should be reserved for cases where other suitable antibiotics have been unsuccessful, discarding milk production of treated animals for at least 45 days or treating goats at the dry-off period. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Veterinary Research / Revue Canadienne de Recherche Vétérinaire is the property of Canadian Veterinary Medical Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Veterinary Research / Revue Canadienne de Recherche Vétérinaire is the property of Canadian Veterinary Medical Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

African swine fever virus causes hemorrhagic disease in swine. Attenuated strains are reported in Africa, Europe, and Asia. Few studies on the diagnostic detection of attenuated ASF viruses are available. Two groups of pigs were inoculated with an attenuated ASFV. Group 2 was also vaccinated with an attenuated porcine reproductive and respiratory syndrome virus vaccine. Commercially available ELISA, as well as extraction and qPCR assays, were used to detect antibodies in serum and oral fluids (OF) and nucleic acid in buccal swabs, tonsillar scrapings, OF, and blood samples collected over 93 days, respectively. After 12 dpi, serum (88.9% to 90.9%) in Group 1 was significantly better for antibody detection than OF (0.7% to 68.4%). Group 1′s overall qPCR detection was highest in blood (48.7%) and OF (44.2%), with the highest detection in blood (85.2%) from 8 to 21 days post inoculation (dpi) and in OF (83.3%) from 1 to 7 dpi. Group 2′s results were not significantly different from Group 1, but detection rates were lower overall. Early detection of attenuated ASFV variants requires active surveillance in apparently healthy animals and is only reliable at the herd level. Likewise, antibody testing will be needed to prove freedom from disease. [ABSTRACT FROM AUTHOR]

African swine fever (ASF) is a swine disease with a very high fatality rate caused by a complex double-stranded DNA virus. The fluorescence PCR detection method is widely used for virus nucleic acid detection. Surface plasmon resonance (SPR) is a label-free and real-time detection method, unlike the fluorescence PCR detection method. In this research, we detected the loop-mediated isothermal amplification (LAMP) products of the African swine fever virus by using the SPR and fluorescence methods separately and simultaneously. By comparing the positive and negative control results, we found that the SPR response unit is completely different before and after the LAMP process. In addition, the fluorescence results on a chip showed that with an increase in the concentration of the sample, the cycle threshold (CT) value decreased, which is consistent with commercial instruments. Both the decline rate of the SPR response unit and the CT value of the fluorescence realized were used to distinguish the positive control from the negative control and water, which indicates that the SPR method can be combined with fluorescence to detect LAMP products. This research provides a label-free and simple method for detecting LAMP products. [ABSTRACT FROM AUTHOR]

• An inactivated Senecavirus A vaccine was efficacious against challenge. • Piglets suckling immunized dams were protected against challenge. • Increased neonatal mortality was not observed in challenged piglets. Senecavirus A (SVA), commonly known as Seneca Valley virus (SVV) is a causative agent for vesicular disease in swine. It has been found across the globe including the United States, Brazil, and China. Clinical disease caused by this virus is identical to foot-and-mouth disease virus (FMDV). Since FMDV has the potential to cause severe economic consequences in FMDV-free countries, those countries are on high alert for signs of vesicles in swine and an investigation is performed to rule out the presence of FMDV if observed. In countries where SVA cases have continued to occur, investigations and testing can cause a burden on personnel and resources. The objectives of this study were to test the efficacy of a whole-virus inactivated SVA vaccine against challenge in nursery-aged pigs, mature sows, and to assess the protection of passive maternal immunity generated by immunized dams. Animals were given two doses of the vaccine intramuscularly three weeks apart and challenged intranasally two weeks after the second dose. Non-vaccinated animals challenged with SVA developed clinical signs of disease, replicated virus, and developed a neutralizing antibody response. Vaccinated animals had robust neutralizing titers after two doses; and after challenge, did not develop vesicular disease and had limited rectal shedding. Piglets suckling immunized dams and challenged with SVA at 3–6 days-of-age had neutralizing titers prior to challenge and did not replicate or shed virus. An efficacious vaccine could improve swine welfare and reduce the economic consequences of continued foreign animal disease investigations. [ABSTRACT FROM AUTHOR]

Senecavirus A (SVA) is a new type of virus related to swine vesicular disease, which results in enormous economic losses worldwide. At present, the host transcriptional responses to SVA infection, host-SVA interactions, and the mechanism of SVA in innate immune modulation are not well understood. This study explores the gene expression profiles of PK-15 cells at 0, 6, 12, 18, 24, 36 h SVA post-infection by RNA sequencing. Our analysis identified 61, 510, 1,584, 2,460, and 2,359 differentially expressed genes (DEGs) in the comparison groups S6 vs. Control, S12 vs. Control, S18 vs. Control, S24 vs. Control, S36 vs. Control, respectively. The reproducibility and repeatability of the results were validated by RT-qPCR, and all DEGs exhibited expression patterns consistent with the RNA-seq results. According to GO enrichment analysis and KEGG pathway analysis of DEGs in different periods after SVA infection, we found that SVA infection significantly modified the host cell gene-expression patterns and the host cells responded in highly specific manners, including response to signal reception and transmission, external biotic stimulus, response to the virus and host immune defense response. Notably, we observed the specific induction of type III interferon IFN-λ1 and IFN-λ3, which indicated that type III interferon plays an important antiviral function in PK-15 cells. Furthermore, our results showed that SVA might be recognized by RIG-I/MDA-5 receptors first after infecting PK-15 cells and then activates downstream IRF7-mediated signaling pathways, causing an increase in the expression of type III interferon. This study could provide important insights into the modulation of host metabolism during SVA infection and provide a strong theoretical basis for a better understanding of the pathogenic mechanism and immune escape mechanism of SVA. [ABSTRACT FROM AUTHOR]

African swine fever (ASF) is a contagious, hemorrhagic and highly lethal viral disease in swine. Following the initial report of ASF in Kenya in 1921 it spread to East Asia through Western Europe and Russia (including Eastern Europe). Many efforts have been dedicated to controlling ASF but the struggle to eradicate this disease continues. Thus far, the efforts to develop an effective vaccine to control ASF have been unsuccessful. A previous inactivated ASF vaccine, developed by traditional methods, failed to protect pigs from ASF virus (ASFV) infection. Neutralizing antibodies were not effective in inducing protective immunity and it appears that cellular immunity is required. To develop an effective ASF vaccine the identification of protective antigens of ASFV has been explored and subunit vaccines that target these potential protective antigens have induced partial protection. DNA vaccines that induce cellular immunity have been effective in inducing protection against ASFV infection. ASFV live attenuated vaccines (LAVs) can be rationally designed and engineered via comparative and functional genomics. LAVs have a major safety concern despite their high protective efficacy. ASF vaccines are urgently needed to control ASF; however, many obstacles remain to be overcome to develop an effective ASF vaccine. [ABSTRACT FROM AUTHOR]

African swine fever (ASF) and classical swine fever (CSF) are contagious swine diseases that are clinically indistinguishable from each other; hence, reliable test methods for accurate diagnosis and differentiation are highly demanded. By employing a buffer system suitable for crude extraction of nucleic acids together with an impurity-tolerant enzyme, we established a multiplex assay of real-time reverse-transcription polymerase chain reaction (rRT-PCR) for simultaneous detection of ASF virus (ASFV), CSF virus (CSFV) and swine internal control derived genes in a sample without the need for prior purification of viral nucleic acids. We applied this method to test serum and tissue samples of infected pigs and wild boars and compared the statistical sensitivities and specificities with those of standard molecular diagnostic methods. When a serum was used as a test material, the newly established assay showed 94.4% sensitivity for both and 97.9 and 91.9% specificity for ASFV and CSFV detection, respectively. In contrast, the results were 100% identical with those obtained by the standard methods when a crude tissue homogenate was used as a test material. The present data indicate that this new assay offers a practical, quick, and reliable technique for differential diagnosis of ASF and CSF where geographical occurrences are increasingly overlapping. [ABSTRACT FROM AUTHOR]

A limited understanding of the transmission dynamics of swine disease is a significant obstacle to prevent and control disease spread. Therefore, understanding between‐farm transmission dynamics is crucial to developing disease forecasting systems to predict outbreaks that would allow the swine industry to tailor control strategies. Our objective was to forecast weekly porcine epidemic diarrhoea virus (PEDV) outbreaks by generating maps to identify current and future PEDV high‐risk areas, and simulating the impact of control measures. Three epidemiological transmission models were developed and compared: a novel epidemiological modelling framework was developed specifically to model disease spread in swine populations, PigSpread, and two models built on previously developed ecosystems, SimInf (a stochastic disease spread simulations) and PoPS (Pest or Pathogen Spread). The models were calibrated on true weekly PEDV outbreaks from three spatially related swine production companies. Prediction accuracy across models was compared using the receiver operating characteristic area under the curve (AUC). Model outputs had a general agreement with observed outbreaks throughout the study period. PoPS had an AUC of 0.80, followed by PigSpread with 0.71, and SimInf had the lowest at 0.59. Our analysis estimates that the combined strategies of herd closure, controlled exposure of gilts to live viruses (feedback) and on‐farm biosecurity reinforcement reduced the number of outbreaks. On average, 76% to 89% reduction was seen in sow farms, while in gilt development units (GDU) was between 33% to 61% when deployed to sow and GDU farms located in probabilistic high‐risk areas. Our multi‐model forecasting approach can be used to prioritize surveillance and intervention strategies for PEDV and other diseases potentially leading to more resilient and healthier pig production systems. [ABSTRACT FROM AUTHOR]

Porcine reproductive and respiratory syndrome (PRRS) and pseudorabies (PR) are highly infectious swine diseases and cause significant financial loss in China. The respiratory system and reproductive system are the main target systems. Previous studies showed that the existing PR virus (PRV) and PRRS virus (PRRSV) commercial vaccines could not provide complete protection against PRV variant strains and NADC30-like PRRSV strains in China. In this study, the PRV variant strain XJ and NADC30-like PRRSV strain CHSCDJY-2019 are used as the parent for constructing a recombinant pseudorabies virus (rPRV)-NC56 with gE/gI/TK gene deletion and co-expressing NADC30-like PRRSV GP5 and M protein. The rPRV-NC56 proliferated stably in BHK-21 cells, and it could stably express GP5 and M protein. Due to the introduction of the self-cleaving 2A peptide, GP5 and M protein were able to express independently and form virus-like particles (VLPs) of PRRSV in rPRV-NC56-infected BHK-21 cells. The rPRV-NC56 is safe for use in mice; it can colonize and express the target protein in mouse lungs for a long time. Vaccination with rPRV-NC56 induces PRV and NADC30-like PRRSV specific humoral and cellular immune responses in mice, and protects 100% of mice from virulent PRV XJ strain. Furthermore, the virus-neutralizing antibody (VNA) elicited by rPRV-NC56 showed significantly lower titer against SCNJ-2016 (HP-PRRSV) than that against CHSCDJY-2019 (NADC30-like PRRSV). Thus, rPRV-NC56 appears to be a promising candidate vaccine against NADC30-like PRRSV and PRV for the control and eradication of the variant PRV and NADC30-like PRRSV. [ABSTRACT FROM AUTHOR]

Coinfection with multiple viruses is a common phenomenon in clinical settings and is a crucial driver of viral evolution. Although numerous studies have demonstrated viral recombination arising from coinfections of different strains of a specific species, the role of coinfections of different species or genera during viral evolution is rarely investigated. Here, we analyzed coinfections of and recombination events between four different swine enteric coronaviruses that infect the jejunum and ileum in pigs, including porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), and swine acute diarrhea syndrome coronavirus (SADS-CoV), and a deltacoronavirus, porcine deltacoronavirus (PDCoV). Various coinfection patterns were observed in 4,468 fecal and intestinal tissue samples collected from pigs in a 4-year survey. PEDV/PDCoV was the most frequent coinfection. However, recombination analyses have only detected events involving PEDV/TGEV and SADS-CoV/TGEV, indicating that inter-species recombination among coronaviruses is most likely to occur within the same genus. We also analyzed recombination events within the newly identified genus Deltacoronavirus and found that sparrows have played a unique host role in the recombination history of the deltacoronaviruses. The emerging virus PDCoV, which can infect humans, has a different recombination history. In summary, our study demonstrates that swine enteric coronaviruses are a valuable model for investigating the relationship between viral coinfection and recombination, which provide new insights into both inter- and intraspecies recombination events among swine enteric coronaviruses, and extend our understanding of the relationship between coronavirus coinfection and recombination.