Hunting for a viral proxy in bioaerosols of swine buildings using molecular detection and metagenomics.

There are limited biosecurity measures directed at preventing airborne transmission of viruses in swine. The effectiveness of dust mitigation strategies such as oil sprinkling, to decrease risk of airborne virus transmission are unknown. Metagenomics and qPCR for common fecal viruses were used to hunt for a ubiquitous virus to serve as a proxy when evaluating the efficiency of mitigation strategies against airborne viral infectious agents. Air particles were collected from swine buildings using high-volume air samplers. Extracted DNA and RNA were used to perform specific RT-qPCR and qPCR and analyzed by high-throughput sequencing. Porcine astroviruses group 2 were common (from 102 to 105 genomic copies per cubic meter of air or gc/m3, 93% positivity) while no norovirus genogroup II was recovered from air samples. Porcine torque teno sus virus were detected by qPCR in low concentrations (from 101 to 102 gc/m3, 47% positivity). Among the identified viral families by metagenomics analysis, Herelleviridae, Microviridae, Myoviridae, Podoviridae, and Siphoviridae were dominant. The phage vB_AviM_AVP of Aerococcus was present in all air samples and a newly designed qPCR revealed between 101 and 105 gc/m3 among the samples taken for the present study (97% positivity) and banked samples from 5- and 15-year old studies (89% positivity). According to the present study, both the porcine astrovirus group 2 and the phage vB_AviM_AVP of Aerococcus could be proxy for airborne viruses of swine buildings.

Establishment of a swine model of delayed bleeding after endoscopic procedure.

Objectives: Although delayed bleeding after endoscopic procedures has become a problem, currently, there are no appropriate animal models to validate methods for preventing it. This study aimed to establish an animal model of delayed bleeding after endoscopic procedures of the gastrointestinal tract. Methods: Activated coagulation time (ACT) was measured using blood samples drawn from a catheter inserted into the external jugular vein of swine (n = 7; age, 6 months; mean weight, 13.8 kg) under general anesthesia using the cut-down method. An upper gastrointestinal endoscope was inserted orally, and 12 mucosal defects were created in the stomach by endoscopic mucosal resection using a ligating device. Hemostasis was confirmed at this time point. The heparin group (n = 4) received 50 units/kg of unfractionated heparin via a catheter; after confirming that the ACT was ≥200 s 10 min later, continuous heparin administration (50 units/kg/h) was started. After 24 h, an endoscope was inserted under general anesthesia to evaluate the blood volume in the stomach and the degree of blood adherence at the site of the mucosal defect. Results: Delayed bleeding was observed in three swine (75%) in the heparin-treated group, who had a maximum ACT of >220 s before the start of continuous heparin administration. In the non-treated group (n = 3), no prolonged ACT or delayed bleeding was observed at 24 h. Conclusion: An animal model of delayed bleeding after an endoscopic procedure in the gastrointestinal tract was established using a single dose of heparin and continuous heparin administration after confirming an ACT of 220 s.

A recombinant pseudorabies virus surface - displaying the classical swine fever E2 protein induces specific antibodies rapidly.

Pseudorabies virus (PRV) and classical swine fever virus (CSFV) are both economically important pathogens threatening the pig industry in many countries. The triple-gene-deleted variant of PRV, herein referred to as rPRVTJ-delgE/gI/TK, has exhibited pronounced efficacy and safety profiles. This underscores its viability as a prospective vaccine vector. However, the generation of specific anti-E2 antibodies necessitates elevated immunization doses and extended durations when the extracellular domain of the E2 protein of CSFV is secreted via the recombinant rPRVTJ-delgE/gI/TK vector. To enhance the presentation of exogenous antigens by antigen-presenting cells (APCs), we engineered the E2 protein expressed on the surface of PRV particles in this study. The recombinant virus expressing the E2 protein with a heterogonous transmembrane domain was generated in the backbone of rPRVTJ-delgE/gI/TK and designated as rPRVTJ-UL44-E2. The E2 gene was fused to the 3' terminus of the UL44 gene utilizing P2A, a self-cleaving peptide sequence. The electron microscopy showed that the E2 protein was anchored on the surface of the viral particles of rPRVTJ-delgE/gI/TK-E2. The insertion of the E2 gene did not alter the native biological characteristics of the viral vector. Rabbits immunized with 107 median tissue culture infective doses (TCID50) of rPRVTJ-UL44-E2 exhibited a rapid seroconversion to anti-E2 specific antibodies within 7 days post-immunization (dpi). All the rabbits immunized with the rPRVTJ-UL44-E2 had generated antibodies specific to E2 prior to the administration of the booster immunization. However, the immunized rabbits were not protected from the CSFV C-strain challenge. Nevertheless, this strategy has notably achieved rapid induction of E2-specific non-neutralizing antibodies. These findings provide insights that the design of rPRVTJ-UL44-E2 requires optimization, thereby indicating a promising avenue for augmenting vaccine-induced immune responses.

Rapid detection of African swine fever virus via SERS probe-modified sandwich hybridization assay.

Rapid and reliable detection method for African swine fever virus (ASFV) is proposed by surface-enhanced Raman spectroscopy (SERS). The ASFV target DNA can be specifically captured by sandwich hybridization between nanomagnetic beads and a SERS probe. Experimental results show that the significant Raman signal of the SERS probe with gold nanoparticles and a molecular reporter DTNB (5,5'-dimercapto-bis (2-nitrobenzoic acid)) can be adopted for detecting the hybridization chain reaction of ASFV DNA. The advantage of the SERS sandwich hybridization assay is the large response range from the single molecule level to 108 copies per mL, which not only can overcome the tedious time required for the amplification reaction but also provides a comparative method to polymerase chain reaction. Furthermore, real samples of African swine fever virus were detected from different subjects of swine fever virus including porcine reproductive respiratory syndrome virus and Japanese encephalitis virus. The proposed biosensor method can rapidly detect ASFV correctly within 15 min as a simple, convenient, low-cost detection approach. The biosensor can be used as a platform for the determination in biological, food, and environmental analytical fields.

Development of a rapid and reliable surveillance method for Ornithodoros turicata americanus in gopher tortoise (Gopherus polyphemus) burrows in the southeastern United States.

The soft tick Ornithodoros turicata Duges (Acari: Argasidae) is a potential vector of African swine fever virus (ASFV). We evaluated the efficacy of two methods to collect soft ticks rapidly and efficiently from gopher tortoise (Gopherus polyphemus) burrows, which are ubiquitous throughout large regions of the southeastern United States and their burrows are a known microhabitat of O. turicata. Burrow vacuuming was an effective and efficient tick collection method; no tick was captured employing CO2 trapping. Using an occupancy modelling framework, we estimated that the probability of detecting ticks from an infested burrow each time a sample was taken with this method was 58% and increased with the average relative humidity. With the occupancy model, we estimated that 70% of the burrows in the study area were infested with O. turicata. Manual sifting of the burrow material yielded more ticks (6.6 individuals/sample) than using a set of three sieves (2.9 individuals/sample), yet the probability of detecting the species was not different between the two methods (Pval = 0.7). These methods can inform the development of ASF vector surveillance and outbreak response plans in areas of high risk for ASFV introduction in the region.

Antiviral activity of SAFER®, a commercial acidifying desiccant powder, against African swine fever virus.

African swine fever (ASF) is one of the deadliest swine diseases, causing significant economic losses, threatening food security, and limiting pig production in affected countries. In the absence of an effective ASF vaccine, prevention and control of ASF depend mainly on effective biosecurity measures. In this study, the efficacy of SAFER®, a powdered disinfectant containing clay, an acid complex, and the active ingredient thyme essential oil, was tested against the ASF virus. The results showed that ASFV isolate (VNUA/HY/ASF1/Vietnam/2019) was inactivated by 3.5 and 5 Log10HAD50/ml after 20 and 120 min of treatment with SAFER®, respectively. When body fluids contaminated with ASFV, such as blood, saliva, urine, and feces, were treated with SAFER® for 20 min, the ASFV titer was reduced by 1.6, 2.2, 2.0, and 2.2 Log10HAD50/ml, respectively.

Evaluation of an in-house indirect immunoperoxidase test for detection of antibodies against African swine fever virus.

African swine fever (ASF) is a high-consequence transboundary animal disease caused by African swine fever virus (ASFV). Given that vaccines are not widely available, ASFV detection, including by molecular and serologic assays, is paramount to efficacious control and mitigation of ASF. ASFV-specific antibodies can be detected as early as 7-10 d postinfection in infected animals and may persist for several months or longer. Accurate detection of ASFV-specific antibody is critical for the identification of chronically infected, subclinically infected, or recovered animals. ELISAs are commonly used for the rapid screening of large numbers of animals for ASFV antibodies. The World Organisation for Animal Health recommends that ELISA-positive results should be confirmed with a second serologic method, such as an indirect immunofluorescent assay, indirect immunoperoxidase test (IPT), or immunoblot test. Commercial kits are not available for those tests. We developed and validated an in-house IPT by using a currently circulating genotype II ASFV strain as antigen. The sensitivity and specificity of the in-house IPT are comparable to the reference IPT developed by an international ASFV reference laboratory and superior to a commercial blocking ELISA.

Immune responses induced by a recombinant C-strain of classical swine fever virus expressing the F317L protein of African swine fever virus.

African swine fever (ASF), a highly infectious and devastating disease affecting both domestic pigs and wild boars, owes its etiology to African swine fever virus (ASFV). ASFV encodes more than 165 proteins. However, novel immunogenic proteins remain unknown. This study aimed to determine the antigenicity of the F317L protein (pF317L) of ASFV. The results revealed that pF317L was able to react with convalescent pig sera, indicating that pF317L could be a candidate antigen. The antigenic potential of pF317L expressed by rHCLV-F317L, a recombinant virus in the backbone of C-strain (a lapinized live attenuated classical swine fever virus) was further investigated in rabbits and pigs. The results revealed that antibodies and cell-mediated immune responses against pF317L were induced in either rabbits or pigs inoculated with rHCLV-F317L. Importantly, anti-pF317L antibodies from rabbits or pigs immunized with rHCLV-F317L significantly inhibited ASFV replication in vitro. In conclusion, pF317L demonstrates favorable immunogenic properties, positioning it as a promising candidate for the development of protective antigens in the ongoing endeavor to formulate efficacious ASF vaccine strategies.

A translational study evaluating a ruggedized portable oxygen concentrator versus an oxygen cylinder in simulated polytrauma intubation of swine.

Objectives: Portable oxygen concentrators (POCs) are medical devices that use filters to selectively remove nitrogen from ambient air to produce concentrated, medical-grade oxygen. This is the first study to evaluate a ruggedized POC's performance during simulated polytrauma intubation. Methods: Twenty-seven swine were intubated and anesthetized with ketamine. At T = 0, animals were extubated, received a chest wall injury, a tibia fracture, and 20% total blood volume controlled hemorrhage was initiated. At T = 10 min, the swine were pre-oxygenated using a bag-valve mask connected to one of three randomized oxygen sources: (1) a ruggedized POC, (2) a M-15 oxygen cylinder, or (3) room air (control). At T = 12 min, animals were re-intubated to simulate polytrauma intubation and connected to the test oxygen source for the remainder of the experiment. Surviving animals entered a 2-h period where partial pressure of oxygen (PaO2), oxygen saturation (SpO2), and regional oxygen saturation (rSO2) were monitored. Groups were compared using analysis of variance (ANOVA), Fisher's exact, log-rank analysis, or mixed-effects model as appropriate. Results: All animals survived except one in the POC group. Mixed-effects models revealed differences between groups with regards to PaO2 (p < 0.0001) and SpO2 (p = 0.006). Based on post hoc analysis, oxygen cylinder PaO2 was superior to both POC and control, but there were no differences between POC and control PaO2. There were statistically and clinically significant differences in SpO2 during periods of pre-oxygenation (T = 10‒12 min), intubation (T = 12‒14 min), and immediately after intubation (T = 14‒20 min). The POC battery was consumed in 43 ± 13 min. Conclusion: In our swine model, a single, ruggedized POC provided inferior amounts of oxygen supplementation compared to an oxygen cylinder and performed no better than room air.

Protein is expressed in all major organs after intravenous infusion of mRNA-lipid nanoparticles in swine.

In vivo delivery of mRNA is promising for the study of gene expression and the treatment of diseases. Lipid nanoparticles (LNPs) enable efficient delivery of mRNA constructs, but protein expression has been assumed to be limited to the liver. With specialized LNPs, delivery to extrahepatic tissue occurs in small animal models; however, it is unclear if global delivery of mRNA to all major organs is possible in humans because delivery may be affected by differences in innate immune response and relative organ size. Furthermore, limited studies with LNPs have been performed in large animal models, such as swine, due to their sensitivity to complement activation-related pseudoallergy (CARPA). In this study, we found that exogenous protein expression occurred in all major organs when swine were injected intravenously with a relatively low dose of mRNA encapsulated in a clinically relevant LNP formulation. Exogenous protein was detected in the liver, spleen, lung, heart, uterus, colon, stomach, kidney, small intestine, and brain of the swine without inducing CARPA. Furthermore, protein expression was detected in the bone marrow, including megakaryocytes, hematopoietic stem cells, and granulocytes, and in circulating white blood cells and platelets. These results show that nearly all major organs contain exogenous protein expression and are viable targets for mRNA therapies.

Porcine astrovirus 3 RNA in the central nervous system of weaned pigs with neurologic disease and polioencephalomyelitis in Brazil.

This report aims to describe the identification of porcine astrovirus 3 (PAstV3) RNA in the central nervous system (CNS) of weaned pigs with clinical signs of neurological disease associated with polioencephalomyelitis in southeastern Brazil. Three, 20 -35 days-old piglets that died after clinical manifestations of a neurological syndrome were submitted to post-mortem evaluations. Tissue samples were examined by histopathology, bacteriology, and molecular assays (RT-PCR, nested-PCR, RT-qPCR, and Sanger sequencing) to detect the primary infectious disease agents associated with neurological disease in pigs. The principal neuropathological alterations occurred in the grey matter of the spinal cord and brainstem resulting in nonsuppurative poliomyelitis and rhombencephalitis. PAstV3 RNA was detected in the CNS samples of all piglets with histopathological evidence of disease and was confirmed by nucleotide sequencing. Nucleic acids from pathogens commonly associated with neurological diseases in pigs, such as porcine teschovirus, porcine sapelovirus, porcine enterovirus G, atypical porcine pestivirus, senecavirus A, and encephalomyocarditis virus was not detected by molecular assays in the three piglets. This is the first report of PAstV3 in piglets with neurological disease and lesions consistent with polioencephalomyelitis in Brazil. This report highlights the importance of monitoring health events that could compromise pig farming productivity and animal welfare.

Lack of detection of Porcine circovirus 3 (PCV-3) in formalin-fixed, paraffin- embedded tissues from porcine abortions in Switzerland.

INTRODUCTION: The novel Porcine circovirus 3 (PCV-3) has been associated in the past years to different porcine diseases, including reproductive failure. The potential occurrence of PCV-3 in abortions from Swiss pig herds has not been investigated so far. Thus, we conducted a retrospective study on pig aborted cases submitted to our laboratory in the University of Bern during the last 10 years with the main aim of investigating the possible presence of PCV-3 in foetal and/or placental tissue. Twelve out of the 53 studied cases showed mild histopathological changes as previously described in PCV-3 positive cases. However, in none of the cases, PCV-3 genetic material could be detected in the examined formalin-fixed, paraffin-embedded tissues. In only one third of the cases, a cause for the abortion was found, which is similar to other studies. Our survey suggests that PCV-3 was not involved in the porcine abortion cases submitted over the last decade at our institution in Switzerland.

INTRODUCTION: Le nouveau Circovirus porcin 3 (PCV-3) a été associé ces dernières années à différentes maladies porcines, y compris des troubles de la reproduction. La présence potentielle du PCV-3 dans les avortements de porcs en Suisse n'a pas été étudiée jusqu'à présent. Nous avons donc mené une étude rétrospective sur les cas d'avortements de porcs soumis à notre laboratoire de l'Université de Berne au cours des 10 dernières années, dans le but principal d'étudier la présence éventuelle du PCV-3 dans les tissus fœtaux et/ou placentaires. Douze des 53 cas étudiés présentaient des changements histopathologiques légers, tels que décrits précédemment dans les cas positifs au PCV-3. Cependant, dans aucun des cas, le matériel génétique du PCV-3 n'a pu être détecté dans les tissus examinés fixés au formol et inclus en paraffine. Dans un tiers des cas seulement, une cause d'avortement a été trouvée, ce qui est similaire à d'autres études. Notre étude suggère que le PCV-3 n'a pas été impliqué dans les cas d'avortements porcins soumis au cours de la dernière décennie dans notre institution en Suisse.

The contribution of swine wastewater on environmental pathogens and antibiotic resistance genes: Antibiotic residues and beyond.

Swine wastewater application can introduce antibiotics, antibiotic resistance genes (ARGs) into environments. Herein, the full-scale transmission of antibiotics, ARGs and their potential carriers from an intensive swine feedlot to its surroundings were explored. Results showed that lincomycin and doxycycline hydrochloride were dominant antibiotics in this ecosystem. Lincomycin concentration were strongly associated with soil bacterial communities. According to the risk quotient (RQ), lincomycin was identified as posing higher ecological risk in aquatic environments. ARGs and mobile genetic elements (MGEs) abundance in wastewater were reduced after anaerobic treatment. Notably, ARGs composition of environmental samples were clustered into two groups based on if they were directly affected by the wastewater. However, there were no remarkable difference of ARGs abundance among environmental samples. The total abundance of ARGs was positively related to that of MGEs. Pathogens Escherichia coli and Enterococcus revealed strong connection with qnrS, tet and sul. Overall, this study highlights the importance of responsible antibiotics use in livestock production and appropriate treatment technology before agricultural application and discharge.

Computational investigation in inhibitory effects of amantadine on classical swine fever virus p7 ion channel activity.

Classical swine fever virus (CSFV) p7 viroporin plays crucial roles in cellular ion balance and permeabilization. The antiviral drug amantadine effectively inhibits viral replication by blocking the activity of CSFV p7 viroporin. However, little information is available for the binding mode of amantadine with CSFV p7 viroporin, due to the lack of a known polymer structure for CSFV p7. In this study, we employed AlphaFold2 to predict CSFV p7 structures. Subsequently, we conducted a docking study to investigate the binding sites of amantadine to CSFV p7. Computational analysis showed that CSFV p7 forms a pore channel in a hexameric structure. Furthermore, molecular dynamics (MD) simulations and mutant analyses further suggest that CSFV p7 likely exists as a hexamer. Docking studies and MD simulations showed that amantadine interacts with the hydrophibic regions of tetramer and pentamer, as well as with the hydrophobic pore channel of the hexamer. Considering the potential hexameric assembly of CSFV p7, along with docking results, MD simulations, and the characteristics of the gated ion channels, we propose a model of CSFV p7 ion channel based on its hexameric configuration. In this model, residues E21, Y25, and R34 are suggested to selectively recruit and dehydrate ions, while residues L28 and L31 likely act as hydrophobic constrictors, thereby restricting the free movement of water. The binding of amantadine to residues I20, E21, V24 and Y25 effectively blocks ion transport. However, this proposed molecular model requires experimental validation. Our findings give a structural insight into the models of CSFV p7 as an ion channel and provide a molecular explanation for the inhibition effects of amantadine on CSFV p7-mediated ion channel conductance.

Validation of a direct multiplex real-time reverse transcription PCR assay for rapid detection of African swine fever virus using swine field samples in Vietnam.

OBJECTIVE: This study validates a direct multiplex real-time reverse transcription polymerase chain reaction (rRT-PCR) assay which was previously established for enabling rapid and simultaneous detection of African swine fever (ASF) virus (ASFV) and classical swine fever virus. The assay eliminates the need for viral nucleic acid purification using a buffer system for crude extraction and an impurity-tolerant enzyme. However, the assay had not yet been validated using field samples of ASFV-infected pigs. Therefore, to address this gap, we tested 101 samples collected from pigs in Vietnam during 2018 and 2021 for validation. RESULTS: The rRT-PCR assay demonstrated a diagnostic sensitivity of 98.8% and a specificity of 100%. Remarkably, crude samples yielded results comparable to those of purified samples, indicating the feasibility of using crude samples without compromising accuracy in ASFV detection. Our findings emphasize the effectiveness of the rRT-PCR assay for the prompt and accurate diagnosis of both swine fever viruses, which is essential for effective disease prevention and control in swine populations.

An immunoassay based on bioluminescent sensors for rapid detection of African swine fever virus antibodies.

Serological assays for antibody detection have contributed significantly to the diagnosis and control of infectious diseases. African swine fever is the most devastating infectious disease of domestic pigs and wild boars, severely threatening the global pig industry in recent years. Here, we developed a rapid, simple, and sensitive immunoassay based on the split-luciferase system to detect IgG antibodies against African swine fever virus (ASFV). In this assay, the p30 protein of ASFV was genetically coupled to the LgBiT and SmBiT subunits of nanoluciferase, which were used as fusion probes for specific antibodies. Target engagement of the probes results in the reconstitution of a functional nanoluciferase, which further catalyzes bioluminescent reactions. Different orientations of the LgBiT and SmBiT-p30 fusion sensors were designed and investigated, and N-LgBiT/p30 and N-SmBiT/p30 were identified as a promising sensor pair for reforming active nanoluciferase in the presence of specific antibodies. After optimization, this split-luciferase complementation assay showed high sensitivity and specificity for the detection of ASFV antibodies. The analytical sensitivity of the assay was 16 times greater than that of the blocking enzyme-linked immunosorbent assay (ELISA) by the detection of serial dilutions of serum, and no cross-reaction was observed with other swine pathogens. As demonstrated in clinical samples, its performance is highly consistent with that of a commercial ELISA kit, with a concordance rate of 98.19%. This assay is simple and easy to perform, providing a more flexible and efficient approach for the measurement of ASFV antibodies in clinical applications. IMPORTANCE: The study is about a homogeneous split-luciferase assay for antibody detection. Split nanoluciferase biosensors for the detection of ASFV antibodies were designed. This sensor platform enables the sensitive and specific detection of antibodies. The split-luciferase assay is simple, rapid, and easy to use.

Reagent-free phosphorus precipitation from a denitrified swine effluent in a batch electrochemical system.

There is high interest in the recovery of phosphorus (P) from wastewater through crystallization processes. However, the addition of chemical reagents (e.g., sodium hydroxide) to raise the pH may result in high treatment costs and increased concentrations of undesired metal ions (e.g., sodium). As an alternative, in this research we considered electrochemical mediated precipitation at low current densities (0.4-1.2 A m-2) without using chemical reagents. For that purpose, a two-chamber electrochemical system was operated in batch for treating denitrified swine effluent (48 mg P L-1). By applying current at 1.2 A m-2, and targeting pH 11.5, a maximum P removal rate of 33.4 mmol P (L·d-1) was obtained while the P removal efficiency was above 90 %. New solids that formed mostly remained suspended in the catholyte. Before discharge, the catholyte effluent was recirculated to the anodic compartment to neutralize the pH, achieving a final pH of 6.4 ± 0.1. Chlorine (Cl2) production in the anodic compartment was favored by a small anode surface and a high initial pH of the catholyte. Although the production of chlorine achieved was limited (the highest concentration was 8.6 ± 0.1 mg Cl2 L-1) these findings represent a new opportunity for the recovery and onsite use of this side-product. Electrochemical impedance spectroscopy tests confirmed that the deposition of solids inside the cathodic compartment during the experimental period was limited. Membrane analysis revealed significant scaling of carbonate compounds. The electrochemical treatment described above was shown as a promising alternative to sodium hydroxide and sulfuric acid dosage for pH adjustment when crystallizing phosphate salts.

Development and evaluation of two rapid lateral flow assays for on-site detection of African swine fever virus.

Introduction: African swine fever (ASF) is a lethal and highly contagious transboundary animal disease with the potential for rapid international spread. In the absence of a widely available and definitively proven vaccine, rapid and early detection is critical for ASF control. The quick and user-friendly lateral flow assay (LFA) can easily be performed by following simple instructions and is ideal for on-site use. This study describes the development and validation of two LFAs for the rapid detection of ASF virus (ASFV) in pig serum. Methods: The highly immunogenic antigens (p30 and p72) of ASFV Georgia 2007/1 (genotype II) were expressed in plants (Nicotiana benthamiana) and were used to immunize BALB/c mice to generate specific monoclonal antibodies (mAbs) against the p30 and p72 proteins. mAbs with the strongest binding ability to each protein were used to develop p30_LFA and p72_LFA for detecting the respective ASFV antigens. The assays were first evaluated using a spike-in test by adding the purified p30 or p72 protein to a serum sample from a healthy donor pig. Further validation of the tests was carried out using serum samples derived from experimentally infected domestic pigs, field domestic pigs, and feral pigs, and the results were compared with those of ASFV real-time PCR. Results: p30_LFA and p72_LFA showed no cross-reaction with common swine viruses and delivered visual results in 15 min. When testing with serially diluted proteins in swine serum samples, analytical sensitivity reached 10 ng/test for p30_LFA and 20 ng/test for p72_LFA. Using real-time PCR as a reference, both assays demonstrated high sensitivity (84.21% for p30_LFA and 100% for p72_LFA) with experimentally ASFV-infected pig sera. Specificity was 100% for both LFAs using a panel of PBS-inoculated domestic pig sera. Excellent specificity was also shown for field domestic pig sera (100% for p30_LFA and 93% for p72_LFA) and feral pig sera (100% for both LFAs). Conclusion: The results obtained in this study suggest that p30_LFA and p72_LFA hold promise as rapid, sensitive, user-friendly, and field-deployable tools for ASF control, particularly in settings with limited laboratory resources.

Production and concentration of keratinases and application of fermentation residual in removing hexavalent chromium.

The production of keratinases was evaluated in submerged fermentation with Aspergillus niger and by pigs' swine hair in a batch bioreactor. Experimental planning was performed to assess the interaction between different variables. The enzyme extract produced was characterized at various pH and temperatures and subjected to enzyme concentration using a biphasic aqueous system and salt/solvent precipitation techniques. In addition, the substrate's potential in reducing hexavalent chromium from synthetic potassium dichromate effluent with an initial concentration of 20 mg L-1 of chromium was evaluated. The resulting enzyme extract showed 89 ± 2 U mL-1 of keratinase. The enzyme concentration resulted in a purification factor of 1.3, while sodium chloride/acetone and ammonium sulfate/acetone resulted in a purification factor of 1.9 and 1.4, respectively. Still using the residual substrate of swine hair from the fermentation, a 94% reduction of hexavalent chromium concentration occurred after 9 h of reaction. Thus, the study proved relevant for producing keratinases, with further environmental applicability and the possibility of concentrating the extract via low-cost processes.

Navigating the threat of African swine fever: a comprehensive review.

African swine fever (ASF) is caused by Asfivirus and has become one of the most important diseases of swine in recent years. ASF was an endemic disease of the sub-Saharan Africa but later spread to various parts of the world. The infection in ticks and wild swine, alongside global pork trade, drives its spread and persistence. Once introduced to an area, the disease is difficult to eliminate due to sylvatic, domestic, and tick-swine transmission cycles. Because of the existence of various modes of transmission of the ASF virus, biosecurity measures have not been very successful. The line of treatment is not of much use and the outcome of this disease is usually fatal. The prognosis or the recovery of the animal depends on the virulence of the strain involved. Development of vaccines has been attempted but to date has not been very successful. This review focuses on the basic context of ASF, the challenges associated with it, and the options that might be available to prevent its occurrence which includes the different vaccine development strategies tried and tested till now.