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Abstract This study aimed to evaluate the efficacy of Lactiplantibacillus argentoratensis AGMB00912 (LA) in reducing Salmonella Typhimurium infection in weaned piglets. The investigation focused on the influence of LA on the gut microbiota composition, growth performance, and Salmonella fecal shedding. The results indicated that LA supplementation significantly improved average daily gain and reduced the prevalence and severity of diarrhea. Fecal analysis revealed reduced Salmonella shedding in the LA-supplemented group. Furthermore, LA notably altered the composition of the gut microbiota, increasing the levels of beneficial Bacillus and decreasing those of harmful Proteobacteria and Spirochaetes. Histopathological examination showed less intestinal damage in LA-treated piglets than in the controls. The study also observed that LA affected metabolic functions related to carbohydrate, amino acid, and fatty acid metabolism, thereby enhancing gut health and resilience against infection. Short-chain fatty acid concentrations in the feces were higher in the LA group, suggesting improved gut microbial activity. LA supplementation enriched the population of beneficial bacteria, including Streptococcus, Clostridium, and Bifidobacterium, while reducing the number of harmful bacteria, such as Escherichia and Campylobacter. These findings indicate the potential of LA as a probiotic alternative for swine nutrition, offering protective effects to the gut microbiota against Salmonella infection.

Abstract Background Infectious diseases transmitted by wild animals are major threats to public health. This study aimed to investigate the potential of rescued wild animals that died of unknown causes as reservoirs of infectious agents. From 2018 to 2019, 121 dead wild animals (55 birds and 66 mammals) were included in this study. All wild animals died during treatment after anthropogenic events. After deaths of animals, necropsies were performed and trachea, lungs, large intestine (including stool), and spleen were collected to determine causes of deaths. A high-throughput screening (HTS) quantitative polymerase chain reaction (qPCR) designed to detect 19 pathogens simultaneously against 48 samples in duplicate was performed using nucleic acids extracted from pooled tissues and peripheral blood samples. If positive, singleplex real-time PCR was performed for individual organs or blood samples. Results The HTS qPCR showed positive results for Campylobacter jejuni (10/121, 8.3%), Campylobacter coli (1/121, 0.8%), Mycoplasma spp. (78/121, 64.5%), and Plasmodium spp. (7/121, 5.7%). Singleplex real-time PCR confirmed that C. jejuni was detected in the large intestine but not in the blood. C. coli was only detected in the large intestine. Mycoplasma spp. were detected in all organs, having the highest proportion in the large intestine and lowest in the blood. Plasmodium spp. was also detected in all organs, with proportions being were similar among organs. Conclusions This study shows that wild animals can become carriers of infectious agents without showing any clinical symptoms.

Recently, neurological diseases associated with astroviruses (AstVs) have been reported in pigs, ruminants, minks, and humans. In 2017, neuro-invasive porcine astrovirus (Ni-PAstV) 3 was detected in the central nervous system (CNS) of pigs with encephalomyelitis in Hungary and the USA. In the process of diagnosing domestic pigs exhibiting neurological signs, histopathologic lesions of non-suppurative encephalomyelitis with meningitis, neuronal vacuolation, and gliosis were detected, and PAstV was identified using reverse transcriptase PCR in CNS samples of four pigs in three farms from August to September in 2020, South Korea. Subsequently, the ORF2 region was successfully acquired from three brain samples, facilitating subsequent analysis. Four genotypes of PAstV (PAstV1, 3, 4, and 5) were detected, and coinfection of PAstV with multiple genotypes was observed in brain samples. This is the first study to report Ni-PAstV infection in pigs in South Korea.

Abstract Background Porcine circovirus, a non‐enveloped single‐stranded DNA virus belonging to the genus Circovirus of the family Circoviridae, is a major pathogen of porcine circovirus‐associated disease. Porcine circovirus 3, a novel porcine circovirus, has been identified in individuals with clinical symptoms. Objectives The prevalence of porcine circovirus 2 and porcine circovirus 3 and the confirmation of diagnosis of this emerging viral disease have not been fully studied yet. Therefore, the objective of the present study was to investigate the prevalence of porcine circovirus 2 and porcine circovirus 3 in slaughtered pigs and wild boars in Korea between 2018 and 2019. Methods Lungs and hilar lymph nodes of healthy pigs slaughtered in slaughterhouses and captured wild pigs were collected, and viruses were detected by multiplex quantitative polymerase chain reaction and two staining methods (in situ hybridization and immunohistochemistry) to confirm the presence of porcine circovirus 2 and porcine circovirus 3. Results Positive rates of porcine circovirus 2 in lungs and hilar lymph nodes were 78.1% (75/96) and 89.5% (86/96) in slaughtered pigs, respectively. They were 18.0% (30/167) and 46.3% (24/55) in wild boars, respectively. Positive rates of porcine circovirus 3 in lungs and hilar lymph nodes were 30.2% (29/96) and 13.5% (13/96) in slaughtered pigs, respectively. They were 4.2% (7/167) and 5.5% (3/55) in wild boars, respectively. At the farm level, positive rates of porcine circovirus 2 and porcine circovirus 3 were 97.9% (47/48) and 54.2% (26/48), respectively. Positive rates of porcine circovirus 2 and porcine circovirus 3 decreased in spring. Immunohistochemistry and in situ hybridization confirmed the presence of porcine circovirus 2 and porcine circovirus 3 in lungs, but not porcine circovirus 3 in the hilar lymph nodes. Conclusion These results suggest that the prevalence of porcine circovirus 2 and porcine circovirus 3 might vary depending on the season and the type of sample. Wild boars might play a role in the epidemiology of porcine circovirus 2 and porcine circovirus 3 in South Korea. Continuous surveillance and further study are needed for this emerging disease.

Severe fever with thrombocytopenia syndrome (SFTS), a tick-borne zoonotic disease, is caused by infection with SFTS virus (SFTSV). A previous study reported that human-to-human direct transmission of SFTSV can occur. However, potential animal-to-animal transmission of SFTSV without ticks has not been fully clarified. Thus, the objective of this study was to investigate potential mice-to-mice transmission of SFTSV by co-housing three groups of mice [i.e., wild-type mice (WT), mice injected with an anti-type I interferon-α receptor-blocking antibody (IFNAR Ab), and mice with knockout of type I interferon-α receptor (IFNAR KO)] as spreaders or recipients with different immune competence. As a result, co-housed IFNAR Ab and IFNAR KO mice showed body weight loss with SFTS viral antigens detected in their sera, extracorporeal secretions, and various organs. Based on histopathology, white pulp atrophy in the spleen was observed in all co-housed mice except WT mice. These results obviously show that IFNAR Ab and IFNAR KO mice, as spreaders, exhibited higher transmissibility to co-housed mice than WT mice. Moreover, IFNAR KO mice, as recipients, were more susceptible to SFTSV infection than WT mice. These findings suggest that type I interferon signaling is a pivotal factor in mice intraspecies transmissibility of SFTSV in the absence of vectors such as ticks.

IntroductionBovine herpesvirus 4 (BoHV-4) is a bovine Rhadinovirus not associated with a specific pathological lesion or disease and experimentally employed as a viral vector vaccine. BoHV-4-based vector (BoHV-4-BV) has been shown to be effective in immunizing and protecting several animal species when systemically administrated through intramuscular, subcutaneous, intravenous, or intraperitoneal routes. However, whether BoHV-4-BV affords respiratory disease protection when administered intranasally has never been tested.MethodsIn the present study, recombinant BoHV-4, BoHV-4-A-S-ΔRS-HA-ΔTK, was constructed to deliver an expression cassette for the SARS-CoV-2 spike glycoprotein, and its immunogenicity, as well as its capability to transduce cells of the respiratory tract, were tested in mice. The well-established COVID-19/Syrian hamster model was adopted to test the efficacy of intranasally administered BoHV-4-A-S-ΔRS-HA-ΔTK in protecting against a SARS-CoV-2 challenge.ResultsThe intranasal administration of BoHV-4-A-S-ΔRS-HA-ΔTK elicited protection against SARS-CoV-2, with improved clinical signs, including significant reductions in body weight loss, significant reductions in viral load in the trachea and lungs, and significant reductions in histopathologic lung lesions compared to BoHV-4-A-S-ΔRS-HA-ΔTK administered intramuscularly.DiscussionThese results suggested that intranasal immunization with BoHV-4-BV induced protective immunity and that BoHV-4-BV could be a potential vaccine platform for the protection of other animal species against respiratory diseases.

Currently, there are no commercial vaccines or therapeutics against severe fever with thrombocytopenia syndrome (SFTS) virus. This study explored an engineered Salmonella as a vaccine carrier to deliver a eukaryotic self-mRNA replicating vector, pJHL204. This vector expresses multiple SFTS virus antigenic genes for the nucleocapsid protein (NP), glycoprotein precursor (Gn/Gc), and nonstructural protein (NS) to induce host immune responses. The engineered constructs were designed and validated through 3D structure modeling. Western blot and qRT-PCR analyses of transformed HEK293T cells confirmed the delivery and expression of the vaccine antigens. Significantly, mice immunized with these constructs demonstrated a cell-mediated and humoral response as balanced Th1/Th2 immunity. The JOL2424 and JOL2425 delivering NP and Gn/Gc generated strong immunoglobulin IgG and IgM antibodies and high neutralizing titers. To further examine the immunogenicity and protection, we utilized a human DC-SIGN receptor transduced mouse model for SFTS virus infection by an adeno-associated viral vector system. Among the SFTSV antigen constructs, the construct with full-length NP and Gn/Gc and the construct with NP and selected Gn/Gc epitopes induced robust cellular and humoral immune responses. These were followed by adequate protection based on viral titer reduction and reduced histopathological lesions in the spleen and liver. In conclusion, these data indicate that recombinant attenuated Salmonella JOL2424 and JOL2425 delivering NP and Gn/Gc antigens of SFTSV are promising vaccine candidates that induce strong humoral and cellular immune responses and protection against SFTSV. Moreover, the data proved that the hDC-SIGN transduced mice as a worthy tool for immunogenicity study for SFTSV.

A mouse model of SARS-CoV-2 that can be developed in any molecular biology lab with standard facilities will be valuable in evaluating drugs and vaccines. Here we present a simplified SARS-CoV-2 mouse model exploiting the rapid adenoviral purification method. Mice that are sensitive to SARS-CoV-2 infection were generated by transducing human angiotensin-converting enzyme 2 (hACE2) by an adenovirus. The expression kinetics of the hACE2 in transduced mice were assessed by immunohistochemistry, RT-PCR, and qPCR. Further, the ability of the hACE2 to support viral replication was determined in vitro and in vivo. The hACE2 expression in the lungs of mice was observed for at least nine days after transduction. The murine macrophages expressing hACE2 supported viral replication with detection of high viral titers. Next, in vivo studies were carried out to determine viral replication and lung disease following SARS-CoV-2 challenge. The model supported viral replication, and the challenged mouse developed lung disease characteristic of moderate interstitial pneumonia. Further, we illustrated the utility of the system by demonstrating protection using an oral mRNA vaccine. The multicistronic vaccine design enabled by the viral self-cleaving peptides targets receptor binding domain (RBD), heptad repeat domain (HR), membrane glycoprotein (M) and epitopes of nsp13 of parental SARS-CoV-2. Further, Salmonella and Semliki Forest virus replicon were exploited, respectively, for gene delivery and mRNA expression. We recorded potent cross-protective neutralizing antibodies in immunized mice against the SARS-CoV-2 delta variant. The vaccine protected the mice against viral replication and SARS-CoV-2-induced weight loss and lung pathology. The findings support the suitability of the model for preclinical evaluation of anti-SARS-CoV-2 therapies and vaccines. In addition, the findings provide novel insights into mRNA vaccine design against infectious diseases not limiting to SARS-CoV-2.

OBJECTIVE: To determine pulmonary anthracosis in zoo, wildlife, and companion animals of Jeollabuk-do Province, South Korea. ANIMALS: A total of 350 animals of 61 different species, belonging to 3 classes (mammals: n = 38; avian: 21; and reptiles: 2) from different habitats in Jeollabuk-do Province, were examined. PROCEDURES: Gross lung examination and tissue sampling were done at postmortem, and histopathological analysis was microscopically done on hematoxylin and eosin-stained slides. RESULTS: Macroscopic analysis of anthracotic lung tissue revealed minute (pinpoint size) spots and black pigmentation in a scattered and/or coalescing fashion. The presence of carbon particles was noted in 154 (44%, 154/350) cases. Based on habitation, zoo animals had the highest frequency of anthracosis in the lung (55.2%, 69/125), followed by companion animals (45.2%, 56/124) and wildlife animals (28.7%, 29/101). There was an association between habitation and the presence of anthracosis (P < .05). CLINICAL RELEVANCE: This study revealed evidence that the presence of anthracosis is associated with the environmental air quality of zoo, wildlife, and companion animals in Jeollabuk-do Province, South Korea. Air pollution may affect the respiratory health of the endangered species at the Jeonju Zoo as well as the human population. Continuous monitoring of particulate matter and establishing policies that control industrialization around the province would enable quick action to curb any potential respiratory health risks to animals kept in the urban cities of the province. [ABSTRACT FROM AUTHOR]