Efficacy of PCV2 Vaccination Under Natural Conditions: A Longitudinal Study Using PCR and Virus Isolation

Porcine circovirus type 2 (PCV2) is the main cause of porcine circovirus-associated disease (PCVAD). Despite the widespread use of anti-PCV2 vaccines, their efficacy varies, influenced by co-infection and evaluation methods. This study assessed the efficacy of Ingelvac CircoFLEX® PCV2 vaccine under natural conditions. One hundred serum samples were collected from vaccinated and non-vaccinated piglets aged 21 to 173 days. PCR and antibody positivity rates did not show significant differences between the two groups, but PCV2 gene load at 91 days was significantly lower (p = 0.0095) in the vaccinated group. Anti-PCV2 antibody titers were also significantly lower in the vaccinated group at 91, 145, and 173 days (p < 0.0001). PCV2 was isolated from 50% of piglets in the non-vaccinated group (50%), compared with none (0%) in the vaccinated group, suggesting that PCV2 gene load in the non-vaccinated group did not correlate with viremia. Both groups were positive for antibodies to porcine reproductive and respiratory syndrome virus (PRRSV) at 63 days, prior to the surge in PCV2 gene load, suggesting PRRSV may enhance PCV2 replication. These findings highlight that while the vaccine reduced PCVAD damage, evaluation should incorporate methods such as virus isolation instead of relying solely on PCR

Conserved Functions of Orthohepadnavirus X Proteins to Inhibit Type-I Interferon Signaling

Orthohepadnavirus causes chronic hepatitis in a broad range of mammals, including primates, cats, woodchucks, and bats. Hepatitis B virus (HBV) X protein inhibits type-I interferon (IFN) signaling, thereby promoting HBV escape from the human innate immune system and establishing persistent infection. However, whether X proteins of Orthohepadnavirus viruses in other species display a similar inhibitory activity remains unknown. Here, we investigated the anti-IFN activity of 17 Orthohepadnavirus X proteins derived from various hosts. We observed conserved activity of Orthohepadnavirus X proteins in inhibiting TIR-domain-containing adaptor protein inducing IFN-β (TRIF)-mediated IFN-β signaling pathway through TRIF degradation. X proteins from domestic cat hepadnavirus (DCH), a novel member of Orthohepadnavirus, inhibited mitochondrial antiviral signaling protein (MAVS)-mediated IFNβ signaling pathway comparable with HBV X. These results indicate that inhibition of IFN signaling is conserved in Orthohepadnavirus X proteins.Citation: Choonnasard, A.; Shofa, M.; Okabayashi, T.; Saito, A. Conserved Functions of Orthohepadnavirus X Proteins to Inhibit Type-I Interferon Signaling. Int. J. Mol. Sci. 2024, 25, 3753. https://doi.org/10.3390/ijms2507375

Conserved Antagonization of Type I Interferon Signaling by Arterivirus GP5 Proteins

Arteriviruses can establish persistent infections in animals such as equids, pigs, nonhuman primates, rodents, and possums. Some Arteriviruses can even cause overt and severe diseases such as Equine Arteritis in horses and Porcine Reproductive and Respiratory Syndrome in pigs, leading to huge economic losses. Arteriviruses have evolved viral proteins to antagonize the host cell’s innate immune responses by inhibiting type I interferon (IFN) signaling, assisting viral evasion and persistent infection. So far, the role of the Arterivirus glycoprotein 5 (GP5) protein in IFN signaling inhibition remains unclear. Here, we investigated the inhibitory activity of 47 Arterivirus GP5 proteins derived from various hosts. We demonstrated that all GP5 proteins showed conserved activity for antagonizing TIR-domain-containing adapter proteins inducing interferon-β (TRIF)-mediated IFN-β signaling through TRIF degradation. In addition, Arterivirus GP5 proteins showed a conserved inhibitory activity against IFN-β signaling, induced by either pig or human TRIF. Furthermore, certain Arterivirus GP5 proteins could inhibit the induction of IFN-stimulated genes. These findings highlight the role of Arterivirus GP5 proteins in supporting persistent infection.Citation: Ringo, R.S.; Choonnasard, A.; Okabayashi, T.; Saito, A. Conserved Antagonization of Type I Interferon Signaling by Arterivirus GP5 Proteins. Viruses 2024, 16, 1240. https://doi.org/10.3390/v1608124

Indonesian Herb Extracts Inhibit the Replication of Bovine Respiratory Syncytial Virus: In Vitro Study

Bovine respiratory syncytial virus (BRSV) is highly prevalent in cattle. It is a major viral cause of bovine respiratory disease complex, which is associated with morbidity, mortality and substantial economic impact. Currently available treatments are only symptomatic, but no specific treatments are available for BRSV infection. This study aimed to identify new antiviral agents against BRSV, which could be used to control bovine respiratory disease complex in cattle with Indonesian herb extracts. Ethanol extracts prepared from Indonesian herbs including Andrographis paniculata, Phyllanthus niruri, Curcuma aeruginosa, and Curcuma xanthorrhiza were evaluated for anti-BRSV activity in A549 cells. The cytotoxicity of the herb extracts was evaluated using a CCK-8 cell viability assay. Antiviral activities of the herb extracts were examined using cell activity and cytopathic assays. The effect on virus production was evaluated by qRT-PCR and plaque-formation assays. Extracts of Curcuma xanthorrhiza (125 μg/ml), Andrographis paniculata (250 μg/ml), and Phyllanthus niruri (62.5 μg/ml) inhibited BRSV activity in A549 in pre-, simultaneously-, and post-infection treatment assays, respectively, as measured by the selective index. Reduction of BRSV activities by the herb extracts correlated with inhibition of viral gene expression and inhibition of plaque formation in a concentration- and time-dependent manner. Our findings suggest that these herb extracts have sufficient potency to be used not only as a therapeutic agent but also as a preventive agent to limit BRSV infection

SFTSV utilizes AXL/GAS6 for entry via PI3K-PLC-dependent macropinocytosis activated by AXL-kinase

Severe fever with thrombocytopenia syndrome (SFTS) is a significant public health concern caused by SFTS virus (SFTSV), a tick-borne RNA virus. Previous studies have identified DC-SIGN and related C-type lectins as receptors of SFTSV infection in specific cell populations. Our genome-wide CRISPR activation screening identified AXL, a receptor tyrosine kinase, as a novel entry receptor for SFTSV. We found that AXL-mediated SFTSV infection utilizes the bridging action of growth arrest-specific protein 6 between AXL and phosphatidylserine on virus particles. This interaction induces autophosphorylation of tyrosine residues in the intracellular domain of AXL, recruiting phosphatidylinositol-3 kinase (PI3K) and phospholipase C (PLC) and establishing a macropinocytotic pathway of SFTSV entry. The AXL-PI3K-PLC-dependent entry pathway was observed in diverse cell types, including human umbilical vein endothelial cells (HUVEC), offering deep insights into the lifecycle of SFTSV and offering AXL as a novel therapeutic target against SFTS.IMPORTANCEUnderstanding the molecular mechanisms of viral entry is critical for developing targeted antiviral therapies since there is no effective vaccine or antiviral drug against severe fever with thrombocytopenia syndrome (SFTS). This study uncovered AXL as a potential entry receptor for SFTS virus (SFTSV) via PI3K/PLC-dependent macropinocytosis pathway distinct from previously reported viral entry mechanism. The inhibition of these cellular enzymes resulted in the suppression of SFTSV infection in the AXL-expressing cell lines and HUVEC. Our research sheds light on the intricate molecular mechanisms underlying these interactions by utilizing mutants of AXL and represents a promising target for the development of innovative therapeutics against SFTS

Highly polymerized proanthocyanidins (PAC) components from blueberry leaf and stem significantly inhibit SARS-CoV-2 infection via inhibition of ACE2 and viral 3CLpro enzymes

With the current worldwide pandemic of COVID-19, there is an urgent need to develop effective treatment and prevention methods against SARS-CoV-2 infection. We have previously reported that the proanthocyanidin （PAC） fraction in blueberry （BB） leaves has strong antiviral activity against hepatitis C virus （HCV） and human T-lymphocytic leukemia virus type 1 （HTLV-1）. In this study, we used Kunisato 35 Gou （K35） derived from the rabbit eye blueberry （Vaccinium virgatum Aiton）, which has a high PAC content in the leaves and stems. The mean of polymerization （mDP） of PAC in K35 was the highest of 7.88 in Fraction 8 （Fr8） from the stems and 12.28 of Fraction 7 （Fr7） in the leaves. The composition of BB-PAC in K35 is that most are B-type bonds with a small number of A-type bonds and cinchonain I as extension units. A strong antiviral effect was observed in Fr7, with a high polymerized PAC content in both the leaves and stems. Furthermore, when we examined the difference in the action of BB-PAC before and after SARS-CoV-2 infection, we found a stronger inhibitory effect in the pre-infection period. Moreover, BB-PAC Fr7 inhibited the activity of angiotensin II converting enzyme （ACE2）, although no effect was observed in a neutralization test of pseudotyped SARS-CoV-2. The viral chymotrypsin-like cysteine protease （3CLpro） of SARS-CoV-2 was also inhibited by BB-PAC Fr7 in leaves and stems. These results indicate that BB-PAC has at least two different inhibitory effects, and that it is effective in suppressing SARS-CoV-2 infection regardless of the time of infection

Genotyping of swine Mycobacterium avium subsp. hominissuis isolates from Kyushu, Japan

The incidence of diseases caused by nontuberculous mycobacteria (NTM) is increasing annually worldwide, including Japan. Mycobacterium avium subsp. hoiminissuis (MAH) is one of the most common NTM species responsible for chronic lung diseases in animals and humans. In the current study, mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) typing was employed to characterize the genetic diversity of swine MAH isolates from Kyushu, Japan. In total, 309 isolates were obtained from the lymph nodes of 107 pigs not displaying any clinical signs of disease, of which 307 were identified as MAH, comprising 173 strains. Based on eight established MIRU-VNTR loci, the MAH strains represented 50 genotypes constituting three lineages, and 29 had not been described in the Mac French National Institute for Agricultural Research Nouzilly MIRU-VNTR (Mac-INMV) database. MAH was the dominant M. avium complex (MAC) in pigs from Kyushu, and there was high genetic diversity among genotype profiles of MAH from Kyushu. We identified three predominant genotype profiles in the tested area sharing high relatedness with genotype profiles of strains isolated in European countries. MAH was the most common NTM in pigs from Kyushu and exhibited high diversity, with new strain-derived genotypes.Citation: Mawar SUBANGKIT, Tomoki YAMAMOTO, Mikiko ISHIDA, Arisa NOMURA, Natsu YASIKI, Putu Eka SUDARYATMA, Yoshitaka GOTO, Tamaki OKABAYASHI, Genotyping of swine Mycobacterium avium subsp. hominissuis isolates from Kyushu, Japan, Journal of Veterinary Medical Science, 2019, 81 巻, 8 号, p. 1074-1079, 公開日 2019/08/09, Online ISSN 1347-7439, Print ISSN 0916-7250, https://doi.org/10.1292/jvms.19-004

Complete genome sequence of the avian paramyxovirus serotype 9 strain duck/Miyazaki/128/2021

Here, we report the complete genome sequence of the avian paramyxovirus serotype 9 strain duck/Miyazaki/128/2021, which was determined using the Illumina MiSeq platform. The position of the hemagglutinin-neuraminidase stop codon differed from that of the only other available completely sequenced prototype strain, duck/New York/22/1977.Citation: Hirohisa Mekata, Mari Yamamoto, Yuto Matsui, Ahmad Massoud Niazi, Kentaro Yamada, Tamaki Okabayashi, Se-Yeoun Cha, Hyung-Kwan Jang, Complete genome sequence of the avian paramyxovirus serotype 9 strain duck/Miyazaki/128/2021, Microbiology Resource Announcements, 13(11), 2024-11-12, https://doi.org/10.1128/mra.00060-2

Urine of Cats with Severe Fever with Thrombocytopenia Syndrome: A Potential Source of Infection Transmission

Severe fever with thrombocytopenia syndrome (SFTS), caused by infection with the SFTS virus, is an emerging fatal tick-borne zoonosis endemic to East Asia. Although SFTS is a tick-borne disease, the virus can be transmitted from animals with SFTS without a tick bite. Direct transmission of the SFTS virus from animals to humans has been reported; however, the transmission route is unclear in some cases. Therefore, this study focused on the possibility of SFTS virus transmission through urine and attempted to isolate the infectious virus from the urine of animals with SFTS. Since more efficient cell isolation is needed to determine whether the SFTS virus is present, we first expressed dendritic cell-specific ICAM-3-grabbing nonintegrin (DC-SIGN), the major receptor for the virus, in Vero cells (Vero-DC-SIGN cells) using a retroviral vector. When inoculated with equal amounts of the SFTS virus strain and SFTS-virus-infected animal serum, Vero-DC-SIGN cells had 42–136% and 20–85% more foci, respectively, than their parent Vero cells. After confirming that Vero-DC-SIGN cells were more suitable for the isolation of the SFTS virus, we investigated whether it could be isolated from the urine of eight cats and two dogs with SFTS. The virus was isolated from 25 μL of urine from two cats with SFTS. Considering that cats excrete 50–100 mL of urine per day, the transmission of the SFTS virus via the urine of cats with SFTS cannot be ruled out. Individuals examining or caring for cats suspected of having SFTS should be aware of the possibility of viral transmission via urine

Seroprevalence of severe fever with thrombocytopenia syndrome virus in medium-sized wild mammals in Miyazaki, Japan.

application/pdfSevere fever with thrombocytopenia syndrome （SFTS） is a fatal emerging tick-borne zoonotic disease caused by the SFTS virus （SFTSV）. SFTSV infection in humans and companion animals is a matter of concern in endemic areas. Various wild animals are involved in the transmission cycle of SFTSV with vector ticks. Because the home range of medium-sized wild mammals commonly overlaps with humans' living spheres, this study aimed to reveal the endemicity of SFTSV in such mammals. This study investigated the prevalence of antibodies against SFTSV and viral RNA in medium-sized wild mammals in Miyazaki Prefecture, Japan where human cases have been most frequently reported in Japan and performed a phylogenetic analysis to compare the detected SFTSV with those previously reported. Forty-three of 63 （68%） Japanese badgers （Meles anakuma） and 12 of 53 （23%） Japanese raccoon dogs （Nyctereutes procyonoides viverrinus） had antibodies against SFTSV. Japanese marten （n = 1）, weasels （n = 4）, and Japanese red fox （n = 1） were negative. Two of 63 （3%） badgers tested positive for SFTSV RNA, whereas the other species were negative. Phylogenetic analysis of the partial nucleotide sequence of SFTSV revealed that viral RNA detected from badgers exhibited 99.8% to 100% similarity to SFTSV, as previously reported in humans, cat, and ticks in the study area. This study demonstrated high seropositivity of antibodies in medium-sized wild mammals and suggested that SFTSV could be shared among these mammals, humans, and companion animals in endemic areas