Characterization and arbovirus susceptibility of cultured CERNI cells derived from sika deer (Cervus nippon).

Cervus nippon (sika deer) are widely distributed throughout eastern Asia. Deer possess a variety of antibodies against several zoonotic pathogens, indicating that they act as reservoir of zoonoses. In this study, we reported the characterization of cultured cells derived from sika deer and evaluated their susceptibility to arthropod-borne viruses to clarify their usefulness in virological studies. Cells derived from testicular tissue in Dulbecco's modified eagle medium with 16% fetal bovine serum started growing as primary cultured cells. The diploid cells consisted of 68 chromosomes, consistent with those of Japanese sika deer previously reported. The phylogenetic analysis showed the cells formed a robust clade with Japanese population of C. nippon, indicating that the cultured cells established in this study were originated from the Japanese sika deer. The cells immortalized by the simian virus 40 T-antigen were predominantly spindle-shaped cells exhibiting adhesive properties, and cultivated at 37°C and 5% CO2, which are common culture conditions for many mammalian cell lines. Western blotting analysis indicated that the cultured cells were multiple types of cells that coexist, including at least epithelial, fibroblast, and also Leydig cells. We confirmed that the cells have susceptibility to several arboviruses distributed in Japan: Getah virus, Japanese encephalitis virus, Oz virus, and severe fever with thrombocytopenia syndrome virus, but not to Tarumiz tick virus. From these results, the cells contribute to clarify the role of sika deer as a reservoir of zoonoses in nature and deer-associated experimental research at the cellular and molecular levels.

Promoting Biological Similarity by Collagen Microfibers in 3D Colorectal Cancer-Stromal Tissue: Replicating Mechanical Properties and Cancer Stem Cell Markers.

The extracellular matrix (ECM) of cancer tissues is rich in dense collagen, contributing to the stiffening of these tissues. Increased stiffness has been reported to promote cancer cell proliferation, invasion, metastasis, and prevent drug delivery. Replicating the structure and mechanical properties of cancer tissue in vitro is essential for developing cancer treatment drugs that target these properties. In this study, we recreated specific characteristics of cancer tissue, such as collagen density and high elastic modulus, using a colorectal cancer cell line as a model. Using our original material, collagen microfibers (CMFs), and a constructed three-dimensional (3D) cancer-stromal tissue model, we successfully reproduced an ECM highly similar to in vivo conditions. Furthermore, our research demonstrated that cancer stem cell markers expressed in the 3D cancer-stromal tissue model more closely mimic in vivo conditions than traditional two-dimensional cell cultures. We also found that CMFs might affect an impact on how cancer cells express these markers. Our 3D CMF-based model holds promise for enhancing our understanding of colorectal cancer and advancing therapeutic approaches. STATEMENT OF SIGNIFICANCE: Reproducing the collagen content and stiffness of cancer tissue is crucial in comprehending the properties of cancer and advancing anticancer drug development. Nonetheless, the use of collagen as a scaffold material has posed challenges due to its poor solubility, hindering the replication of a cancer microenvironment. In this study, we have successfully recreated cancer tissue-specific characteristics such as collagen density, stiffness, and the expression of cancer stem cell markers in three-dimensional (3D) colorectal cancer stromal tissue, utilizing a proprietary material known as collagen microfiber (CMF). CMF proves to be an ideal scaffold material for replicating cancer stromal tissue, and these 3D tissues constructed with CMFs hold promise in contributing to our understanding of cancer and the development of therapeutic drugs.

Establishment of a histiocytic sarcoma cell line and anti-tumor effect of bortezomib in the African pygmy hedgehog (Atelerix albiventris).

The African pygmy hedgehog (Atelerix albiventris) is known to have a high incidence of tumor. However, investigating the tumors of this species has been constrained by the limited availability of research materials such as cell lines and genome information. In this study, we successfully established a novel cell line from a histiocytic sarcoma (HS) of an African pygmy hedgehog, allowing us to conduct a drug screening. We investigated using FDA-approved drug library screening to determine which anticancer drug this tumor cell line is sensitive to, and as a result of apoptosis experiments, bortezomib among the three proteasome inhibitors was found to induce cell death of cancer cells by significantly increasing caspase-3 cleavage (P<0.01). Thus, we elucidated that the proteasome inhibitors, particularly bortezomib, exhibit anti-tumor effects on a cell line derived from an HS in an African pygmy hedgehog through a mechanism comparable to that described in human tumors. This study reports the first characterized cell line from the African pygmy hedgehog and also highlights the potential utility of bortezomib as an anti-tumor treatment for HS in this species.

Hypoglycemic effects of mountain caviar extract and inhibitory mechanism of saponins, including momordin Ic, on glucose absorption.

Mountain caviar is a fruit of Kochia scoparia that contains momordin Ic as a major saponin constituent. Its extract (MCE) has been shown to suppress blood glucose elevations in the human oral glucose tolerance test (OGTT) as well as increases in blood glucose in OGTT, gastric emptying (GE), and glucose incorporation in the small intestine in rats. However, the effects of MCE and momordin Ic on glucose absorption in mice and these action mechanisms have not been examined for more than 2 decades. Therefore, we herein investigated the effects of MCE, its saponin fraction, and momordin Ic on blood glucose elevations in mice. Mouse blood glucose elevation tests were performed on carbohydrate-loaded mice. The mountain caviar saponin fraction significantly delayed blood glucose elevations in glucose-, sucrose-, and soluble starch-loaded mice. In glucose-loaded mice, the saponin fraction, MCE, and momordin Ic significantly suppressed rapid glucose elevations after glucose loading, but not sucrose loading. A mouse GE study was performed by loading with glucose and phenolphthalein solution. Momordin Ic and MCE strongly suppressed mouse GE. Intestinal glucose absorption was evaluated by the incorporation of 2-deoxyglucose (2-DG) into Caco-2 cell layers and mouse duodenum wall vesicles. The results obtained showed that momordin Ic inhibited the incorporation of 2-DG into Caco-2 cells and mouse duodenum vesicles. Collectively, these results suggest that MCE, particularly the principal saponin, momordin Ic, preferably suppressed glucose-induced blood glucose elevations and delayed carbohydrate-induced glucose elevations in mice. The underlying mechanism was found to involve the suppression of GE and intestinal glucose absorption.

Gn protein expressed in plants for diagnosis of severe fever with thrombocytopenia syndrome virus.

Severe fever with thrombocytopenia syndrome virus (SFTSV) causes the highly fatal disease in humans. To facilitate diagnosis, the native form of subunit glycoprotein (Gn), a prime target for potential vaccines and therapies, was produced in Nicotiana benthamiana using a Bamboo mosaic virus-based vector system. By fusion with secretory signal tags, SSExt, derived from the extension protein, and the (SP)10 motif, the yield of the recombinant Gn (rGn) was remarkably increased to approximately 7 mg/kg infiltrated leaves. Ultimately, an rGn-based ELISA was successfully established for the detection of SFTSV-specific antibodies in serum samples from naturally infected monkeys. As validated with the reference method, the specificity and sensitivity of rGn-ELISA were 94% and 96%, respectively. In conclusion, utilizing well-suited fusion tags facilitates rGn production and purification in substantial quantities while preserving its antigenic properties. The rGn-ELISA, characterized by its commendable sensitivity and specificity could serve as a viable alternative diagnostic method for assessing SFTSV seroprevalence. KEY POINTS: • SFTSV Gn, fused with secretory signal tags, was expressed by the BaMV-based vector. • The plant fusion tags increased expression levels and eased the purification of rGn. • The rGn-ELISA was established and validated; its specificity and sensitivity > 94%.

Identification and epidemiological study of an uncultured flavivirus from ticks using viral metagenomics and pseudoinfectious viral particles.

During their blood-feeding process, ticks are known to transmit various viruses to vertebrates, including humans. Recent viral metagenomic analyses using next-generation sequencing (NGS) have revealed that blood-feeding arthropods like ticks harbor a large diversity of viruses. However, many of these viruses have not been isolated or cultured, and their basic characteristics remain unknown. This study aimed to present the identification of a difficult-to-culture virus in ticks using NGS and to understand its epidemic dynamics using molecular biology techniques. During routine tick-borne virus surveillance in Japan, an unknown flaviviral sequence was detected via virome analysis of host-questing ticks. Similar viral sequences have been detected in the sera of sika deer and wild boars in Japan, and this virus was tentatively named the Saruyama virus (SAYAV). Because SAYAV did not propagate in any cultured cells tested, single-round infectious virus particles (SRIP) were generated based on its structural protein gene sequence utilizing a yellow fever virus-based replicon system to understand its nationwide endemic status. Seroepidemiological studies using SRIP as antigens have demonstrated the presence of neutralizing antibodies against SAYAV in sika deer and wild boar captured at several locations in Japan, suggesting that SAYAV is endemic throughout Japan. Phylogenetic analyses have revealed that SAYAV forms a sister clade with the Orthoflavivirus genus, which includes important mosquito- and tick-borne pathogenic viruses. This shows that SAYAV evolved into a lineage independent of the known orthoflaviviruses. This study demonstrates a unique approach for understanding the epidemiology of uncultured viruses by combining viral metagenomics and pseudoinfectious viral particles.

pH-dependent virucidal effects of weak acids against pathogenic viruses.

BACKGROUND: Weak acids, such as acetic acid, show virucidal effects against viruses, and disinfectants are considered effective virucidal agents possibly because of their low pH, depending on the proton concentration. This study aimed to evaluate the efficacy of different weak acids (acetic, oxalic, and citric acids) and eligible vinegars under different pH conditions by comparing their inactivation efficacies against enveloped and non-enveloped viruses. METHODS: Acetic, oxalic, and citric acids were adjusted to pH values of 2, 4 and 6, respectively. They were also diluted from 1 M to 0.001 M with distilled water. Enveloped influenza A virus (FulV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and non-enveloped feline calicivirus (FCV) were treated with adjusted weak acids for up to 30 min. These viruses were also reacted with white distilled vinegar (WDV) and grain-flavored distilled vinegar (GV) for up to 30 min. Infectious viral titers after the reactions were expressed as plaque-forming units per mL. RESULTS: Acetic acid showed virucidal effects against FulV at pH 4, whereas citric and oxalic acids did not. Acetic and citric acids inactivated SARS-CoV-2 at pH 2, whereas oxalic acid did not. All acids showed virucidal effects against FVC at pH 2; however, not at pH 4. The virucidal effects of the serially diluted weak acids were also reflected in the pH-dependent results. WDV and GV significantly reduced FulV titers after 1 min. SARS-CoV-2 was also susceptible to the virucidal effects of WDV and GV; however, the incubation period was extended to 30 min. In contrast, WDV and GV did not significantly inactivate FCV. CONCLUSIONS: The inactivation efficacy of weak acids is different even under the same pH conditions, suggesting that the virucidal effect of weak acids is not simply determined by pH, but that additional factors may also influence these effects. Moreover, eligible vinegars, the main component of which is acetic acid, may be potential sanitizers for some enveloped viruses, such as FulV, in the domestic environment.

Delphinidins from Maqui Berry (Aristotelia chilensis) ameliorate the subcellular organelle damage induced by blue light exposure in murine photoreceptor-derived cells.

BACKGROUND: Blue light exposure is known to induce reactive oxygen species (ROS) production and increased endoplasmic reticulum stress, leading to apoptosis of photoreceptors. Maqui berry (Aristotelia chilensis) is a fruit enriched in anthocyanins, known for beneficial biological activities such as antioxidation. In this study, we investigated the effects of Maqui berry extract (MBE) and its constituents on the subcellular damage induced by blue light irradiation in mouse retina-derived 661W cells. METHODS: We evaluated the effects of MBE and its main delphinidins, delphinidin 3-O-sambubioside-5-O-glucoside (D3S5G) and delphinidin 3,5-O-diglucoside (D3G5G), on blue light-induced damage on retinal cell line 661W cells. We investigated cell death, the production of ROS, and changes in organelle morphology using fluorescence microscopy. The signaling pathway linked to stress response was evaluated by immunoblotting in the whole cell lysates or nuclear fractions. We also examined the effects of MBE and delphinidins against rotenone-induced mitochondrial dysfunction. RESULTS: Blue light-induced cell death, increased intracellular ROS generation and mitochondrial fragmentation, decreased ATP-production coupled respiration, caused lysosomal membrane permeabilization, and increased ATF4 protein level. Treatment with MBE and its main constituents, delphinidin 3-O-sambubioside-5-O-glucoside and delphinidin 3,5-O-diglucoside, prevented these defects. Furthermore, MBE and delphinidins also protected 661W cells from rotenone-induced cell death. CONCLUSIONS: Maqui berry may be a useful protective agent for photoreceptors against the oxidative damage induced by exposure to blue light.

Antiviral effects of micafungin against pteropine orthoreovirus, an emerging zoonotic virus carried by bats.

Bat-borne emerging zoonotic viruses cause major outbreaks, such as the Ebola virus, Nipah virus, and/or beta coronavirus. Pteropine orthoreovirus (PRV), whose spillover event occurred from fruits bats to humans, causes respiratory syndrome in humans widely in South East Asia. Repurposing approved drugs against PRV is an effective tool to confront future PRV pandemics. We screened 2,943 compounds in an FDA-approved drug library and identified eight hit compounds that reduce viral cytopathic effects on cultured Vero cells. Real-time quantitative PCR analysis revealed that six of eight hit compounds significantly inhibited PRV replication. Among them, micafungin used clinically as an antifungal drug, displayed a prominent antiviral effect on PRV. Secondly, the antiviral effects of micafungin on PRV infected human cell lines (HEK293T and A549), and their transcriptome changes by PRV infection were investigated, compared to four different bat-derived cell lines (FBKT1 (Ryukyu flying fox), DEMKT1 (Leschenault's rousette), BKT1 (Greater horseshoe bat), YUBFKT1 (Eastern bent-wing bats)). In two human cell lines, unlike bat cells that induce an IFN-γ response pathway, an endoplasmic reticulum stress response pathway was commonly activated. Additionally, micafungin inhibits viral release rather than suppressing PRV genome replication in human cells, although it was disturbed in Vero cells. The target of micafungin's action may vary depending on the animal species, but it must be useful for human purposes as a first choice of medical care.

Description of three new bat-associated species of hard ticks (Acari, Ixodidae) from Japan.

In Eurasia, the geographically most widespread ixodid tick species of the bat families Rhinolophidae Gray, Vespertilionidae Gray, and Miniopteridae Dobson were considered to belong to four species, Ixodesvespertilionis Koch, I.collaris Hornok, I.ariadnae Hornok, and I.simplex Neumann. Previous data attest that bat-associated tick species from Eastern Asia show remarkable genetic difference from the above four tick species, but in the absence of detailed morphological comparison these were regarded as conspecific. In this study we compensate for this lack of data on three bat-associated tick species, reporting their morphological comparison, as well as molecular and phylogenetic relationships. According to the results we describe the females of three tick species new to science, i.e., I.nipponrhinolophi Hornok & Takano, sp. nov., I.fuliginosus Hornok & Takano, sp. nov., and I.fujitai Hornok & Takano, sp. nov. In case of all three new tick species the cytochrome c oxidase subunit (coxI) gene showed remarkably high sequence differences from the species that they previously were thought to belong to, well exceeding the average limit delineating ixodid tick species. This, as well as observed morphological differences fully justify their taxonomical status as new species.

Microanatomical organization of hepatic venous lymphatic system in humans.

Lymphatic fluid drains from the liver via the periportal lymphatic, hepatic venous lymphatic, and superficial lymphatic systems. We performed a postmortem study to clarify the three-dimensional structure and flow dynamics of the human hepatic venous lymphatic system, as it still remains unclear. Livers were excised whole from three human cadavers, injected with India ink, and sliced into 1-cm sections from which veins were harvested. The distribution of lymphatic vessels was observed in 5 µm sections immunostained for lymphatic and vascular markers (podoplanin and CD31, respectively) using light microscopy. Continuity and density of lymphatic vessel distribution were assessed in en-face whole-mount preparations of veins using stereomicroscopy. The structure of the external hepatic vein wall was assessed with scanning electron microscopy (SEM). The lymphatic dynamics study suggested that lymphatic fluid flows through an extravascular pathway around the central and sublobular veins. A lymphatic vessel network originates in the wall of sublobular veins, with a diameter greater than 110 µm, and the peripheral portions of hepatic veins and continues to the inferior vena cava. The density distribution of lymphatic vessels is smallest in the peripheral portion of the hepatic vein (0.03%) and increases to the proximal portion (0.22%, p = 0.012) and the main trunk (1.01%, p < 0.001), correlating positively with increasing hepatic vein diameter (Rs = 0.67, p < 0.001). We revealed the three-dimensional structure of the human hepatic venous lymphatic system. The results could improve the understanding of lymphatic physiology and liver pathology.

Disseminated histiocytic sarcoma in a squirrel monkey (Saimiri sciureus).

A 14-years-old squirrel monkey was euthanized due to weakness. Histopathological examination revealed multifocal growth of oval cells with severe atypia in the liver, spleen, and bone marrow. The neoplastic cells were positive for histiocytic markers (Iba1, HLA-DR, CD204). This is the fourth case of histiocytic sarcoma in non-human primates.

Lethal Disease in Dogs Naturally Infected with Severe Fever with Thrombocytopenia Syndrome Virus.

Severe fever with the thrombocytopenia syndrome virus (SFTSV) causes fatal disease in humans, cats, and cheetahs. In this study, the information on seven dogs with SFTS was summarized. All dogs showed anorexia, high fever, leukopenia, and thrombocytopenia, two dogs showed vomiting and loose stool, and five dogs had tick parasites. All dogs also had a history of outdoor activity. The SFTSV gene was detected in all dogs. Remarkably, three dogs (43%) died. SFTSV was isolated from six dogs and the complete genomes were determined. A significant increase in anti-SFTSV-IgG antibodies was observed in two dogs after recovery, and anti-SFTSV-IgM antibodies were detected in four dogs in the acute phase. Using an ELISA cut-off value of 0.410 to discriminate between SFTSV-negative and positive dogs, the detection of anti-SFTSV-IgM antibodies was useful for the diagnosis of dogs with acute-phase SFTS. Four out of the ninety-eight SFTSV-negative dogs possessed high anti-SFTSV IgG antibody titers, indicating that some dogs can recover from SFTSV infection. In conclusion, SFTSV is lethal in some dogs, but many dogs recover from SFTSV infection.

Anti-melanogenic effects of glucosylceramides and elasticamide derived from rice oil by-products in melanoma cells, melanocytes, and human skin.

Glucosylceramides (GlcCer), which are present in many edible plants, suppress melanin production in mouse melanocytes. Rice GlcCer consist of multiple molecules that comprise different types of sphingoid bases as well as diverse lengths and stereotypes of free fatty acids. Adjacent to the GlcCer fraction, there are free ceramides (Cer) as minor constituents. However, the anti-melanogenic activities of individual GlcCer and Cer remain unknown. Therefore, we herein isolated 13 GlcCer and elasticamide, a Cer [AP] from the gummy by-products of rice bran oil, and examined their anti-melanogenic activities. In theophylline-induced melanogenesis in B16 melanoma cells, GlcCer [d18:2(4E,8Z)/18:0], GlcCer [d18:2(4E,8Z)/20:0], and elasticamide significantly suppressed melanin production with IC50 values of 6.6, 5.2, and 3.9 µM, respectively. Elasticamide, but not GlcCer [d18:2 (4E,8Z)/20:0], suppressed melanogenesis in human 3D-cultured melanocytes and the expression of tyrosinase-related protein 1 in normal human melanocytes. Based on these results, we conducted a clinical trial on the effects of rice ceramide extract (Oryza ceramide®), containing 1.2 mg/day of GlcCer and 56 µg/day of elasticamide, on UV-B-induced skin pigmentation. The ingestion of Oryza ceramide® for 8 weeks significantly suppressed the accumulation of melanin 7 days after UV irradiation (1288 and 1546 mJ/cm2 ·S). Rice-derived GlcCer and elasticamide, which exhibited anti-melanogenic activities, were suggested to contribute to the suppressive effects of Oryza ceramide® on UV-induced skin pigmentation. Although the mechanisms underlying the anti-melanogenic activities of GlcCer remain unclear, elasticamide was identified as a promising Cer that exhibits anti-melanogenic activity. PRACTICAL APPLICATIONS: The anti-melanogenic activities of rice-derived GlcCer and elasticamide currently remain unclear. We herein demonstrated the inhibitory effects of individual GlcCer and elasticamide on melanogenesis in melanoma cells, melanocytes, and human skin.

A comprehensive list of the Bunyavirales replication promoters reveals a unique promoter structure in Nairoviridae differing from other virus families.

Members of the order Bunyavirales infect a wide variety of host species, including plants, animals and humans, and pose a threat to public health. Major families in this order have tri-segmented negative-sense RNA genomes, the 5' and 3' ends of which form complementary strands that serve as a replication promoter. Elucidation of the mechanisms by which viral polymerases recognize the promoter to initiate RNA synthesis is important for understanding viral replication and pathogenesis, and developing antivirals. A list of replication promoter configuration patterns may provide details on the differences in the replication mechanisms among bunyaviruses. By using public sequence data of all known bunyavirus species, we constructed a comprehensive list of the replication promoters comprising 40 nucleotides in both the 5' and 3' ends of the genome that form a specific complementary strand. Among tri-segmented bunyaviruses, members of the family Nairoviridae, including the highly pathogenic Crimean-Congo hemorrhagic fever virus, have evolved a GC-rich promoter structure differing from that of other families. The unique promoter structure might be related to the large genome size of the family Nairoviridae among bunyaviruses, and the large genome architecture might confer pathogenic advantages. The promoter list provided in this report is useful for predicting the virus family-specific replication mechanisms of bunyaviruses.

Risk assessment of infection with severe fever with thrombocytopenia syndrome virus based on a 10-year serosurveillance in Yamaguchi Prefecture.

In Japan, the first patient with severe fever with thrombocytopenia syndrome was reported in Yamaguchi in 2012. To understand the severe fever with thrombocytopenia syndrome virus (SFTSV) infection in this region, a retrospective surveillance in sika deer and wild boars in Yamaguchi was conducted using a virus-neutralizing (VN) test. The result revealed that 510 of the 789 sika deer and 199 of the 517 wild boars were positive for anti-SFTSV antibodies. Interestingly, seroprevalence in sika deer increased significantly from 2010-2013 to 2015-2020. The SFTSV gene was detected in one of the 229 serum samples collected from sika deer, but not from wild boars. In conclusion, SFTSV had spread among wild animals before 2012 and expanded gradually around 2013-2015 in Yamaguchi.

Isolation and molecular characterization of Polychromophilus spp. (Haemosporida: Plasmodiidae) from the Asian long-fingered bat (Miniopterus fuliginosus) and Japanese large-footed bat (Myotis macrodactylus) in Japan.

Bats (order, Chiroptera) account for more than one-fifth of all mammalian species in the world and are infected by various intra-erythrocytic parasites of the family Plasmodiidae (Apicomplexa: Haemosporida), including Polychromophilus Dionisi, 1899. Recent advance in the molecular characterization of haemosporidian isolates has enabled their accurate identification, particularly in the last decade. Studies are actively conducted in tropical regions, Europe, and Australia; however, data on haemosporidian infection in bats in Asian temperate areas, including Japan, remain limited. In this study, 75 bats of 4 species (Miniopterus fuliginosus, Myotis macrodactylus, Rhinolophus nippon, and Rhinolophus cornutus) were captured at three sites in western Japan (Yamaguchi Prefecture), and haemosporidian parasites were screened microscopically and molecularly via nested polymerase chain reaction (PCR) targeting the cytochrome b (cytb), cytochrome c oxidase subunit I (cox-1), apicoplast caseinolytic protease C (clpc), and nuclear elongation factor 2 (EF2) genes. The survey detected Polychromophilus melanipherus in 15 (40.5%) miniopterid bats (M. fuliginosus) and Polychromophilus murinus in 6 (46.2%) vespertilionid bats (M. macrodactylus), whereas none of the 25 rhinolophid bats (R. nippon and R. cornutus) was infected, indicating the robust host specificity for miniopterid (P. melanipherus) and vespertilionid (P. murinus) bats regardless of orthotopic nesting. The 15 Polychromophilus cytb sequences obtained from 11 miniopterid and 4 vespertilionid bats were classified into six cytb haplotypes (three for each species), showing no region-specific variation in a phylogenetic tree of Polychromophilus isolates in the Old World. Similarly, multiple haplotypes (seven for cox-1 and nine for clpc) and genotypes (three for EF2) were characterized for the Japanese isolates of Polychromophilus, and the results were consistent with those based on a haemosporidian cytb analysis. Bat flies (Nycteribia allotopa and another undetermined Nycteribia sp.) collected from the body surface of bats harbored Polychromophilus oocysts on the external surface of the midgut. This is the first study to report the isolation and molecular characterization of Polychromophilus spp. in miniopterid and vespertilionid bats in the temperate area of Asia (western Japan). Future studies should evaluate the global prevalence of haemosporidian infections in bats.

Roles of raccoons in the transmission cycle of severe fever with thrombocytopenia syndrome virus.

The present study investigated severe fever with thrombocytopenia syndrome virus (SFTSV) infection in raccoons in Wakayama Prefecture from 2007 to 2019. To perform surveillance, an enzyme-linked immunosorbent assay (ELISA) was established, and the sensitivity and specificity of the ELISA were 100% in comparison with a 50% focus-reduction neutralization assay. Using the established ELISA, we performed serosurveillance of SFTSV infection in 2,299 raccoons in Tanabe region, Wakayama Prefecture from 2007 to 2019. The first anti-SFTSV-positive raccoon was captured in October 2009. The seroprevalence of SFTSV infection was <10% between April 2009 and March 2013, 23.9% between April 2013 and March 2014, 37.5% between April, 2014 and March 2015, and over 50% from April 2015. Next, we performed detection of SFTSV genes in sera of raccoons captured in Wakayama Prefecture after April 2013. The results indicated that 2.4% of raccoons were positive for SFTSV genes and that the frequency of SFTSV infection among raccoons between January and March (0.7%) was lower than that between April and June (3.4%). In addition, virus genes were detected from many specimens, including sera and feces of two raccoons, and viral antigens were detected in lymphoid cells in lymphoid follicles in the colon by immunohistochemical staining. In conclusion, SFTSV had recently invaded the area and had rapidly spread among wild animals. The first patient in this area was reported in June 2014, indicating that raccoons are good sentinels for assessing the risk of SFTSV in humans.

Nationwide survey of hepatitis E virus infection among wildlife in Japan.

In Japan, hepatitis E virus (HEV) causes hepatitis in humans through the consumption of raw or undercooked meat, including game meat. In the present study, nationwide surveillance of HEV infection among a total of 5,557 wild animals, including 15 species, was conducted in Japan. The prevalence of anti-HEV antibodies in wild boar was 12.4%, with higher positive rates in big boars (over 50 kg, 18.4%) than in small individuals (less than 30 kg, 5.3%). Furthermore, HEV RNA was more frequently detected in piglets than in older boars. Interestingly, the detection of HEV among wildlife by ELISA and RT-PCR suggested that HEV infection in Sika deer was a very rare event, and that there was no HEV infection among wild animals except for wild boar, Sika deer and Japanese monkeys. In conclusion, wild boar, especially piglets, are at high risk of HEV infection, while other wild animals showed less risk or no risk of HEV transmission.

Comprehensive Surveillance of Virus Infection among Captive African Pygmy Hedgehogs in Japan.

African pygmy hedgehogs (Atelerix albiventris) are popular exotic pets in Japan, and their breeding numbers have recently increased. Although various diseases have been reported in hedgehogs, including skin, respiratory, neurological, and neoplastic diseases, most of the causes remain unidentified. In this study, we investigated herpesvirus, adenovirus, and coronavirus infections among 150 African pygmy hedgehogs in Japan and evaluated the correlations between virus infection and diseases. A novel herpesvirus named Atelerix albiventris herpesvirus 1 (AAHeV), and African pygmy hedgehog adenovirus 1 (AhAdV-1) were detected in 14 and 3 oral swab samples, respectively. AAHeV infection may be related to neurological clinical signs. Interestingly, no hedgehog with a neoplastic disorder tested positive for AAHeV. Further research is required to determine the pathogenicity and prevalence of the detected viruses.