Natural severe fever with thrombocytopenia syndrome virus infection in domestic cats in Japan.

Severe fever with thrombocytopenia syndrome (SFTS) is a recently discovered emerging infectious disease. A zoonotic disease with a high fatality rate in human beings, clinical information on SFTS virus (SFTSV) infection in animals is important. Since 2017, we have diagnosed 24 client-owned cats living in western Japan with SFTS, by genetic and serological testing. In this study, we characterized the clinical features of SFTS in cats and their associated risk factors, by evaluating the clinical parameters retrospectively. A phylogenetic analysis on SFTSV was also conducted. There were no obvious tendencies in age or sex, outdoor cats were commonly at risk of SFTSV infection. All infected cats showed acute onset of clinical signs including anorexia and lethargy, while 68.2% of the cats showed fever and 41.7% showed vomiting. The case fatality rate was 62.5%. Thrombocytopenia, leukopenia, and elevated serum total bilirubin, serum amyloid A, and creatinine phosphokinase concentration were the characteristic findings in the first clinical blood examination. Phylogenic analysis revealed that regional clustered viruses infect both humans and cats. For pet owners and animal hospitals, SFTS in small animals could be an important public health issue.

Detection of a novel tick-borne flavivirus and its serological surveillance.

Tick-borne encephalitis virus (TBEV), a flavivirus that causes severe neurological symptoms in humans, has been found in Hokkaido, Japan. In the present study, we detected sequences from a novel tick-borne flavivirus, designated Yamaguchi virus (YGV), in liver and serum samples obtained from a wild boar in the Yamaguchi prefecture, Japan. Phylogenetic analysis revealed that YGV belongs to the TBEV complex and is closely related to Langat virus (LGTV). YGV was also detected by specific RT-PCR from 20 in 378 pools of ticks (2923 ticks) collected in Yamaguchi and Wakayama prefectures and from seven in 46 wild boar captured in Wakayama. The major ticks infected with YGV belong to the genus Haemaphysalis. Unfortunately, YGV could not be isolated from any samples from the RT-PCR positive wild boar or ticks. Therefore, ELISA for detection of antibodies against YGV was established using LGTV, and surveillance was performed among wild boar in 10 different prefectures on Honshu Island, the main island of Japan. The results showed that the seroprevalence of tick-borne flavivirus infection in the Wakayama and Hyogo prefectures of western Japan was significantly higher than that in the other prefectures, while antibodies against tick-borne flavivirus were not detected in any wild boar in the Tochigi prefecture in the eastern part of Japan. In addition, wild raccoons or masked palm civets in the Hyogo prefecture did not possess detectable antibodies against tick-borne flaviviruses. In conclusion, YGV appears to be maintained primarily among wild boar and ticks in the western part of Japan. YGV is the second flavivirus (after Japanese encephalitis virus) shown to be circulating on Honshu Island in Japan.

Detection of anti-viral antibodies from meat juice of wild boars.

Wild boars are a reservoir for many zoonotic pathogens and a good sentinel for surveillance of zoonotic viral infections, but collection of serum samples from wild boars in the field is sometimes difficult and requires special equipment and techniques. In this study, ELISA using meat juices extracted from the heart and diaphragm of wild boars, instead of serum samples, was performed to detect antibodies against zoonotic pathogens, Japanese encephalitis virus and hepatitis E virus. The results of ELISA using meat juice samples were significantly correlated with those using serum samples and meat juice contained one-fifth the antibodies of serum samples. As meat juice is easily collected from wild animals in the field without special equipment and techniques, ELISA using meat juice is a simple and superior method for serological survey of zoonosis among wild animals.

The complete genomic sequence of Rhinolophus gammaherpesvirus 1 isolated from a greater horseshoe bat.

In a comprehensive research project on bat viruses, we successfully isolated a novel herpesvirus from the spleen of a greater horseshoe bat (Rhinolophus ferrumequinum) in Japan using a cell line established from the kidney of the same bat. This herpesvirus was a novel gammaherpesvirus (Rhinolophus gammaherpesvirus 1; RGHV-1), which belonged to the genus Percavirus. The whole RGHV-1 genome (147,790 bp) showed that 12 of the 84 genes predicted to contain open reading frames did not show any homology to those of other herpesviruses.

Fatal Tickborne Phlebovirus Infection in Captive Cheetahs, Japan.

Two captive cheetahs from a zoo in Japan died of a severe fever with thrombocytopenia syndrome-like illness. Severe fever with thrombocytopenia syndrome virus, an endemic tickborne phlebovirus, was detected systemically with secretion of infectious viruses into the saliva. These cases highlight the risk for exposure of captive animals to endemic arthropodborne pathogens.

Getah virus epizootic among wild boars in Japan around 2012.

In 2014, an outbreak of Getah virus (GETV) infection occurred in Japan in a horse population that was inoculated with a vaccine against GETV. In this study, we investigated the seroprevalence of GETV infection among wild boars in Japan. Interestingly, the highest rate of anti-GETV-positive wild boars was observed in 2013, which gradually decreased during 2014-2016. The results suggested that GETV spread among wild boars around 2012, resulting in the 2014 outbreak.

[The Clinical Effect of Ramucirumab in the Treatment of Advanced Gastric Cancer in Our Hospital].

Ramucirumab(RAM)was approved for unresectable advanced gastric cancer in March 2015. Recent Japanese gastric cancer treatment guidelines recommended RAM plus paclitaxel(PTX)and RAM alone in the treatment of patients with advanced gastric cancer who had been previously treated with chemotherapy. In this retrospective study, we evaluated the safety and efficacy of RAM alone and PTX plus RAM in these patients. Patients who were administered RAM or PTX plus RAM between March 2015 and December 2016 were enrolled in this study. We compared the clinical outcome of RAM alone(RAM group, n=11)with that of PTX plus RAM(PTX plus RAM group, n=10). The RAM group contained more patients with poor performance status than the PTX plus RAM group. More cases of Grade 3 or 4 adverse events were found in the PTX plus RAM group than in the RAM group. The response rate was 9% in the RAM group and 30% in the PTX plus RAM group. The progression-free survival was 2 months in the RAM group and 3.75 months in the PTX plus RAM group. The overall survival was not reached in the RAM and PTX plus RAM groups. We considered that RAM and PTX plus RAM are safe and effective therapies for advanced gastric cancer patients.

Efficacy of an additional flap operation in bladder-preserving surgery with radical prostatectomy and cystourethral anastomosis for rectal cancer involving the prostate.

PURPOSE: Sphincter-preserving operations performed with bladder-preserving surgery and a cystourethral anastomosis (CUA) do not require a urinary stoma, but leakage from the CUA may develop. The aim of this study was to evaluate the efficacy of performing an additional flap operation. METHODS: The subjects were 39 patients who underwent bladder-preserving surgery for advanced rectal cancer involving the prostate, between 2001 and 2015.32 of whom had a CUA and one of whom had a neobladder. Five of these 32 patients underwent an ileal flap operation, 2 underwent an omental flap operation, and 3 underwent an operation using both flaps. RESULTS: Leakage developed in 3 (30%) of the 10 patients who underwent additional flap operations, but in 14 (60.9%) of the 23 patients who did not undergo a flap operation. The mean periods of catheterization for the patients who suffered leakage were 31 weeks (8-108 weeks) in those without a flap and 16 weeks (8-20 weeks) in those with a flap. Four (33.3%) of the 12 patients with leakage after surgery without a flap had a period of urinary catheterization >30 weeks, and 2 (16.7%) had leakage of CTCAE grade 3. There were no cases of leakage after flap surgery. CONCLUSION: An additional flap operation may decrease the risk of leakage from a CUA.

[Analysis of Oxaliplatin Combination Therapy for Unresectable or Recurrent Gastric Cancer].

We analyzed 26 cases of unresectable or recurrent gastric cancer treated with oxaliplatin(OX)combination therapy between September 2014 and January 2016. The number of unresectable gastric cancer cases was 14 and there were 12 recurrent cases. The number of patients receiving S-1 plus OX(SOX), SOX plus trastuzumab(Tmab), capecitabine(Cape)plus OX(CapeOX), and CapeOX plus Tmab was 17, 1, 6, and 2, respectively. The starting dose of OX was 130mg/m2 in 12 patients and 100mg/m2 in 14. The median follow-up duration from the first treatment was 6 months(1-14). The median number of treatment cycles was 5(1-19). Dose reductions occurred in 14 cases, and treatment delay occurred in 13 cases. Grade 3 adverse events occurred in 2 cases(8%); thrombocytopenia and stomatitis occurred in 1 case. The response rate was 23%, the disease control rate was 69%, and the median relapse-free survival time was 4 months(1-14). OX combination therapy for unresectable or recurrent gastric cancer was feasible in terms of safety and might be effective for disease control.

Emergence of pathogenic coronaviruses in cats by homologous recombination between feline and canine coronaviruses.

Type II feline coronavirus (FCoV) emerged via double recombination between type I FCoV and type II canine coronavirus (CCoV). In this study, two type I FCoVs, three type II FCoVs and ten type II CCoVs were genetically compared. The results showed that three Japanese type II FCoVs, M91-267, KUK-H/L and Tokyo/cat/130627, also emerged by homologous recombination between type I FCoV and type II CCoV and their parent viruses were genetically different from one another. In addition, the 3'-terminal recombination sites of M91-267, KUK-H/L and Tokyo/cat/130627 were different from one another within the genes encoding membrane and spike proteins, and the 5'-terminal recombination sites were also located at different regions of ORF1. These results indicate that at least three Japanese type II FCoVs emerged independently. Sera from a cat experimentally infected with type I FCoV was unable to neutralize type II CCoV infection, indicating that cats persistently infected with type I FCoV may be superinfected with type II CCoV. Our previous study reported that few Japanese cats have antibody against type II FCoV. All of these observations suggest that type II FCoV emerged inside the cat body and is unable to readily spread among cats, indicating that these recombination events for emergence of pathogenic coronaviruses occur frequently.

Seroprevalence of Japanese encephalitis virus infection in captive Japanese macaques (Macaca fuscata).

Japanese encephalitis virus (JEV), which is transmitted by mosquitoes, infects many animal species and causes serious acute encephalitis in humans and horses. In this study, a serosurvey of JEV in Japanese macaques (Macaca fuscata) reared in Aichi Prefecture was conducted using purified JEV as an antigen for ELISA. The results revealed that 146 of 332 monkeys (44 %) were seropositive for JEV. In addition, 35 of 131 monkeys (27 %) born in the facility were seropositive, and the annual infection rate in the facility was estimated as 13 %. Our results provide evidence of the frequent exposure of many Japanese macaques to JEV, suggesting that there is a risk of JEV transmission to humans by mosquitoes.

Dramatic resolution of bullous pemphigoid after surgery for gastric cancer: A case report.

INTRODUCTION: An association between bullous pemphigoid (BP) and internal malignancy has been suggested. However, no reports have documented a dramatic improvement in BP after surgery for gastric cancer. PRESENTATION OF CASE: An 82-year-old Japanese woman was admitted to a local hospital for severe fatigue. On examination, she was diagnosed with BP and gastric cancer. Her BP was resistant to steroid treatment; however, it improved dramatically after surgery for gastric cancer. DISCUSSION: In this case, a strong relationship appeared to exist between BP and gastric cancer. CONCLUSION: This is the first report of a dramatic improvement in BP after surgery for gastric cancer.

High prevalence of hepatitis E virus in wild boar (Sus scrofa) in Yamaguchi Prefecture, Japan.

Hepatitis E virus (HEV) causes a food- and water-borne disease in humans, and Japanese wild boar (Sus scrofa leucomystax) meat is one of the most important sources of infection in Japan. We tested 113 serum samples from wild boar captured in Shimonoseki City, Yamaguchi Prefecture, Japan from 2010 to 2012. Serum samples were tested by enzyme-linked immunosorbent assay (ELISA) using virus-like particles as antigen and nested reverse-transcription PCR (RT-PCR). Anti-HEV IgG antibodies were detected in 47 of the 113 wild boar serum samples (42%), and HEV RNA was detected in five samples (4%). Sequence analysis showed that the five HEV isolates belonged to genotype 4, forming a cluster with a previous isolate from a human hepatitis E case in this region in 2011. These results indicate that wild boar in this region are infected with potentially pathogenic HEV at a high prevalence.

Genetic characterization of coronaviruses from domestic ferrets, Japan.

We detected ferret coronaviruses in 44 (55.7%) of 79 pet ferrets tested in Japan and classified the viruses into 2 genotypes on the basis of genotype-specific PCR. Our results show that 2 ferret coronaviruses that cause feline infectious peritonitis-like disease and epizootic catarrhal enteritis are enzootic among ferrets in Japan.

Characterization of glycoproteins in equine herpesvirus-1.

In this study, we attempted to express twelve glycoproteins of equine herpesvirus-1 (EHV-1) in 293T cells and to characterize these using monoclonal antibodies (MAbs) and horse sera against EHV-1. Expression of glycoprotein B (gB), gC, gD, gG, gI and gp2 was recognized by immunoblot analysis using horse sera, but that of gE, gH, gK, gL, gM and gN was not. Four MAbs recognized gB, four recognized gC and one recognized gp2. Two MAbs against gB cross-reacted with EHV-4. Interestingly, coexpression of gE and gI and gM and gN enhanced their antigenicity. Furthermore, immunoblot analysis of gp2 showed that different molecular masses of gp2 were recognized by the MAb against gp2 and horse sera against EHV-1. In this study, it was demonstrated that at least six glycoproteins were immunogenic to horses, and coexpression of gE and gI and gM and gN was important for enhancement of antigenicity.

Production and characterization of monoclonal antibodies to Japanese encephalitis virus.

In this study, eighteen monoclonal antibodies (MAbs) to recent Japanese encephalitis virus (JEV) genotype I were produced and characterized by plaque reduction neutralization test, western blot analysis, indirect immunofluorescence assay and enzyme-linked immunosorbent assay. All MAbs recognized only envelope (E) protein or conformational epitope of E and precursor membrane proteins. Two MAbs (7E5 and 3-3H8) possessed virus-neutralization activity, and their escape mutants possessed a change of glutamine to histidine at the position of 52 of E protein, suggesting that these neutralizing MAbs recognize the domain I-II hinge region of E protein. Five MAbs recognized all examined flaviviruses, and two were specific to JEV. These MAbs may be useful for differentiation and diagnosis of flaviviruses.

Function of feline signaling lymphocyte activation molecule as a receptor of canine distemper virus.

Morbilliviruses use signaling lymphocyte activation molecule (SLAM) as a receptor for their entry to cells. In this study, a complete gene encoding SLAM of a domestic cat was identified. The identity of feline SLAM with canine one was 73%, and feline SLAM formed the same cluster with those of carnivores. Furthermore, feline cell expressing feline SLAM supported growth of canine distemper virus (CDV) as well as that expressing canine one. These results indicated that feline SLAM can function as a receptor for morbilliviruses, and our established feline cells that express feline SLAM might be useful for analysis of morbilliviruses originated from felids.

Identification of a major immunogenic region of equine herpesvirus-1 glycoprotein E and its application to enzyme-linked immunosorbent assay.

A major immunogenic region of equine herpesvirus (EHV)-1 glycoprotein E (gE) was identified. Firstly, the various fragments of EHV-1 gE were expressed as fusion proteins with glutathione S-transferase (GST) in Escherichia coli and their antigenicities were compared by immunoblot analysis using sera from horses experimentally infected with EHV-1. Thirty-three amino acids of gE (a.a. 169-201) specifically and sensitively reacted with the antibodies induced by EHV-1 but not EHV-4 infection. The corresponding region of EHV-4 gE (a.a. 169-199) did not react with antibodies to EHV-1, indicating that this region is specific for each virus. In addition, when the antigenicities of three 20-mer synthetic peptides of EHV-1 gE, gE1(169-188), gE1(176-195) and gE1(182-201) were compared by enzyme-linked immunosorbent assay (ELISA), gE1(169-188) was found to contain a major B-cell epitope. ELISA using two synthetic peptides, gE1(169-188) and gG4(319-330), previously identified as the major EHV-4-specific epitope in gG, was developed and could specifically detect antibodies to EHV-1 and EHV-4, respectively. In Japan, the EHV-1 deleted in gE gene (EHV-1 ΔgE) virus is expected to be introduced in the field as a new modified live vaccine. This ELISA did not react with antibodies induced by inoculation with EHV-1 ΔgE, indicating that it is a useful method to differentiate between EHV-1 infection and EHV-1 ΔgE inoculation. In conclusion, the ELISA described herein, using synthetic peptides, is a simple method to distinguish between EHV-1 and EHV-4 infections and will be suitable as a vaccine marker after introduction of EHV-1 ΔgE into field horses.

Development and application of an indirect enzyme-linked immunosorbent assay for serological survey of Japanese encephalitis virus infection in dogs.

Japanese encephalitis virus (JEV) causes serious acute encephalitis in humans and horses. Although dogs are good sentinels for assessing the risk of JEV infection to humans, a virus neutralization test has been the only method available for measuring the levels of JEV antibody in dogs. In this study, an indirect enzyme-linked immunosorbent assay (ELISA) using purified viral particles as an antigen, was developed for serological survey of JEV infection in dogs. In dogs inoculated experimentally with JEV, the ELISA detected anti-JEV IgM 3 days after infection, with IgM levels peaking 7 days after infection. Anti-JEV IgG was detected 14 days after infection and peaked on 21-28 days after infection. Virus neutralization titers correlated with anti-JEV immunoglobulins measured by the ELISA. To test the utility of the new assay, the seroprevalence of JEV infection among 102 dogs in Kyushu, Japan, was examined by IgG ELISA and by virus neutralization. The correlation coefficient between the IgG ELISA and virus neutralization was 0.813 (p<0.001); comparison of the IgG ELISA and virus neutralization showed a sensitivity and specificity of 82% and 98%, respectively. The IgG ELISA was used to survey dogs in Bangkok, Thailand and 51% of these dogs were found seropositive for JEV. These data suggest that in the capital city of Thailand, the risk of infection with JEV remains high.