Lethal severe fever with thrombocytopenia syndrome virus infection causes systemic germinal centre failure and massive T cell apoptosis in cats

Introduction

Severe fever with thrombocytopenia syndrome (SFTS) is a fatal viral disease characterized by high fever, thrombocytopenia, leukopenia, and multi-organ haemorrhage. Disruption of the humoral immune response and decreased lymphocyte numbers are thought to contribute to the disease severity. These findings have been obtained through the analysis of peripheral blood leukocytes in human patients, whereas analysis of lymph nodes has been limited. Thus, in this study, we characterized the germinal centre response and apoptosis in the lymph nodes of cats with fatal SFTS, because SFTS in cats well mimics the pathology of human SFTS.

Methods

Lymph node tissue sections collected during necropsy from seven fatal SFTS patients and five non-SFTS cases were used for histopathological analysis. Additionally, lymph node tissue sections collected from cats with experimental infection of SFTS virus (SFTSV) were also analysed.

Results

In the lymphoid follicles of cats with SFTS, a drastic decrease in Bcl6- and Ki67-positive germinal centre B cells was observed. Together, the number of T cells in the follicles was also decreased in SFTS cases. In the paracortex, a marked increase in cleaved-caspase3 positivity was observed in T cells. These changes were independent of the number of local SFTS virus-positive cell. Furthermore, the analysis of cats with experimental SFTSV infection revealed that the intrafollicular Bcl6- and CD3-positive cell numbers in cats with low anti-SFTSV antibody production were significantly lower than those in cats with high anti-SFTSV antibody production.

Discussion

These results suggest that dysfunction of the humoral response in severe SFTS was caused by the loss of germinal centre formation and massive apoptosis of T cells in the lymph nodes due to systemically circulating viruses.

Meningoencephalomyelitis Caused by Brucella Canis: A Case Report and Literature Review

Human brucellosis, one of the most common zoonoses worldwide, is rare in Japan. Brucella canis is the specific pathogen of human brucellosis carried by dogs. According to an epidemiological study of B. canis infection in Japan, B. canis is the specific pathogen of human brucellosis in dogs. We herein report a rare case of meningoencephalomyelitis caused by B. canis in a 68-year-old Japanese man. Neurobrucellosis was diagnosed based on a serum tube agglutination test and abnormal cerebrospinal fluid findings. The patient was started on targeted treatment with a combination of doxycycline and streptomycin. Although extremely rare, neurobrucellosis should be considered in patients with a fever of unknown origin and unexplained neurological symptoms.

A Case of Uncomplicated Bacteremia Caused by Capnocytophaga canimorsus in an Immunocompetent Patient

This report describes uncomplicated bacteremia caused by Capnocytophaga canimorsus in an immunocompetent woman who presented with rigor and fever. She was hemodynamically stable. Two blood samples were immediately cultured because rigor indicated bacteremia. Although her symptoms were relieved, Gram-negative rods grew from blood cultures. She noted that she had been bitten by her dog before the first examination. The bacterium was confirmed as C. canimorsus by gene analysis. Infection with C. canimorsus can be fatal when accompanied by sepsis in elderly or immunocompromised patients. However, this case was considered rare as the patient was 41 years old and immunocompetent.

Non-severe Serovar Type E Capnocytophaga canimorsus Infection in a Post-splenectomy Male: A Case Report

Capnocytophaga canimorsus (CP) causes severe infections in immunocompromised individuals. Three serovars (A, B, and C) are known to be responsible for more than 90% of infections associated with dog bites, although these three constitute only 8% of the serovars carried by dogs. We experienced a post-splenectomy non-severe case of CP withserovar type E, which has never been isolated in Japan. The prognosis of type E CP infections may be better than that of types A, B, and C infections because of the disproportion of serovars between clinical human isolates and dog oral isolates.

Capnocytophaga catalasegens sp. nov., isolated from feline oral cavities

Three bacterial strains, KC07075, KC07079 and KC07084^T, were isolated from the oral cavity of cats in 2007 in Japan. These strains were Gram-negative rods, exhibited gliding motility, grew in air with 5 % CO₂, and showed oxidase activity, but not catalase activity. The 16S rRNA gene sequences of the three strains were 100 % identical. The 16S rRNA gene sequence of strain KC07084^T showed 92.1 and 91.9% identity to the type strains of Capnocytophaga canis and Capnocytophaga felis, respectively, and showed 89.3-91.6% identity to other Capnocytophaga species. The major cellular fatty acids of strain KC07084^T were iso-C_15 : 0 (58.4 %) and summed feature 11 (13.1 %). The G+C content of DNA from strain KC07084^T was 33.7 mol%, and the genome size was 2.92 Mbp. Strains KC07075, KC07079 and KC07084^T showed digital DNA-DNA hybridization values (dDDH) values of 99.9 % and average nucleotide identity (ANI) values of 99.98 % with each other, strain KC07084^T had dDDH values of 18.7-28.2 % and ANI values of 67.12-72.30 % to the type strains of other Capnocytophaga species. All known species of the genus Capnocytophaga inhabiting the oral cavity of dogs and cats have catalase activity, but the three strains, including type strain KC07084^T, lacked catalase activity. These results of the phylogenetic analysis of the 16S rRNA gene sequence, biochemical characteristics, and dDDH and ANI values suggest that strain KC07084^T represents a novel species. We propose the name Capnocytophaga catalasegens sp. nov., with KC07084^T as the type strain (=JCM 32682^T=DSM 107252^T).

Putative Novel Species of Genus Capnocytophaga, Capnocytophaga stomatis Bacteremia in a Patient with Multiple Myeloma after Direct Contact with a Cat

Capnocytophaga species are among the typical zoonotic pathogens causing infections following direct contact with animals. Recently, a putative novel species of zoonotic Capnocytophaga, Capnocytophaga stomatis, was reported. We herein report the first case of bacteremia caused by C. stomatis. A woman in her 80s with multiple myeloma who was receiving bortezomib and dexamethasone therapy was admitted to our hospital with a 2-day history of a fever and right calf redness. She was often licked by her cat. On a blood culture, thin, Gram-negative rods were detected, which were identified as C. stomatis by whole-genome sequencing. The patient was successfully treated with ampicillin-sulbactam treatment. Our case highlights the pathogenic potential of the putative novel Capnocytophaga, C. stomatis, in immunocompromised hosts.

Diagnostic system for the detection of severe fever with thrombocytopenia syndrome virus RNA from suspected infected animals

Background

Severe fever with thrombocytopenia syndrome virus (SFTSV) causes severe hemorrhagic fever in humans and cats. Clinical symptoms of SFTS-infected cats resemble those of SFTS patients, whereas SFTS-contracted cats have high levels of viral RNA loads in the serum and body fluids. Due to the risk of direct infection from SFTS-infected cats to human, it is important to diagnose SFTS-suspected animals. In this study, a reverse transcription polymerase chain reaction (RT-PCR) was newly developed to diagnose SFTS-suspected animals without non-specific reactions.

Methodology/principle findings

Four primer sets were newly designed from consensus sequences constructed from 108 strains of SFTSV. A RT-PCR with these four primer sets successfully and specifically detected four clades of SFTSV. Their limits of detection are 1–10 copies/reaction. Using this RT-PCR, 5 cat cases among 56 SFTS-suspected animal cases were diagnosed as SFTS. From these cats, IgM or IgG against SFTSV were detected by enzyme-linked immunosorbent assay (ELISA), but not neutralizing antibodies by plaque reduction neutralization titer (PRNT) test. This phenomenon is similar to those of fatal SFTS patients.

Conclusion/significance

This newly developed RT-PCR could detect SFTSV RNA of several clades and from SFTS-suspected animals. In addition to ELISA and PRNT test, the useful laboratory diagnosis systems of SFTS-suspected animals has been made in this study.

Capnocytophaga felis sp. nov. isolated from the feline oral cavity

Four strains, KC07070^T, KC07105, 11 025B-8C and 11 026B-8-C, were isolated from the oral cavity of cats in 2007 or 2011 in Japan. These strains were Gram-stain-negative rods, exhibited gliding motility, grew in air with 5 % CO₂ and showed catalase and oxidase activity. The sequences of 16S rRNA genes of the four strains were 100 % identical. Additionally, the sequences of 16S rRNA genes of KC07070^T had identity to those of the type strains of Capnocytophaga canimorsus (97.7 %), Capnocytophaga cynodegmi (97.8 %) and Capnocytophaga canis (97.4 %) and 91.2-93.8% identity to those of other species of the genus Capnocytophaga. The major cellular fatty acids of KC07070^T were iso-C_15 : 0 (56.2 %) and summed feature 11 (14.9 %). The G+C content of the DNA from KC07070^T was 35.6 mol%, and the genome size was 2.88 Mbp. KC07070^T had digital DNA-DNA hybridization (dDDH) values of 26.2-27.6% and average nucleotide identity (ANI) values of 75.4-83.3 % to the type strains of the closest relatives, C. canimorsus, C. cynodegmi and C. canis. These results of phylogenetic analysis of 16S rRNA gene sequence, cellular fatty acids compositions and dDDH and ANI values indicate that strain KC07070^T represents a novel species, for which we propose the name Capnocytophaga felis sp. nov., with type strain KC07070^T (=JCM 32681^T=DSM 107251^T).

An Immunocompetent Case of Capnocytophaga canimorsus Infection Complicated by Secondary Thrombotic Microangiopathy and Disseminated Intravascular Coagulation

A 62-year-old woman with no previous history developed a Capnocytophaga canimorsus infection followed by thrombotic microangiopathy (TMA) and disseminated intravascular coagulation (DIC). She was treated with antibiotics and plasma exchange (PE) and recovered. C. canimorsus sepsis sometimes causes not only DIC but also TMA. The mortality of TMA is extremely high, so we should not hesitate to perform PE when a patient shows TMA symptoms.

Imported Brucellosis In The Era Of Dramatically Increasing Immigrants And Foreign Travelers From Endemic Areas: Occupational Hazards Of Secondary Infection Among Laboratory Technicians In A Nonendemic Country

Background

Brucellosis, an important zoonotic disease, is endemic in various parts of the world. Patients diagnosed with brucellosis in developed countries are often travelers and immigrants from endemic areas. This pathogen is listed as biosafety level 3, which means that it is highly contagious and therefore a risk to clinical laboratory technicians.

Case presentation

A 43-year-old Chinese man, who could not understand Japanese, visited our hospital because of an intermittent fever that had persisted for 5 months. Associated symptoms included muscle pain whenever he had a fever. He reported currently working as a welder in Japan. However, his previous employment working in animal husbandry in Heilongjiang, mainland China was not determined at the initial visit owing to language barriers. Two sets of blood culture showed nonfermenting gram-negative bacilli, initially misidentified as Ochrobactrum anthropi and subsequently identified as Brucella abortus. Six-week doxycycline and rifampicin were administered, with intravenous gentamicin for the initial 1 week. The patient recovered without relapse, confirmed by the negative result of a Brucella agglutination test. The patient’s wife and three laboratory technicians were required to undergo blood examinations, which revealed no evidence of infection; however, they received prophylaxis with 3 weeks’ doxycycline and rifampicin.

Conclusion

In nonendemic countries, immigrants with imported brucellosis can be treated, to prevent secondary brucellosis infection, an occupational hazard among laboratory technicians. Greater attention is needed for positive findings of blood cultures, which may initially be misidentified as O. anthropi. When providing medical care for immigrants with fever of unknown origin, it is especially important for primary care physicians to overcome language barriers so as to assess pertinent information regarding their home country, such as previous employment, to prevent the spread the imported zoonoses in the era of a dramatically increasing number of immigrants and foreign travelers.

Epidemiological Survey of Babesia divergens Asia Lineage in Wild Sika Deer (Cervus nippon) by Using Direct PCR in Japan

Babesia divergens is the major causal agent of zoonotic human babesiosis across Europe. Previously, we reported the detection of a B. divergens Asia lineage in wild sika deer (Cervus nippon) in Japan which was genetically closely related to the European B. divergens. To further elucidate its etiology, we conducted a large epidemiological survey by combining lineage-specific PCR system and blood direct PCR. The infection rate of the Asia lineage was 6.6% (116/1,747) throughout Japan, where Hokkaido (45%), Nagano (17%), Iwate (12%), Gunma (11%), and Yamanashi (11%) were highly enzootic (> 10%) among the 30 prefectures examined. European B. divergens was not detected. A geographical information system (GIS) map revealed dense populations of PCR-positive deer in the mountains including the Japanese Alps in eastern Honshu, and Hokkaido. These areas markedly overlapped with the major habitats of Ixodes persulcatus, a principal tick vector responsible for the transmission of the Asia lineage. Other areas in southern Japan including Miyazaki, Kagoshima, and Shimane Prefectures, where positive sika deer were sporadically detected, may be habitats for other tick species involved in the enzootic cycle as I. persulcatus were scarce. The rise in human babesiosis cases is occasionally attributed to healthy blood donors who were unaware of tick bites and Babesia infection. Therefore, there is an urgent need to investigate whether infections in humans have occurred in Japan.

Chronic Brucellosis in Japan

Human brucellosis, one of the most common zoonoses worldwide, rarely occurs in Japan, and only a few chronic cases have been reported. We herein report the case of a 39-year-old Japanese woman with chronic human brucellosis, considered a Brucella canis infection, that persisted for 19 years. Her medical history and fever pattern suggested chronic brucellosis, and the diagnosis was made based on the results of a serum tube agglutination test (SAT). After undergoing combination therapy with streptomycin and doxycycline, she achieved symptomatic relief and showed negative SAT results. Even in non-endemic areas, chronic brucellosis is an important differential diagnosis in patients with long-term persistent fatigue or a fever.

Characterization of three strains of Capnocytophaga canis isolated from patients with sepsis

Capnocytophaga canimorsus and Capnocytophaga cynodegmi, both commensal bacteria in the oral cavities of dogs and cats, are zoonotic pathogens. In particular, C. canimorsus causes sepsis and fatal septic shock. Recently, a novel Capnocytophaga species, C. canis, was isolated from the oral cavities of healthy dogs. It is reportedly oxidase-negative and therefore considered avirulent in humans. In the present study, three strains of C. canis were isolated from Japanese patients with sepsis. All three strains, HP20001, HP33001 and HP40001, were oxidase-positive. Nucleotide sequence identities of the 16S rRNA gene of the three strains to the C. canimorsus type strain ATCC35979, C. cynodegmi type strain ATCC49044 and C. canis type strain LMG29146 were 96.9-97.0%, 96.9-97.0% and 99.7-99.8%, respectively. Multi-locus sequence analysis based on seven house-keeping genes, dnaJ, fumC, glyA, gyrB, murG, trpB and tuf, revealed that the oxidase-positive C. canis strains isolated in Japan and oxidase-negative strains of C. canis from canine oral cavities in Switzerland were clustered in different genetic subgroups. These results indicate that the virulence of C. canis strains in humans is associated with oxidase activity.

Sepsis Caused by Newly Identified Capnocytophaga canis Following Cat Bites: C. canis Is the Third Candidate along with C. canimorsus and C. cynodegmi Causing Zoonotic Infection

Sepsis caused by a Capnocytophaga canis infection has only been rarely reported. A 67-year-old female with a past medical history of splenectomy was admitted to our hospital with fever and general malaise. She had been bitten by a cat. She showed disseminated intravascular coagulation and multi-organ failure because of severe sepsis. On blood culture, characteristic gram-negative fusiform rods were detected; therefore, a Capnocytophaga species infection was suspected. A nucleotide sequence analysis revealed the species to be C. canis, which was newly identified in 2016. C. canis may have low virulence in humans; however, C. canis with oxidase activity may cause severe zoonotic infection.

A relapsing fever group Borrelia sp. is widely distributed among wild deer in Japan

A relapsing fever group Borrelia sp. was detected from the blood of wild deer (Cervus nippon) in Japan. The Borrelia sp. was distributed nationwide among deer with an overall prevalence of 26% in blood samples. The prevalence of infection was significantly higher in fawns (48.4%) compared to adult deer (23.6%). Sequencing analysis reveals that this Borrelia sp. belongs to the hard tick-borne relapsing fever borreliae, and that it forms a single lineage based on sequences of the flagellin and glycerophosphodiester phosphodiesterase genes. Borrelial genome copy number was estimated at 8.8 × 10³ genome copies/μl of blood. Other hard tick-borne relapsing fever borrelia (e.g. Borrelia miyamotoi) were not detected in deer blood in this study. These findings suggest that wild deer may act as reservoirs for this Borrelia sp. in Japan.

Rat-bite fever due to Streptobacillus notomytis isolated from a human specimen

Rat-bite fever (RBF) is a disease that usually presents with fever, arthralgia and skin rash. Streptobacillus moniliformis was considered the main cause of RBF among the genus Streptobacillus. Although with similar clinical presentation, RBF due to Streptobacillus notomytis is unusual in humans. To the best of our knowledge, we present a case involving the first isolate of S. notomytis in humans. A 63-year-old woman was admitted to our hospital with fever, rash and polyarthritis. She recalled being bitten by a rat on her finger 5 days before presentation. Clinical manifestations were compatible with rat-bite fever (RBF) and the diagnosis was confirmed by the detection of Streptobacillus species from both blood and pustule samples. Initial polymerase chain reaction tests revealed that the organism was S. moniliformis. However, thorough genetic analysis revealed the organism to be S. notomytis. The condition was successfully treated with ampicillin.

Capnocytophaga canimorsus sepsis in a methotrexate-treated patient with rheumatoid arthritis

Capnocytophaga canimorsus is a gram-negative rod that can be transmitted primarily by dog bites. This life-threatening organism commonly causes sepsis in patients with splenectomy or alcoholism. A 53-year-old rheumatoid arthritis male treated with methotrexate (MTX) for 5 years was admitted for a 4-day history of fever and dyspnea. He had been bitten on a finger by the family dog 4 days before onset. Laboratory tests revealed pancytopenia, acute renal failure, and evidence of disseminated intravascular coagulation, and he subsequently developed acute respiratory distress syndrome. Furthermore, blood cultures grew gram-negative bacilli and despite intensive treatment, he died 5 days after admission. Later, C. canimorsus was identified from his culture samples using a species-specific polymerase chain reaction. C. canimorsus infections should be considered in the differential diagnosis of sepsis for immunocompromised hosts following animal bites.

Isolation of Brucella inopinata-Like Bacteria from White's and Denny's Tree Frogs

Brucella inopinata strain BO1 and B. sp. strain BO2 isolated from human patients, respectively, are genetically different from classical Brucella species. We isolated bacteria of the genus Brucella from two species of wild-caught tropical frogs kept in the facilities in Japan: White's tree frog, which inhabits Oceania, and Denny's tree frog, which inhabits Southeast Asia. Phylogenetic analyses based on 16S rRNA and recA gene sequences and multilocus sequence analysis showed that two isolates of Brucella spp. showed significant similarity to BO1, BO2, and the isolates from other wild-caught frogs. These results suggest that a variety of frog species are susceptible to a novel clade of Brucella bacteria, including B. inopinata.

Epidemiological and pathological study of feline morbillivirus infection in domestic cats in Japan

BACKGROUND

Feline morbillivirus (FmoPV) is a novel paramyxovirus found to infect domestic cats. FmoPV has been isolated in several countries in Asia and Europe and is considered to have genetic diversity. Also, it is suspected to be associated with feline renal diseases including tubulointerstitial nephritis (TIN), which affects domestic cats with a high incidence rate.

RESULTS

To clarify the state of FmoPV infection among domestic cats in Japan, an epidemiological survey was conducted. Twenty-one out of 100 cats were found to have serum antibodies (Ab) against FmoPV-N protein by indirect immunofluorescence assay (IF) using FmoPV-N protein-expressing HeLa cells. Twenty-two of the cats were positive for FmoPV RNA in the urine and/or renal tissues. In total, 29 cats were positive for Ab and/or viral RNA. These FmoPV-infected cats were classified into three different phases of infection: RNA+/Ab + (14 cats), RNA+/Ab- (8 cats) and RNA-/Ab + (7 cats). In immunohistochemistry (IHC), 19 out of 29 cats were positive for FmoPV-N protein in kidney tissues; however, the FmoPV-N protein was located in the inflammatory lesions with severe grade in only four out of the 19 cats. Since 15 out of 29 infected cats were positive for viral RNA and Ab, approximately half of the infected cats were persistently infected with FmoPV.

CONCLUSIONS

A statistically significant difference was observed between infection of FmoPV and the presence of inflammatory changes in renal lesions, indicating a relationship between FmoPV infection and feline renal diseases. However, we could not obtain histopathological evidence of a relationship between FmoPV infection and TIN.

Streptobacillus notomytis sp. nov., isolated from a spinifex hopping mouse (Notomys alexis Thomas, 1922), and emended description of Streptobacillus Levaditi et al. 1925, Eisenberg et al. 2015 emend

A pleomorphic, Gram-negative, rod-shaped, indole-, oxidase- and catalase-negative, non-spore-forming, non-motile bacterium was isolated in 1979 from the heart of a spinifex hopping mouse (Notomys alexis Thomas, 1922) with septicaemia and stored as Streptobacillus moniliformis in the strain collection of the Animal Health Laboratory, South Perth, Western Australia (AHL 370-1), as well as under CCUG 12425. On the basis of 16SrRNA gene sequence analyses, the strain was assigned to the genus Streptobacillus, with 99.4 % sequence similarity to the type strain of Streptobacillus moniliformis, 95.6 %sequence similarity to the type strain of Streptobacillus hongkongensis and 99.0 %sequence similarity to the type strain of Streptobacillus felis. The clear differentiation of strain AHL 370-1T from Streptobacillus moniliformis, Streptobacillus hongkongensis and Streptobacillus felis was also supported by rpoB, groEL and recA nucleotide and amino acid sequence analysis. Average nucleotide identity was 87.16 % between strain AHL 370-1T and Streptobacillus moniliformis DSM 12112T. Physiological data confirmed the allocation of strain AHL 370-1T to the family Leptotrichiaceae, considering the very similar profiles of enzyme activities and fatty acids compared to closely related species. Within the genus Streptobacillus,isolate AHL 370-1T could also be separated unambiguously from the type strains of Streptobacillus moniliformis, Streptobacillus hongkongensis and Streptobacillus felis by MALDI-TOF mass spectrometry. Two further strains (KWG2 and KWG24) isolated from asymptomatic black rats in Japan were highly similar to AHL 370-1T. On the basis of these data, we propose the novel species Streptobacillus notomytis sp. nov., with the type strain AHL370-1T (=CCUG 12425T=DSM 100026T=CCM 8593T=EF 12425T).

Streptobacillus ratti sp. nov., isolated from a black rat (Rattus rattus)

An indole-, oxidase- and catalase-negative, non-motile bacterium, strain OGS16T, was isolated from an oral swab of a feral black rat (Rattus rattus) in 2007 in Japan. It stained Gram-negative and had pleomorphic, rod-shaped, non-spore-forming cells. Based on 16S rRNA gene sequence analyses, strain OGS16T was assigned to the genus Streptobacillus, with 16S rRNA gene sequence similarities of 99.3, 99.0, 98.6 and 95.5% to the type strains of Streptobacillus moniliformis, Streptobacillus notomytis, Streptobacillus felis and Streptobacillus hongkongensis, respectively. Strain OGS16T could also be differentiated clearly from other species of the genus Streptobacillus by rpoB, groEL and recA nucleotide and deduced amino acid sequence analysis. DNA-DNA relatedness as obtained by average nucleotide identity was 89.10% between strain OGS16T and Streptobacillus moniliformis DSM 12112T. Chemotaxonomic and physiological data for strain OGS16T were congruent with results for other closely related members of the family Leptotrichiaceae, represented by highly similar enzyme profiles and fatty acid patterns. MALDI-TOF MS analysis also proved suitable in discriminating strain OGS16T unequivocally from all currently described taxa of the genus Streptobacillus. On the basis of these data, we propose the novel species Streptobacillus ratti sp. nov., with the type strain OGS16T (=JCM 31098T=DSM 101843T). The G+C content of the DNA of the type strain is 25.9 mol% and the genome size is 1.50 Mbp.

Yip1A, a novel host factor for the activation of the IRE1 pathway of the unfolded protein response during Brucella infection

Brucella species replicate within host cells in the form of endoplasmic reticulum (ER)-derived vacuoles. The mechanisms by which the bacteria are sequestered into such vacuoles and obtain a continuous membrane supply for their replication remain to be elucidated. In the present study, we provided several lines of evidence that demonstrate the mechanism by which B. abortus acquires the ER-derived membrane. First, during Brucella infection, the IRE1 pathway, but not the PERK and ATF6 pathways, of the unfolded protein response (UPR) was activated in a time-dependent manner, and the COPII vesicle components Sar1, Sec23, and Sec24D were upregulated. Second, a marked accretion of ER-derived vacuoles was observed around replicating bacteria using fluorescent microscopy and electron microscopy. Third, we identified a novel host factor, Yip1A, for the activation of the IRE1 pathway in response to both tunicamycin treatment and infection with B. abortus. We found that Yip1A is responsible for the phosphorylation of IRE1 through high-order assembly of Ire1 molecules at ER exit sites (ERES) under the UPR conditions. In Yip1A-knockdown cells, B. abortus failed to generate the ER-derived vacuoles, and remained in endosomal/lysosomal compartments. These results indicate that the activation of the IRE1 pathway and the subsequent formation of ER-derived vacuoles are critical for B. abortus to establish a safe replication niche, and that Yip1A is indispensable for these processes. Furthermore, we showed that the autophagy-related proteins Atg9 and WIPI1, but not DFCP1, were required for the biogenesis of the ER-derived membrane compartments. 　On the basis of our findings, we propose a model for intracellular Brucella replication that exploits the host UPR and ER-derived vacuole formation machineries, both of which depend on Yip1A-mediated IRE1 activation.

The genus Brucella is a serious intracellular pathogen that causes brucellosis in a wide range of animals including humans. Infection with Brucella spp. results in a significant economic and health burden due to its high infectivity, chronic nature, and difficulties in vaccine production. Better understanding of the host-pathogen interplay that supports Brucella replication is essential for the development of effective treatments for brucellosis. The unfolded protein response (UPR) has been implicated in the pathogenesis of several viral and bacterial infections. These pathogens modulate individual pathways of the UPR to enable their replication in host cells. Autophagy has also been linked to the survival of several intracellular pathogens. They subvert autophagic machineries of host cells to establish their safe replication niche. In the present study, we show that the activation of the IRE1 pathway of the UPR and the subsequent formation of ER-derived vacuoles are crucial for intracellular survival of B. abortus. In addition, we identified a novel host factor Yip1A that is responsible for these processes. Characterization of the function of Yip1A will provide new insights into the molecular mechanisms by which Brucella spp. replicates in host cells.

Identification of a natural recombination in the F and H genes of feline morbillivirus

Feline morbillivirus (FmoPV) has recently been identified in Hong Kong and Japan. FmoPV is considered to belong to the genus Morbillivirus, in the family Paramyxoviridae. In this study, the complete nucleotide sequences of three strains of FmoPV detected in cats in Japan were determined. Among the six genes in FmoPV; N, P/V/C, M, F, H and L, the P gene showed the highest polymorphism in the nucleotide and putative amino acid sequences among the FmoPV strains. There was no geographical association in terms of the FmoPV phylogeny; however, from extensive phylogenetic and recombination analyses, we found that one Japanese FmoPV strain, MiJP003, was a probable recombinant between two virus strains in the independent lineages found in Japan and Hong Kong, respectively. The recombination was considered to have occurred within the F and H genes. Such recombination is thought to be involved in the evolution of FmoPV.

Cutting Edge: Brucella abortus exploits a cellular prion protein on intestinal M cells as an invasive receptor

Brucella abortus is a Gram-negative bacterium causing brucellosis. Although B. abortus is known to infect via the oral route, the entry site in the gastrointestinal tract has been unclear. We found that B. abortus was selectively internalized by microfold cells (M cells), a subset of epithelial cells specialized for mucosal Ag uptake. During this process, colocalization of cellular prion protein (PrP(C)) and B. abortus was evident on the apical surface as well as in subapical vacuolar structures in M cells. Internalization of B. abortus by M cells of PrP(C)-deficient (Prnp(-/-)) mice was greatly reduced compared with that in wild-type mice. Furthermore, an oral infection study revealed that translocation of B. abortus into the Peyer's patch was significantly lower in Prnp(-/-) than in wild-type mice. These observations suggest that orally infected B. abortus invades the host through M cells by using PrP(C) on the apical surface of M cells as an uptake receptor.

Prevalence of Capnocytophaga canimorsus and Capnocytophaga cynodegmi in dogs and cats determined by using a newly established species-specific PCR

Capnocytophagacanimorsus and Capnocytophagacynodegmi, fastidious gram-negative rods, are commensal microbes thriving in the oral cavities of dogs and cats. C. canimorsus can sometimes cause fatal systemic infections in humans. In the present study, we established a specific PCR which could identify and distinguish C. canimorsus from C. cynodegmi. The prevalence of Capnocytophaga spp. in dogs and cats was determined using this method. C. canimorsus was detected in 74% of dogs and 57% of cats. C. cynodegmi was detected in 86% of dogs and 84% of cats. The prevalence of Capnocytophaga spp. obtained in this study is somewhat higher than those reported previously where bacterial isolation method was used for identification. This is probably due to the fact that the PCR detection is more sensitive compared to bacterial isolation. Our findings suggest the importance of informing people who belong to high-risk groups as well as health care workers on C. canimorsus infection and its potential risk to people particularly to those who are immunocompromised.

Evaluation of a microplate agglutination test (MAT) for serological diagnosis of canine brucellosis

A microplate agglutination test (MAT) was compared with the tube agglutinin test (TAT), a standard test for the diagnosis of Brucella canis, in terms of the sensitivity and specificity. The results showed that MAT was more sensitive, simpler to perform and easier to read the results than TAT. On top of that the MAT allows us to handle a larger number of samples at once. Using this method we conducted sero-surveillance of the prevalence of B. canis in dogs kept in an Animal Shelter located in Kanagawa Prefecture. Twelve of 485 (2.5%) showed seropositive against B. canis. These results indicate that B. canis infection in dogs is still occurring in Japan.

Detection of Streptobacillus spp. in feral rats by specific polymerase chain reaction

Streptobacillus moniliformis is an etiological agent of rat-bite fever and Haverhill fever in human infection. As the currently available methods for identifying the causative bacteria are not satisfactory, we attempted to establish them by PCR using newly designed primers for the 16S rRNA gene of S. moniliformis. We then determined the prevalence of Streptobacillus spp. in two species of feral rats that inhabit an urban region in Japan, because information on the prevalence of the bacteria in feral rats is obscure. The use of PCR with newly designed primers showed that an extremely high proportion of R. norvegicus harbored the bacteria (61/66, 92%), whereas the prevalence was only 58% in R. rattus (30/52). The nucleotide sequence analysis of the 16S rRNA gene of Streptobacillus spp. isolated from oral swabs of feral rats showed at least two different types of bacteria among isolates from R. norvegicus and R. rattus.

Simultaneous detection of the genus Brucella by combinatorial PCR

We have developed a combinatorial polymerase chain reaction (PCR) procedure to identify four major species of the genus Brucella simultaneously. Four pairs of primers targeting the genes encoding a cell surface protein (BCSP31) and outer membrane proteins (omp2b, omp2a and omp31) were prepared. PCR using these primers gave rise to specific patterns of amplification for each Brucella spp. examined in this study. B. abortus could be identified when fragments of BCSP31 and omp2b/2a were amplified by B. abortus-specific primers. B. melitensis could be identified by the amplification of fragments of BCSP31, omp2b/2a and omp31 using pair of primers B4/B5, JRF/JPR-ab and omp31. Identification of B. canis could be achieved when the amplicons of omp2b/2a were detected by B. canis-specific primers, as could the identification of BCSP31 and omp31. If specific amplifications occurred using all pairs of primers, the strain was identified as B. suis. Combinatorial PCR reported here thus appeared to be an ideal method of identifying Brucella spp., the causative pathogen of human brucellosis.

Examination of quantitative and fractal analysis of sway characteristics of the center of foot pressure movement during a static upright posture. Analysis based on alcohol intake

AIM

This study aimed to examine the sway characteristics of center of foot pressure (CFP) movement during a static upright posture under the influence of alcohol by using quantitative and fractal analysis.

METHODS

Eleven healthy young people participated. They drank in a range of 0.54-1.83 ml/kg of alcohol, standardized by body mass, within 10 min. Blood pressure, heart rate, 2 types of nervous function tests and the CFP movement were measured before and after the alcohol intake. Thirty-six parameters of the CFP movement were used for quantitative analysis. Diffusion coefficient, scaling exponent and critical point coordinates were used in fractal analysis.

RESULTS

Quantitative analysis confirmed that the CFP parameters such as distance, velocity and area were significantly changed, although the parameters evaluating cyclical characteristics and center average were not. Fractal analysis confirmed that critical point coordinates existed at time-lag=1.0 before and after the alcohol intake, and the short-term region (ST) and long-term region (LT) could be separated. A diffusion coefficient in the ST was larger than that in the LT, and the scaling exponent was over 0.5 in the ST and under 0.5 in the LT.

CONCLUSIONS

Influences of alcohol intake were found in amount of body-sway, but not in the displacement or periodicity of the CFP parameters. Fractal analysis confirmed that CFP movement was dependent on time-series, and its characteristics changed before and after the time-series critical point and was unsteady.

Targeted disruption of MAIL, a nuclear IkappaB protein, leads to severe atopic dermatitis-like disease

MAIL (molecule-possessing ankyrin repeats induced by lipopolysaccharide) is a nuclear IkappaB protein that is also termed interleukin-1-inducible nuclear ankyrin repeat protein or inhibitor of nuclear factor kappaB (IkappaB) zeta. In this study, we generated Mail-/- mice to investigate the roles of MAIL in whole organisms. Mail-/- mice grew normally until 4-8 weeks after birth, when they began to develop lesions in the skin of the periocular region, face, and neck. MAIL mRNA and protein were constitutively expressed in the skin of wild type controls, especially in the keratinocytes. Serum IgE was higher in Mail-/- mice than in normal. Histopathological analysis indicated that the Mail-/- skin lesions appeared to be atopic dermatitis (AD) eczema with inflammatory cell infiltration. In addition, markedly elevated expression of some chemokines such as thymus and activation-regulated chemokine was detected in the Mail-/- skin lesions, similar to that observed in the skin of patients with AD. In Mail-/- mice, MAIL-deficient keratinocytes might be activated to produce chemokines and induce intraepidermal filtration of inflammatory cells, resulting in the onset of the AD-like disease. These findings suggest that MAIL is an essential molecule for homeostatic regulation of skin immunity. The Mail-/- mouse is a valuable new animal model for research on AD.

Dorsal skin responses to subchronic ultraviolet B (UVB)-irradiation in Wistar-derived hypotrichotic WBN/ILA-Ht rats

Dorsal skin responses to a subchronic UVB-irradiation (10kJ/m2/rat /day), were examined in Wistar-derived hypotrichotic WBN/ILA-Ht rats for up to 3 months. Hyperplasia of epidermal cells and hair follicle epithelial cells as well as parakeratosis developed at 1 month and progressed thereafter, resulting in a prominent epidermis thickening and formation of epidermal ingrowths projecting into the dermis. At the same time, the percentage of proliferating cell nuclear antigen (PCNA)-positive epidermal cells significantly increased after I month. In some portions of the hyperplastic epidermis, especially of the epidermal ingrowths, keratinocytes were somewhat pleomorphic and migrated into the dermis. In the upper dermis, edema with capillary congestion, mast cell infiltration and fibroblast proliferation developed at I month, and the intensity of edema and the number of dermal mast cells was most prominent at 3 months. Edema spread to the epidermis, resulting in intercellular edema and subsequent dissociation of epidermal cells. Degeneration of collagen fibers was also detected in the upper dermis, especially beneath the epidermis. In addition, although not significant because of a large individual difference, the serum IgE concentration, showed a tendency to increase after 2 months. The present study clarified the characteristics of the dorsal skin responses to a subchronic UVB-irradiation in rats.

Enterotoxin adjuvants have direct effects on T cells and antigen-presenting cells that result in either interleukin-4-dependent or -independent immune responses

In an in vitro study, Escherichia coli heat-labile toxin (LT) was shown to directly affect activated CD4(+) T cells and support interleukin (IL)-5 production in IL-4-deficient (IL-4(-/-)) mice, whereas cholera toxin (CT) did not. Both LT and CT enhanced B7-2 expression on B cells and macrophages. These effects were not influenced by CD40-CD40 ligand cosignaling. Addition of LT- or CT-treated antigen-presenting cells to anti-CD3-triggered CD4(+) T cells resulted in the induction of T cell proliferative responses. Further, these responses were inhibited by anti-B7-2 monoclonal antibody. Cocultivation of CD4(+) T cells with LT- or CT-treated antigen-presenting cells and anti-CD3 enhanced Th1- and IL-4-mediated Th2-type cytokine production. The results from in vitro studies were supported by in vivo studies in IL-4(-/-) mice, in which LT induced mucosal IgA responses but CT did not. Thus, although both LT and CT induce mucosal adjuvant responses via IL-4-dependent Th2-type responses, LT also elicits Th1- and IL-4-independent Th2-type responses.

Leukoencephalopathy with cerebral amyloid angiopathy: a semiquantitative and morphometric study

To investigate changes in caliber of vessels in leukoencephalopathy with cerebral amyloid angiopathy (CAA) we performed a histological and morphometric study of cerebral arteries in this disease. We histologically examined changes in cortico-leptomeningeal arteries in five cases of leukoencephalopathy with CAA and compared their morphometrically determined wall-to-lumen ratio [(external diameter-internal diameter) x 0.5/internal diameter] with those of amyloid-negative arteries to estimate stenotic changes. Additionally, we compared wall-to-lumen ratios of medullary arteries in brains with CAA and white matter lesions (WML) (CAA(+)/WML(+), n = 5), subcortical arteriosclerotic encephalopathy without CAA (CAA(-)/WML(+), n = 7), and neither CAA nor white matter lesions (CAA(-)/WML(-), n = 5). Amyloid-positive arteries had thinned walls and dilated lumens. The external diameter and the wall-to-lumen ratio for amyloid-positive arteries was smaller than for amyloid-negative arteries in CAA(+)/WML(+) brains. There was no significant difference in the external diameters among the three groups. The wall-to-lumen ratio for medullary arteries in CAA(-)/WML(+) brains was significantly greater than for CAA(+)/WML(+) and CAA(-)/WML(-), but there was no significant difference between CAA(+)/WML(+) and CAA(-)/WML(-). Amyloid deposition causes degeneration of the tunica media, resulting in thinning of the wall and dilation of the lumen. The tunica media of small arteries is important in regulation of cerebral blood flow with degeneration causing impairment of cerebrovascular autoregulation in response to blood pressure. This impairment may lead to white matter lesions.

Mucosal Th1- versus Th2-type responses for antibody- or cell-mediated immunity to simian immunodeficiency virus in rhesus macaques

Simian immunodeficiency virus (SIV)-specific B cell responses and the Th1- or Th2-type profiles of cytokine expression were determined for rhesus macaques immunized with SIV antigens via the iliac lymph nodes (by use of a targeted lymph node [TLN] procedure) or orally with SIV p55gag plus cholera toxin (CT) as a mucosal adjuvant. Analysis of CD4+ T cells purified from SIV-stimulated peripheral blood mononuclear cells of immunized macaques revealed that Th2 cytokine production gradually increased after the second and third TLN immunization. Analysis of SIV-specific B cell responses revealed that peak SIV-specific IgA B cell responses followed the third TLN immunization and occurred during peak Th2-type T cell responses. Oral immunization of macaques with p55gag plus CT induced interferon-gamma-secreting Th1-type and select Th2-type cytokine-producing CD4+ T helper cells, which most likely accounted for the induction of p55-specific systemic IgG and mucosal IgA responses.

Nasal immunization of nonhuman primates with simian immunodeficiency virus p55gag and cholera toxin adjuvant induces Th1/Th2 help for virus-specific immune responses in reproductive tissues

Female rhesus macaques were nasally immunized with p55gag (p55) of SIV and cholera toxin as a mucosal adjuvant. Nasal immunization induced Ag-specific IgA and IgG Abs in mucosal secretions (e.g., cervicovaginal secretions, rectal washes, and saliva) and serum. Furthermore, high numbers of p55-specific IgA and IgG Ab-forming cells were induced in mucosal effector sites, i.e., uterine cervix, intestinal lamina propria, and nasal passage. p55-specific CD4+ T cells in both systemic and mucosal compartments expressed IFN-gamma and IL-2 (Th1-type)- as well as IL-5, IL-6, and IL-10 (Th2-type)-specific mRNA. Moreover, p55-specific CTL activity was demonstrated in lymphocytes from blood, tonsils, and other lymphoid tissues. These results show that nasal immunization with SIV p55 with cholera toxin elicits both Th1- and selective Th2-type cytokine responses associated with the induction of SIV-specific mucosal and serum Abs, and CTL activity. These results offer a promise for the development of protective mucosal immunity to SIV.

[A case of hereditary motor and sensory neuropathy with pyramidal tract sign, optic nerve atrophy and mental retardation]

The patient was a 61-year-old man who suffered from gait disturbance since childhood. He also had mental retardation. Gait disturbance was slowly progressive. His mother, sister, brother and son of his sister suffered from gait disturbance. On neurological examination, he showed mental retardation, optic nerve atrophy and neural deafness. He also showed severe muscle atrophy and weakness of bilateral lower limbs associated with pes cavus. Muscle tonus of lower limbs and patellar tendon reflex were increased bilaterally. Achilles tendon reflex was absent. Babinski and Chaddock signs were positive. Superficial and deep sensations were almost normal. There were no cerebellar signs. Blood chemistry was normal. On nerve conduction studies, motor nerve conduction velocity of the upper limbs was normal and that of the posterior tibial nerve was decreased; right 36.0m/sec, left 29.7m/sec. Sensory nerve conduction velocity of the median nerve was slightly decreased; right 36.5m/sec, left 45.2m/sec and sural nerve did not respond to electric stimuli. On sural nerve biopsy, the density of myelinated fibers was severely decreased. Onion bulb formation was not observed. We classified this case as hereditary motor and sensory neuropathy (HMSN) type II based on nerve conduction studies and findings from sural nerve biopsy. HMSN with pyramidal tract sign has been classified as type V and HMSN with optic nerve atrophy as type VI. This case had characteristic symptoms as type V and VI. Histopathological findings of HMSN type V and VI have not been established yet. This case might provide an important clue for classification of HMSN.

Nasal Immunization of Nonhuman Primates with Simian Immunodeficiency Virus p55gag and Cholera Toxin Adjuvant Induces Th1/Th2 Help for Virus-Specific Immune Responses in Reproductive Tissues

Female rhesus macaques were nasally immunized with p55gag (p55) of SIV and cholera toxin as a mucosal adjuvant. Nasal immunization induced Ag-specific IgA and IgG Abs in mucosal secretions (e.g., cervicovaginal secretions, rectal washes, and saliva) and serum. Furthermore, high numbers of p55-specific IgA and IgG Ab-forming cells were induced in mucosal effector sites, i.e., uterine cervix, intestinal lamina propria, and nasal passage. p55-specific CD4+ T cells in both systemic and mucosal compartments expressed IFN-γ and IL-2 (Th1-type)- as well as IL-5, IL-6, and IL-10 (Th2-type)-specific mRNA. Moreover, p55-specific CTL activity was demonstrated in lymphocytes from blood, tonsils, and other lymphoid tissues. These results show that nasal immunization with SIV p55 with cholera toxin elicits both Th1- and selective Th2-type cytokine responses associated with the induction of SIV-specific mucosal and serum Abs, and CTL activity. These results offer a promise for the development of protective mucosal immunity to SIV.

Presence of anti-ovalbumin IgE antibody in the sera of laboratory-reared squirrel monkeys (Saimiri sciureus) fed quail eggs

In this study, we examined serum anti-ovalbumin (OVA) IgE and IgG antibodies in laboratory-reared squirrel monkeys (Saimiri sciureus), that were fed a boiled quail egg everyday. We found that 36 of 95 monkeys (38%) possessed specific IgE and 44% (42/95) had specific IgG against OVA. These antibody titers seemed to increase with age. There was, however, no apparent correlation between the anti-OVA IgE and IgG antibody titers.

Induction of Th2 cytokine expression for p27-specific IgA B cell responses after targeted lymph node immunization with simian immunodeficiency virus antigens in rhesus macaques

To determine if there is an association between the isotype of simian immunodeficiency virus (SIV)-specific B cell responses and the profile of Th1 and Th2 cytokine expression, rhesus macaques were immunized with SIV antigens via the iliac lymph nodes, using a targeted lymph node (TLN) immunization procedure. When CD4+ T cells purified from antigen-stimulated peripheral blood mononuclear cells were analyzed, the levels of Th2 cytokine production were gradually increased after the second and third immunizations. However, interferon-gamma production did not change. Analysis of SIV-specific B cell responses revealed that the main isotype was IgG after the second and third immunizations. In addition, a peak of SIV-specific IgA B cell responses was noted following the third immunization. These findings suggest that the induction of Th2 type responses in TLN-immunized rhesus macaques reflects the sequence of initial induction of SIV-specific IgG-producing cells followed by IgA-secreting cells.

No mutations in cystatin C gene in cerebral amyloid angiopathy with cystatin C deposition

To investigate the relationship between cerebral amyloid angiopathy (CAA) and cystatin C, we studied five CAA patients on whose cerebral blood vessels colocalization of cystatin C and beta-protein was recognized immunohistochemically. One patient was suspected as familial CAA and the other patients were sporadic cases. Two patients had low concentration of cystatin C in their cerebrospinal fluid (CSF) as we have previously reported in CAA patients. Enzyme-linked immunosorbent assay (ELISA) revealed that cystatin C and beta-protein have been included at the ratio of about 1:100 in the crude amyloid fibrils of one patient. Using a monoclonal antibody (MAb) against cystatin C, we performed affinity chromatography and immunoblotting on her amyloid fibril fraction. Eluate showed a band with a mol wt of 14,000 and the N-terminal 14 amino acid residues of 14-kDa protein were identical with that of cystatin C. This molecular weight is not identical to that of the truncated form of cystatin C deposited in hereditary cerebral hemorrhage with amyloidosis in Iceland (HCHWA-I), but that of normal cystatin C. DNA sequence analysis of five patients showed no point mutations in the cystatin C gene. Cystatin C and beta-protein colocalization, which was recognized in amyloid lesions of CAA, suggests that cystatin C deposition may be related to beta-protein deposition. We hypothesize that cystatin C deposition in sporadic cerebral amyloid angiopathy with cystatin C deposition (SCCAA) involves a different mechanism from that in HCHWA-I, which may be related to low CSF concentration of cystatin C without amino acid substitutions.