中野 達徳

A case of subclinical hepatitis E virus (HEV) infection was detected by nucleic acid amplification test on blood donation. The patient was followed-up until day 220 after the blood donation but showed no symptoms throughout the observation period. Aspartate aminotransferase and alanine aminotransferase levels reached the maximum values on day 37 with a slight increase but remained in normal ranges from day 67 to 220. The quantity of HEV RNA at the initial examination on day 13 was 1.1 × 102 copies/mL, which increased to 2.8 × 103 copies/mL by day 37. It was not detected from day 67 to 220. Immunoglobulin G class antibody to HEV (anti-HEV IgG) was below the cut-off value until day 37 and exceeded the cut-off value to positive on day 67, accompanied by normalization of liver function and negative conversion of HEV RNA. Thereafter, the titer decreased gradually, falling below the cut-off value on day 163, and continuing negative until day 220. Although the persistent duration of anti-HEV IgG positive is believed to be generally long, it was within only 126 days for this subclinical case. Further investigation is needed to determine whether short-term positivity for anti-HEV IgG is typical in subclinical HEV infection.

岐阜県近郊で発生したE型肝炎13例のE型肝炎ウイルス(HEV)の感染源・感染経路を、問診と原因HEVの遺伝子配列の解析から推測した。全員孤発例であった。2例は生のブタ内臓肉、1例は調理したブタ内臓肉、7例は調理したブタ肉、2例は調理不十分なブタ肉の喫食歴があった。HEVゲノムのORF2領域の412塩基長の配列をもとに近隣結合法で系統樹を作成した。1例はORF1領域を解析した。原因HEVの遺伝子型は、3aが5例、3bが6例、3fが1例、4iが1例であった。13例中2例は原因HEV株に近縁株の登録はなかったが、11例には97%以上の相同性を持つ株が見つかり、地域内拡散8例、国内広域拡散2例、国際拡散1例の3つのパターンに類別された。

In Mie Prefecture, autochthonous hepatitis E cases occurred via homologous hepatitis E virus subgenotype 3e (HEV-3e), namely, Mie indigenous HEV-3e, from 2004 through 2014. We experienced three cases of autochthonous hepatitis E in 2020 in Mie Prefecture, and analyzed the partial HEV genomes recovered from them. The three HEV isolates clustered with Mie indigenous HEV-3e in the phylogenetic tree and exhibited high similarities to it. Mie indigenous HEV-3e had thus reemerged for the first time in six years. One affected patient often consumed meat of wild animals, and another ate undercooked pork liver, although the third case had no clear risk factors. Mie indigenous HEV-3e appears to be maintained in wild animals or domestic pigs.

We experienced a case of autochthonous hepatitis E by hepatitis E virus (HEV) genotype 4. The phyloge-netic tree analysis indicated that the HEV isolate ob-tained from the patient was segregated into the HEV subgenotype 4a (HEV-4a) cluster. The patient had no history of travel abroad, e.g., to China, where HEV-4a strains are endemic. The source and the route of the HEV-4a infection were unknown. Strains of HEV-4a may be indigenous to Japan despite remaining unde-tected to date, either in swine or wild animals. Addi-tional HEV subgenotypes circulating in swine and wild animals in Japan require investigation to reveal the characteristics of HEV-4a infection in autochthonous cases in Japan.

著者らは三重県と岐阜県を中心にE型肝炎の発生状況を調査し、患者の喫食歴などを問診するとともに、原因となったHEVの遺伝子配列を決定し、症例相互の原因HEV株の関係や、データベースから探究した近縁株との関係を調べることで、感染源・感染経路の解明に努めている。今回、問診では互いに接点がないと思われたが、発症時期と遺伝子解析結果から感染源が同一と推測された3組6症例が存在したので、各症例の概要を報告した。6例とも同一経済圏内の発生であり、感染にはブタ肉などの食品の流通や人の往来が関与していると考えられた。

症例は73歳男性で、進行胃癌+肝転移に対する化学療法にて薬剤性間質性肺炎を発症し、プレドニゾロンを12日間投与され軽快傾向で退院した。定期受診にて急性肝障害が指摘され緊急入院となり、グリチルリチン製剤投与にて経過観察中IgAクラスE型肝炎ウイルス陽性が判明し急性E型肝炎と診断した。血小板減少を伴ったが、入院13日目には肝障害が改善したため退院し、血小板数も正常に復した。退院後52日目に再入院して胃癌に対しニボルマブを投与したところ血小板が0.2×10^4/μlまで減少し、血小板輸血とデキサメサゾン投与を行ったが、再入院15日目に上部消化管出血のため死亡した。骨髄穿刺検査の結果と経過から、ニボルマブ投与による免疫性の血小板減少症が考えられた。

We found three pairs of six sporadic acute hepatitis E cases infected with three different genotype 3b hepatitis E virus (HEV) strains, which were 99.7%-100% identical between two cases in each pair within the partial nucleotide sequences of ORF1 and ORF2 regions of the HEV genome. While no common source of infection was recognized within each pair, HEV infections in these cases occurred within the same economic bloc in the central region of Japan. Moreover, nucleotide sequences of the HEV strains from one pair were 99.8% identical to those obtained from pig liver sold in the same economic bloc. These results suggest the importance of continued molecular epidemiologic studies on HEV strains from humans and food products.

A 73-year-old man contracted acute hepatitis E with decreased platelet count in the course of chemotherapy against advanced gastric cancer and administration of corticosteroid for adverse effects of chemotherapy. After the recovery of hepatitis, he underwent the first administration of Nivolumab, and subsequently died of bleeding from the cancer by immune-mediated severe thrombocytopenia. The relationship between the thrombocytopenia after Nivolumab therapy and prior hepatitis E virus (HEV) infection cannot be excluded. The patient ate pig offal before hepatitis E, and the HEV strain obtained from the patient was of genotype 3b, which was prevalent in Japanese pigs. HEV infection should be considered as the cause of liver dysfunction and thrombocytopenia during chemotherapy or treatment by immuno-suppressive agents.

Hepatitis E virus subtype 3f (HEV-3f) strains are usually isolated in Europe and Thailand. Recently, HEV-3f strains were detected from six acute hepatitis E patients in Japan, none of whom had a history of travel to endemic areas. We inferred the origin and transmission route of the six HEV-3f strains. A time-scaled phylogenetic tree of the six strains with reference strains was constructed using a Bayesian statistical inference framework. The time-scaled tree indicated that the six strains independently derived from similar European strains between 2008 and 2014. The pattern suggested recent inflow of multiple HEV-3f strains from Europe to Japan. Japan imports a substantial amount of pork from European countries every year. The emergence of acute hepatitis cases caused by HEV-3f strains in Japan, in patients with no history of travel abroad, might be influenced by the increased opportunities to consume pork products imported from European countries.

Hepatitis E virus (HEV) causes acute or chronic hepatitis in humans worldwide and can be transmitted via the fecal-oral route. Four HEV strains (HE-JA14-2173, HE-JA15-1335, HE-JA15-1920 and HE-JA16-0610) obtained from patients with imported (from Pakistan or India) or autochthonous acute hepatitis E in Japan were most closely related to the Nepalese and Mongolian genotype 1 HEV strains of unassigned subtype within the partial ORF2 sequence. To investigate whether a putative novel subtype (1g) of genotype 1 can be assigned, full-length genomic sequences were determined for the four HEV strains. They shared 95.4-99.2% nucleotide identity over the entire genome, and differed by 6.3-11.7% from the reported HEV strains of subtypes 1a-1f and by only 0.6-4.7% from a Mongolian genotype 1 HEV strain (MNE15-072) of unassigned subtype. A phylogenetic analysis showed that the four HEV strains obtained in the present study formed a cluster with MNE15-072, with a bootstrap value of 100%. Although the p-distance between subtypes 1a and 1f was 0.048-0.083, these five strains showed a higher nucleotide p-distance value of 0.068-0.138 with the genotype 1 HEV strains of subtypes 1a-1f. A BLAST search revealed the presence of candidate members of subtype 1g HEV in at least five other countries, including France, Israel, the Netherlands, Portugal, and the UK, sharing identities of 95.4-99.6% with the HE-JA16-0610 strain within the common sequence of 294-867 nucleotides. These results support the assignment of a new subtype 1g within genotype 1 and suggest a global distribution of subtype 1g strains. Subtype 1g strains found in Europe can be imported from Asia. Further studies are needed to confirm the global distribution of HEV subtype 1g.

バイタル変化や消化器症状、胃瘻部位のトラブルなどにより経腸栄養の中止が必要となることがある。今回、我々は、Stevens-Johnson症候群と考えられる症例において、反復する高熱や頻脈、振戦、および、遷延する低血圧の出現により、経腸栄養の再開時期を躊躇した。これらの症状は、Epstein-Barr virus(EBV)の再燃が関与したと考えられた。EBVのような日和見病原体によって発症する症状により、胃瘻からの経腸栄養の継続が困難となることがあり注意が必要である。(著者抄録)

三重県北部地域在住の67歳の男性が急性肝炎を発症した。IgA-HEV抗体及びHEV RNAが検出され急性E型肝炎と診断された。HEVのsubgenotypeはわが国では稀な3f型と判定された。海外渡航歴はなく国内での感染と考えられた。発症前3ヵ月以内の県外への移動はなかった。狩猟を生業としており、捕獲した猪や鹿の解体も自ら行っていた。保管されていた猪肉から同定されたHEVは3b型に分類されたが、捕獲した動物を素手で解体していたことから、動物からの感染が強く疑われた。3f株による国内感染E型肝炎例は稀で、群馬県、埼玉県及び岐阜県の症例に継いで本例は4例目である。今後広く全国で3f株によるE型肝炎が発生する可能性があり、本来ヨーロッパ株である3f株が土着化しているのか、豚や猪での感染調査を含め、その感染源、感染ルートの解明が急がれる。3f株例では急性肝不全を生じた例も報告されている。E型肝炎では、積極的に遺伝子解析を行い病態との関連性を検討する必要がある。(著者抄録)

50歳男。肝障害にて紹介され、入院時には眼球結膜の黄疸を認めた。画像診断では肝脾腫、胆嚢壁肥厚を認め、IgA-HEV(E型肝炎ウイルス)抗体、HEV RNA陽性よりE型急性肝炎と診断し、グリチルリチン製剤(SNMC)、ウルソデオキシコール酸(UDCA)の投与により検査所見は改善したが、1ヵ月後にT.Bilが異常値を示した。ウイルス感染に惹起された自己免疫性肝障害等の可能性も考慮してSNMC、UDCAとプレドニゾロンを開始するも黄疸は遷延し、T.Bilの正常化には発症から約6ヵ月を要した。本症例は輸血歴、海外渡航歴および野生動物肉摂食歴はなく、感染経路は不明であったが、分子系統解析よりsubtype 3f(HEV-3f)による急性肝炎と診断した。HEV-3fの感染経路と病原性の解明のため、更なる症例の蓄積が必要と考えられた。

三重県北中部地域でE型肝炎ウイルス(HEV)genotype 1a株による2例の急性E型肝炎が発生した。1例目は来日1週間のネパール人で、2例目は三重県在住の日本人であった。二人の患者間に接触はなく、両者から分離されたHEV株の遺伝子解析でも関連性は認められなかった。前者はネパールで感染し、来日後急性E型肝炎を発症した輸入感染症例と考えられたが、後者は発症前約1年間は海外渡航歴がなく、国内感染例と考えられた。1型株の急性E型肝炎国内感染例報告は本邦初と考えられ、国内感染急性E型肝炎の原因として土着株のgenotype 3型株及び4型株だけでなく1型株も考慮しなければならないことが示唆された。国内で発生した急性E型肝炎例についてはgenotypeを解析し、1型株による国内感染例の存在を把握していく事が、防疫上の観点からも重要であると考えられる。(著者抄録)

Background & Aims: Hepatitis E virus (HEV) genotype 4 has mainly been isolated from sporadic hepatitis cases and swine in Asian countries. We analysed the origin and global dispersal history of genotype 4 using a Bayesian phylogeographical approach. Methods: The 412-nucleotide sequences of open reading frame 2 of genotype 4 (47 Japanese, 40 Chinese, 1 Indian, 8 Indonesian, 1 Korean, 1 Taiwanese, 2 Danish and 2 Italian), of which sampling date and location were known, were collected. Evolutionary rate, divergence time, demographic growth and phylogeography were co-estimated in the Bayesian statistical inference framework implemented in the BEAST package to model spatial dispersal on a time-scaled genealogy. Results: The most probable origin of genotype 4 was Japan and the time of origin was 1909 (95% highest posterior density, 1871-1940). Seven lineages of genotype 4 migrated from Japan to China. The analysis also showed the migration of genotype 4 from Japan or China to India and Indonesia and from China to Indonesia, Taiwan, Korea and a few European countries. Conclusions: Swine trade between countries coincided with the migration time and direction of genotype 4 in some cases and was considered the primary cause of dispersal. However, there was no clear cause of dispersal for some cases, for which no records of pig trade were found. Future research should analyse additional nucleotide sequences paired with epidemiological data from various countries to improve our understanding of HEV dispersal.

症例1は63歳男で、食欲不振、嘔気、全身倦怠感にて近医を受診し、肝障害にて紹介入院した。症例2は70歳男で、心窩部痛と嘔気にて近医を受診し、肝炎疑いで紹介入院した。2例ともIgA-HEV抗体陽性、HEV-RNA検査陽性よりE型急性肝炎と診断し、補液と経過観察のみで回復した。問診にて症例1は発症の6〜10週間前に、症例2は発症1ヵ月前にいずれも同一飲食店でブタのレバーと心臓を生で喫食していたことが判明し、感染源として強く疑われた。既報株とともに2症例のHEV株の分子進化系統樹を作成した結果、症例1は遺伝子型4型愛知静岡株に、症例2は3a型のクラスターに属し、系統樹上で全く近縁関係を示さなかった。

An HCV outbreak occurred in 2012 in China, affecting hundreds of patients. We characterized HCV subtype 2a and 6a sequences from 60 and 102 patients, respectively, and co-analyzed them with 82 local controls and 103 calibrating references. The close grouping of the patients' sequences contrasted sharply with the diversity of local controls. Scaled by the calibrating references, the emergence of patients' isolates was estimated at 2-5 years before sampling. In contrast, the controls intermingled with the calibrating references that were much older. For both subtypes, the major and minor clusters could be defined, with the closeness to indicate linked transmission. Conclusion: HCV sequences from the study patients grouped into three subtype 2a and two subtype 6a clusters, in addition to three 6a solitary branches, representing descendants of eight earlier strains that were distinct and otherwise sporadic. Due to iatrogenic transmission through reusing needles, five strains were highly selected and preferentially spread. (C) 2015 Published by Elsevier Inc.

We experienced two cases of acute hepatitis E in Miyazaki Prefecture in the same period. The patients were unknown to each other and did not have any clear causes or common risk factors of hepatitis E virus (HEV) infection. Nucleotide sequences of the HEV isolates revealed that the two isolates were closely related but with different HEV genotype 3 strains. The two cases appeared to be infected from unknown and different sources. Molecular phylogenetic analysis indicated that the strains were probably descendants of the strains which had been isolated from swine herd in Miyazaki Prefecture 12 years previously. This result indicates that the strains persisted in pig farms, in wild life, or in the natural environment in this region. The source should be identified, and efforts should be made to prevent of the spread of the infection. One of the cases had acute facial paralysis, which might be an extra-hepatic manifestation of HEV infection.

宮崎県内で同時期に2例のE型急性肝炎症例を経験した。2例に交友関係、共通の生活歴はなかった。両症例のE型肝炎ウイルス(HEV)株は、遺伝子配列の解析から近縁ではあるが同一株ではなく、感染源は異なると考えられた。2例のHEV株はともに12年前に同県内の飼育ブタから検出された遺伝子型3型株の子孫と考えられ、このウイルスが宮崎県内で存続していることが証明された。1例は急性末梢性顔面神経麻痺を合併した。(著者抄録)

岐阜市近郊に在住で各々前医から異なる時期に肝障害で紹介受診した急性E型肝炎6例(男性5例、女性1例、年齢51〜71歳)について検討した。全例が異なる主訴で前医を受診し採血で肝障害を指摘された。当院初診時にIgA-HE抗体陽性で急性E型肝炎と診断し、後のHEV-RNA検査で確定診断した。1例は顕性黄疸を認め、PTが40%の重症例であったが、他の5例は黄疸を認めず、輸液等で回復した。問診で豚レバー・心臓を生で喫食1例、調理豚肉喫食3例、豚しゃぶしゃぶ喫食1例が判明したが、1例で感染の危険因子は認めなかった。凍結保存血清からHEVの塩基配列を決定して分子進化系統樹を作成した。遺伝子型は4型1例、3b型3例、3a型2例で、各々は系統樹上で全く近縁関係を示さなかった。4型の1例は愛知県内で捕獲のイノシシ肉喫食後の急性E型肝炎例から分離された株と99.1%の高い一致率を示し、他の5例では99%以上の相同性を持つ既報株は存在しなかった。

Aim: To characterize hepatitis E in Mie prefecture and to investigate whether raw pig liver sold as food in Mie is contaminated with hepatitis E virus (HEV) strains similar to those recovered from patients. Methods: Seventeen patients with sporadic acute hepatitis E treated from 2004 to 2012 were studied. A total of 243 packages of raw pig liver from regional grocery stores were tested for the presence of HEV RNA. The partial genomic sequences of human and swine HEV isolates were determined and subjected to the phylogenetic analyses. Results: The HEV isolates recovered from the 17 patients segregated into genotype 3 (n = 15) and genotype 4 (n = 2), and 15 genotype 3 isolates further segregated into 3e (n = 11) and 3b (n = 4). Pig liver specimens from 12 (4.9%) of the 243 packages had detectable HEV RNA. All 12 swine HEV isolates were grouped into genotype 3 (3a or 3b). Although no 3e strains were isolated from pig liver specimens, two 3b swine strains were 99.5-100% identical to two HEV strains recovered from hepatitis patients, within 412-nt partial sequences. Conclusion: The 3e HEV was prevalent among hepatitis E patients. HEV RNA was detected in approximately 5% of pig liver sold as food. The presence of identical HEV strains between hepatitis patients and pig liver indicated that pigs play an important role as reservoirs for HEV in humans in Mie. Further studies are needed to clarify the source of 3e HEV in the animal and environmental reservoirs.

2007年の三重県北中部地域16農場からの廃棄豚レバー計85個に由来するRNAをORF2領域の457塩基長を増幅しうるRT-PCR法に供し、既報のE型肝炎ウイルス(HEV)株と比較した。HEV RNAは2検体(swJ-Mie07-37L、swJ-Mie07-80L)が検出され、分子系統解析の結果、それぞれ3e/3sp株、3b/3jp株に属することが判明した。swJ-Mie07-80Lは、三重県内の急性E型肝炎例を含め、既報株との一致率は93.2%以下であった。一方、swJ-Mie07-37Lは、既報の3e/3sp株(三重県および愛媛県E型肝炎症例)と99.2%の一致率を示し、HE-JA10-1071、-0841、HE-JA12-0394、-0752、-0546、-0647とも98.3〜99.0%の高い相同性を示した。分子系統樹を作成したところ、swJ-Mie07-37Lはこれらの株と同一のクラスターを形成していた。三重県北中部地域で発生し続けてきたE型肝炎の主たる原因株に非常に近縁な株が、県内産豚にも感染していることが判明した。

69歳男。主訴は全身倦怠感であった。眼球結膜の黄疸と肝逸脱酵素・ビリルビン上昇を認め、IgA-E型肝炎ウイルス(HEV)抗体、IgM-HEV抗体、IgG-HEV抗体、HEV RNA陽性から急性E型肝炎と診断した。補液とグリチルリチン製剤にて第29病日に軽快退院した。患者の凍結保存血清からHEVのORF2領域の412塩基長の塩基配列を決定し、既報株の塩基配列とともに分子進化系統樹を作成した結果、4型愛知静岡株と100%のbootstrap値でクラスターを形成し、このクラスターに属する株との塩基配列の相同性は97.8%以上であった。発症前の3ヵ月に愛知県・岐阜県・静岡県で野生動物肉の喫食歴がなく、患者と生活・飲食をともにした者に肝炎を発症した者はなかったことから、4型愛知静岡株が野生動物以外にも広がり、その感染源が三重県に侵入していることが疑われた。

We investigated the migration patterns of hepatitis C virus (HCV) in China. Partial E1 and/or NS5B sequences from 411 volunteer blood donors sampled in 17 provinces and municipalities located in five large regions, the north-northeast, northwest, southwest, central south, and southeast, were characterized. The sequences were classified into eight subtypes ( 1a, n = 3; 1b, n = 183; 2a, n = 83; 3a, n = 30; 3b, n = 44; 6a, n = 55; 6n, n = 10; 6v, n = 1) and a new subtype candidate. Bayesian evolutionary analysis by sampling trees of the E1 sequences of the five major subtypes revealed distinct migration patterns. Subtype 1b showed four groups: one is prevalent nationwide with possible origins in the north-northeast; two are locally epidemic in the central south and northwest, respectively, and have spread sporadically to other regions; and the fourth one is likely linked to the long-distance dispersion among intravenous drug users from the northwest. Subtype 2a showed two groups: the larger one was mainly restricted to the northwest and seemed to show a trend toward migration via the Silk Road; the smaller one was geographically mixed and may represent descendants of those that spread widely during the contaminated plasma campaign in the 1990s. Subtype 3a exhibited three well-separated geographic groups that may be epidemically unrelated: one showed origins in the northwest, one showed origins in the southwest, and the other showed origins in the central south. In contrast, subtype 3b had a mixture of geographic origins, suggesting migrations from the southwest to the northwest and sporadically to other regions. Structurally resembling the tree for subtype 3a, the tree for subtype 6a showed four groups that may indicate migrations from the central south to southeast, southwest, and northwest. Strikingly, no subtype 6a strain was identified in the north-northeast.

薬物性肝障害診断時の項目にE型肝炎の除外は含まれていないが、IgA-HE抗体測定系保険収載後の2012年よりE型肝炎届出数は増加している現状がある。2003年〜2012年の期間に当院で経験したE型肝炎13例で、薬物性肝障害診断時のE型肝炎除外の必要性について検討した。E型肝炎12例の感染源は不明であった。E型肝炎マーカー未測定時、8例が薬物性肝障害と誤診され、薬物性肝障害例の11.6%を占めた。E型肝炎例はスコアリングシステムを使用時全例が5点以上となり、点数分布を薬物性肝障害例と比較しても有意差を認めなかった。従来指摘されている畜肉の摂取は13例中1例でのみであり喫食歴からE型肝炎感染を推測することは困難であった。正確な薬物性肝障害診断のため、現行の薬物性肝障害診断基準にE型肝炎マーカー、特に保険収載されたIgA-HE抗体価測定を加え、スコアリングの段階でE型肝炎の除外診断を行う必要があると考えられる。(著者抄録)

A 67-year-old male living in Tsu city, Mie prefecture, Japan was referred to our hospital for further examination of acute liver injury and was diagnosed as having clinical hepatitis E virus (HEV) infection in January 2010. The HEV strain (HE-JA11-1701) isolated from the patient belonged to genotype 3 and European-type subgenotype 3e. It was presumed that the patient had been infected from a wild boar (Sus scrofa leucomystax) because he consumed meat/viscera from a wild boar that he had captured himself as a hunter approximately 2 months before disease onset. A specimen of the boar meat/viscera that the patient had ingested was not available. However, the HE-JA11-1701 strain was 99.8% identical within the 412-nucleotide sequence of the open reading frame 2 region to a HEV strain (JBOAR012-Mie08) that had been recovered from a wild boar captured near the patient's hunting area in 2008. A phylogenetic analysis confirmed that the two HEV strains had a close genetic relationship and were segregated into subgenotype 3e, supported by a high bootstrap value of 99%. Of note, the HE-JA11-1701 and JBOAR012-Mie08 strains were remotely related to the 3e strains reported in Japan and European countries, with a nucleotide difference of 7.9-13.9%, reinforcing the uniqueness of the 3e strains obtained in the present study. These results strongly support our speculation that the patient developed acute hepatitis E via consumption of HEV-infected boar meat/viscera. Genetic analyses of HEV strains are useful for tracing infectious sources in sporadic cases of acute hepatitis E.

In this study, we characterized the full-length genome sequences of seven hepatitis C virus (HCV) isolates belonging to genotype 1. These represent the first complete genomes for HCV subtypes 1e, 1h, 1l, plus one novel variant that qualifies for a new but unassigned subtype. The genomes were characterized using 19-22 overlapping fragments. Each was 9400-9439 nt long and contained a single ORF encoding 3019-3020 amino acids. All viruses were isolated in the sera of seven patients. residing in, or originating from, Cameroon. Predicted amino acid sequences were inspected and unique patterns of variation were noted. Phylogenetic analysis using full-length sequences provided evidence for nine genotype 1 subtypes, four of which are described for the first time here. Subsequent phylogenetic analysis of 141 partial NS5B sequences further differentiated 13 subtypes (1a-1m) and six additional unclassified lineages within genotype 1. As a result of this study, there are now seven HCV genotype 1 subtypes (1a-1c, 1e, 1g, 1h, 1l) and two unclassified genotype 1 lineages with full-length genomes characterized. Further analysis of 228 genotype 1 sequences from the HCV database with known countries is consistent with an African origin for genotype 1, and with the hypothesis of subsequent dissemination of some subtypes to Asia, Europe and the Americas.

Nucleotide sequences of hepatitis E virus (HEV) isolates infecting wild boars in Mie prefecture, which is located in the central region of Japan and is far from the most prevalent regions of HEV infection in Japan, were determined and characterised. Among 144 serum samples of wild boars captured in Mie prefecture, 7 were positive for HEV-RNA. The nucleotide sequence of nearly the entire genome was determined for 4 of the 7 positive samples. Phylogenetic tree analyses indicated that 6 samples were subtype 3e and 1 was subtype 3a among the 7 isolates. We identified the indigenization of subtype 3e isolates in Japanese wild boars. Furthermore, 5 subtype 3e isolates were closely related and were located in the peripheral branch of subtype 3e isolates from European countries in the phylogenetic tree. The structure indicated that the ancestor of the 5 subtype 3e isolates originated in Europe. The phylogenetic structure and coalescent analyses suggested that the subtype 3e isolates entered Japan from Europe by importation of large-race pigs around 1966. The results also indicated that several lineages of subtype 3e expanded to a wide area of Japan around 1992 and 1 of the lineages was indigenized in wild boars in Mie prefecture between 1992 and 2009. The appearance of a wild boar cluster in the peripheral branch in the phylogenetic lineage may indicate the direction of gene flow of HEV subtype 3e from swine to wild boars. Clarification of the transmission direction or route should be helpful to prevent a future endemic or epidemic of HEV infection. (C) 2013 Elsevier B.V. All rights reserved.

74歳男性。糖尿病および慢性腎不全により血液透析を行っていた。今回、糖尿病に対しビルダグリプチン(VG)投与を開始後、腹部膨満感と便秘症状が出現、更に腹痛および吐気も伴った。画像所見にて小腸および大腸ガスと半結腸主体の便の停滞が認められたため、内服薬を中止し、絶飲食を行い、あわせて補腋を開始したところ、腹痛や腹満は消失し、排便回数や排便量が増加傾向となった。そこで、VG内服の再開を開始したが、腹部症状が増悪したため、再び絶飲食、内服薬中止、末梢輸液を行った。その結果、症状は改善し、経口摂取を再開した。尚、今までの経緯よりVG再開後に便秘症状が再発したことから、同薬剤が便秘の原因の被疑薬と考え、内服を中止したところ、腹痛・腹満・食事摂取量・排便回数・排便量・排便性状は安定した。

In Mie prefecture in Japan, 12 cases of sporadic hepatitis E occurred from 2004 to 2011. Mie prefecture is located in the central region of Japan, far from the most prevalent regions of hepatitis E virus (HEV) infection in Japan, the north and northeastern part. These 12 cases did not have any common risk factors of HEV infection. We analyzed the molecular epidemiology of the cases in Mie prefecture. We obtained the nucleotide sequences of the HEV strains and analyzed them with the sequences of other HEV strains by phylogenetic and coalescent analyses. Japan-indigenous genotype 3 HEV strains were divided into two major subtypes, namely, 3a and 3b; one minor subtype, 3e; and a few other unassigned lineages. The Japan-indigenous subtype 3e strains were closely related to European subtype 3e HEV strains and were comparatively rare in Japan; however, eight strains of the 12 cases we examined belonged to subtype 3e, indicating a close phylogenetic relationship, despite the lack of common risk factors. Coalescent analyses indicated that the Mie 3e strains seemed to have intruded into Mie prefecture about 10 years ago. Sporadic acute hepatitis E cases caused by the 3e strains occurred consistently from 2004 to 2011 in Mie prefecture. This is the first report of unexpected persistent occurrence of hepatitis by the European-type genotype 3 HEV, subtype 3e, in a country outside of Europe. Phylogenetic and coalescent analyses traced the history of the indigenization of the Mie 3e strains from Europe. Because hepatitis E cases caused by 3e strains are relatively rare in Japan, molecular evolutionary analyses of HEV infection in Mie prefecture is important for preventing a future hepatitis endemic or epidemic by 3e strains in Japan. (c) 2012 Elsevier B.V. All rights reserved.

Background: Since previous studies have investigated the population dynamics of Japan-indigenous genotype 3 hepatitis E virus (HEV) using virus sequences, more nucleotide sequences have been determined, and new techniques have been developed for such analysis. Aims: To prevent future hepatitis E epidemic in Japan, this study aimed to elucidate the cause of past HEV expansion. Methods: The epidemic history of Japan-indigenous genotype 3 HEV was determined using the coalescent analysis framework. Bayesian skyline plot (BSP) and Bayesian estimate of phylogeny with relaxed molecular clock models were calculated using Markov chain Monte Carlo sampling. Results: Japan-indigenous strains consist of New World strains (subtype 3a), Japanese strains (3b) and European strains (3e). The oldest lineage, 3b, appeared around 1929. Lineages 3a and 3e appeared around 1960. BSPs indicated similar radical population growth of the 3a and 3b lineages from 1960 to 1980. Conclusions: Population dynamics of the three lineages shared some common characteristics, but had distinguishing features. The appearance of 3a and 3e lineages coincides with the increase of large-race pig importation from Europe and the USA after 1960. The epidemic phase of 3a and 3b strains from 1960 to 1980 could be related to increased opportunity for HEV infection arising from large-scale pig breeding since 1960. Our observations revealed new findings concerning the close relationship between the epidemic history of Japan-indigenous genotype 3 HEV and the improvement of the Japanese pig industry. Infection control in pig farms should be an effective method of preventing HEV infection in humans.

2003年10月から2010年11月までの約7年間に6例の散発性E型肝炎症例を経験した。いずれの症例も幸い重症化せず軽快したが、HEVの遺伝子解析が可能であった5例のうち4例から3型の中でも我が国では稀な、ヨーロッパで分離される株に近縁なHEVが検出された。個々の症例間の関連は認められず、明らかな感染原因は不明であったが、分離株4株の類似性が高く、遺伝子配列の一致率はORF2領域の412塩基長の配列において99.3〜99.5%であった。これら4例の発生時期は2004年から2010年に及んだことから、三重県北中部では稀な3型(ヨーロッパ型)HEVの感染源が長期間に渡って維持されていることが推察された。感染源が特定されておらず、この型のHEVによる急性肝炎の特徴も不明であることから、今後も注意深い観察による実態把握と感染予防対策の構築が必要である。(著者抄録)

症例は54歳の男性。経皮内視鏡的胃瘻造設術(percutaneous endoscopic gastrostomy:PEG)が施行された後、脳血管障害後遺症のため他院に入院中であった。X線検査で上部食道に鋭利な人工歯根を有する局部床義歯を認め、胃穹窿部に1本の鋭利な義歯を認めたため紹介となった。内視鏡的静脈瘤結紮術用オーバーチューブとネット鉗子を用いることにより、重篤な合併症を発症することなく、内視鏡的に異物除去を行うことが可能であった。この方法は合併症の予防に有用で、かつ、安全であると考えられた。義歯を有するPEG後栄養管理中の症例においては、口腔ケアの際に義歯が不安定になっていないかどうかを定期的に確認し、義歯の誤飲を未然に防ぐ注意が必要である。(著者抄録)

20歳以下の若年でほぼ同時期に発症したHLA-B27陽性の脊椎関節炎(SpA)の姉妹例を報告した。症例1(二人姉妹の姉)、症例2(症例1の妹)、母方伯母に強直性脊椎炎(AS)の既往があり、2例とも20歳以下で臀部痛などの脊椎関節炎症状が出現し、HLA-B27は陽性であった。SpAのAmor診断基準はそれぞれ11点、10点であったことからSpAと診断され、非ステロイド系抗炎症薬、サラゾスルファジン投与により臨床症状とCRPは正常化した。本症例は女系家族集積性の極めて高いSpAの姉妹例で、ASを含むSpAがまれなリウマチ病態であるなかで、見落とされやすい女性症例に留意する必要性を示すものであり、女性SpA例の特徴を理解するうえで貴重な症例であった。

BSCガストロストミーシステム:BSC gastrostomy system(以下BSCGSと略す)は、ガイドワイヤーを用いずに胃瘻造設後のカテーテル交換を行うことができるバンパータイプ・ボタン型カテーテルキットである。今回BSCGSに改良が加えられたため、交換に要する時間や、バイタルサインの変化について、ガイドワイヤーを用いる同タイプのキットとの比較検討を行った。BSCGSでは、有意に交換時間が短縮され(p<0.01)、バイタルサインの変化に有意差は認めず、有用かつ安全と考えられた。(著者抄録)

難消化性デキストリン含有食品「健糖楽茶」のショ糖負荷試験による血糖値抑制効果について二重盲検クロスオーバー法で検討した。血糖値に異常がない健康被験者20例を対象とした。対照食品あるいは試験食品を速やかに摂取させ、6分後に150mLのショ糖液を速やかに摂取させた。血糖値のピーク値は試験食品群、対照食品群ともショ糖液摂取直後の30分に現れ、血糖値は45分で有意に試験食品群で抑制された。摂取後60分、90分、120分では対照食品群との有意差はなかった。AUCは有意に試験食品群で抑制された。インスリン値の経時変化は、対照食品群と試験食品群に有意差はなく、二元配置分散分析では摂取後時間にのみに有意差を認めた。対照食品群に比べて試験食品群でインスリン値が低値になることはなかった。対照食品群で、血糖値とインスリン値には比較的強い相関を認めた。試験食品及び対照食品を摂取することによる有害事象は認めなかった。

難消化性デキストリン含有食品「健糖楽茶」の反復摂取における安全性について検討した。1回1包、1日3回の試験食品を1ヵ月間摂取する過剰摂取試験を実施した。試験開始前、試験開始2週間後、4週間後、終了後2週間目に理学検査、血液及び尿検査を実施した。29例の、試験食品の平均摂取回数は80.2回、平均摂取率は95.4%と良好なコンプライアンスであった。摂取期間中の有害事象(愁訴)は摂取後2週間に多く発生したが、いずれも軽症で数日以内に解消した。摂取前の愁訴人数と近い人数であった。尿潜血陽性は一過性で、摂取前の陽性反応が継続的に発生しなかった。試験中の脱落例はなく、1ヵ月間過剰摂取試験における血液検査結果及び尿検査の結果では、特別な有意差を示す変動は観察しなかった。いずれかの検査において血糖値が110mg/dLを超えた境界型被験者の臨床検査値にも異状はなかった。安全性はヒト臨床試験で確認した。

我々は、経皮内視鏡的胃瘻造設術(以下PEGと略す)の術後早期の感染症を予防する目的で、オーバーチューブ(以下OTと略す)と胃壁固定具(以下GDと略す)を用い、その有用性と安全性について、検討を行った。OTとGDの併用は肺炎の発症率を有意に低下させた(p<0.05)。PEG施行時に、OTとGDを併用することは、術後早期の肺炎の発症を予防するうえで有用であり、胃壁固定時やOT挿入時に重篤な合併症も認めず、安全であると思われた。(著者抄録)

Aim: To study hepatitis C virus (HCV) selection and hypervariable region-1 (HVR1) evolution in a chimpanzee chronically infected with HCV-1 over 12 years after inoculation with a human factor VIII concentrate contaminated with HCV. Methods: From the inoculum, the earliest chimpanzee plasma and 12 annual plasma samples, HCV fragments including HVR1 were amplified followed by cloning and sequencing. Results: Five HCV subtypes - 1a, 1b, 2a, 2b, 3a - and multiple 1a strains were identified in the inoculum. Two 1a strains were found in the earliest chimpanzee sample, while a single HCV-1 strain was detected in the 12 annual samples. None of the chimpanzee sequences were identical to those found in the inoculum. Over 12 years, HVR1 patterns changed irregularly, but a few patterns showed identical nucleotide or amino acid sequences. In the last three years, the variety of HVR1 patterns decreased, while the proportion of major patterns increased. These corresponded to a higher virus load and a lower number of amino acid substitutions. Simultaneously, the HVR1 sequences became more similar to the consensus sequence of the 1a subtype. Conclusion: HCV selection was observed from the inoculum to the inoculated chimpanzee and from the early acute hepatitis to the persistent chronic infection. The selection occurred at three levels: among subtypes after transmission, among isolates during acute hepatitis and among quasispecies in chronic infection.

62歳女。特発性肺線維症(IPF)の増悪でメチルプレドニゾロンによる入院治療が行われていたが黒色嘔吐、黒色便も出現した。意識清明、眼瞼結膜軽度貧血を認めた。胸部聴診で軽度ラ音を聴取し、心窩部に軽度圧痛を認めたが、腹部は平坦、弾性軟で肝脾は触知せず、下肢に軽度浮腫を認めた。また神経学的異常所見は認めなかった。上部消化管内視鏡で胃上体大彎後壁より毛細血管拡張を認めた。病変は血管集簇に接して長径10mm、短径5mmの類楕円形の血管集簇が連続して存在し出血がみられたため出血性胃血管拡張と診断した。

Here, the complete genome sequences for three hepatitis C virus (HCV) variants identified from China and belonging to genotype 6 are reported: km41, km42 and gz52557. Their entire genome lengths were 9430, 9441 and 9448 nt, respectively; the 5' untranslated regions (UTRs) contained 341, 342 and 339 nt, followed by single open reading frames of 9045, 9045 and 9057 nt, respectively; the 3' UTRs, up to the poly(U) tracts, were 41, 51 and 52 nt, respectively. Phylogenetic analyses showed that km41 is classified into subtype 6k and km42 into subtype 6n. Although gz52557 clustered distantly with subtype 6g, it appeared to belong to a distinct subtype. Analysis with 53 and 105 partial core and NS5B region sequences, respectively, representing 17 subtypes from 6a to 6q and three unassigned isolates of genotype 6 in co-analyses demonstrated that gz52557 was equidistant from all of these isolates, indicating that it belongs to a novel subtype. However, based on a recent consensus that three or more examples are required for a new HCV subtype designation, it is suggested that gz52557 remains unassigned to any subtype.

Subtype 1b is the most common strain of Hepatitis C virus (HCV) in China. Here, the molecular epidemiology and epidemic history of this strain were investigated by conducting phylogenetic and population genetic analyses of El and NS5B gene sequences sampled from nine Chinese cities. The phylogenetic analysis indicated the presence of two clusters of Chinese strains that did not include reference strains from other countries, suggesting that these clusters represent two independent chains of HCV transmission within China. The remaining Chinese isolates were more closely related to reference strains from other countries. The date of origin and past population dynamics of the two groups were investigated using a new population genetic method, the Bayesian skyline plot. The estimated dates of origin of both groups coincide with the period of the Chinese 'Cultural Revolution' during the years 1966-1976. Both groups grew at a rapid exponential rate between similar to 1970 and similar to 1990, after which transmission slowed considerably. Possible explanations for the groups' fast spread and subsequent slowdown are discussed, including parenteral transmission by unsafe injection, iatrogenic transmission by infected blood or blood products and improvements in blood safety since 1990. These results shed light on HCV transmission in China and may help to predict the future burden of HCV-related disease in the country.