Jaundice hemorrhagic leptospirosis - jaundice hemorrhagic leptospirosis

Japanese: 黄疸出血性レプトスピラ病 - おうだんしゅっけつせいれぷとすぴらびょう

It is an acute infectious disease whose main symptoms are jaundice, bleeding, and proteinuria, and is the most severe form of leptospirosis, which can result in death. In 1886, German physician Adolf Weil (1848-1916) first reported four cases, but patients were soon found all over the world and the disease was called Weil's disease. In 1915 (Taisho 4), the pathogen was discovered by Inada Ryukichi and Ido Yasushi, and it was named icteric hemorrhagic spirochetosis, but it was later discovered to be leptospira, and icteric hemorrhagic leptospirosis became the official name of the disease. The pathogen of leptospirosis is collectively called Leptospira interrogans , and each leptospira is called its serovar. Jaundice hemorrhagic leptospirosis is caused by L. interrogans serovar icterohaemorrhagiae , and is also caused by the Copenhagen type (serovar copenhageni ). House mice and voles have long been known to be reservoirs of the pathogen, but in recent years, dogs, cats, cows, horses, and pigs have also been reported to be reservoirs. Most of the infected people work in sewage construction, farm work, and kitchens, all of which are related to mice. The disease occurs throughout the year, but is most common from summer to autumn, and outbreaks often occur in large groups in rural areas.

[Noriaki Yanagishita]

Symptoms

The incubation period is 4-14 days. Infection is mainly through the skin, but oral infection can also occur. The course of the disease after onset is divided into three stages. The first stage is a 2-5 day febrile stage, during which the patient suddenly develops a fever of 39-40°C or higher, and symptoms include headache, lower back pain, joint and muscle pain in the limbs (especially when the calf muscle is squeezed, it is extremely painful), fatigue, vomiting, and a condition called pink eye, in which the conjunctiva becomes congested. The second stage is the jaundice stage, in which 50-70% of patients develop jaundice. Renal disorders such as oliguria and anuria occur, and bleeding tendencies such as pinpoint bleeding on the skin and mucous membranes, nosebleeds, gingival bleeding, hematemesis, hemoptysis, bloody stool, and uterine bleeding become prominent. Circulatory failure (low blood pressure, irregular heartbeat, etc.) also appears. The third stage is the convalescent stage, which usually begins towards the end of the second week after the onset of the disease. Weakness is usually evident, and in severe cases recovery can take several months. Complications due to mixed infections (such as parotitis and iritis) can also occur. Sequelae include anemia and impaired vision due to vitreous opacity, which can appear between one month and six months after recovery from Weil's disease. In addition, the disease can take a milder or incomplete form, with some symptoms missing, or meningitis as the main symptom.

[Noriaki Yanagishita]

Treatment

It is one of the diseases that requires early detection and early treatment, but in the early stages of the disease, there is no sense of seriousness and it is difficult to keep at rest, so hospitalization may be required as soon as the disease is discovered. Antibiotics are used early, but once the disease develops, it progresses quickly and even a half or one day delay in starting treatment can lead to severe illness. If proper treatment is administered within five days of the onset of the disease, the mortality rate is less than 10%, but after that, it can reach 20-30%. Streptomycin is the most effective, and the earlier treatment is started, the greater the effect. Adrenal cortical hormones are also used in severe cases, which are common among the elderly.

[Noriaki Yanagishita]

prevention

The pathogen is excreted in the urine of patients, and in nature the urine of infected livestock and rats is also dangerous. Therefore, in endemic areas, people must use rubber gloves and boots to avoid contact with water from rice paddies and ditches, and kitchens must be kept clean to prevent food from being contaminated by rats. In areas where the disease is prevalent, preventive vaccinations and oral administration of streptomycin are also carried out.

[Noriaki Yanagishita]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

Japanese:

黄疸、出血、タンパク尿を主要徴候とする急性伝染病で、レプトスピラ病のうち、死亡例もあるもっとも重症型の疾患である。1886年ドイツの医師ワイルAdolf Weil（1848―1916）が初めて4例を報告したが、まもなく全世界で患者がみつかり、ワイル病とよばれた。1915年（大正4）稲田竜吉(りゅうきち)、井戸泰(やすし)によって病原体が発見され、黄疸出血性スピロヘータ症と命名されたが、のちにレプトスピラであることがわかり、黄疸出血性レプトスピラ症が正式の病名になった。レプトスピラ病の病原体は一括してレプトスピラ・インテルロガンスLeptospira interrogansとよばれ、それぞれのレプトスピラはこれに血清型（serovar）を続けてよばれる。黄疸出血性レプトスピラはL. interrogans serovar icterohaemorrhagiaeであり、ほかにコペンハーゲン型（serovar copenhageni）によるものもある。病原体の保有動物は昔からイエネズミやハタネズミが知られているが、近年、イヌ、ネコ、ウシ、ウマ、ブタなどの保有も報告されている。罹患(りかん)者は下水工事や農作業、あるいは調理場などで働く職業の人に多く、いずれもネズミとの関係が認められる。年中発生するが、とくに夏から秋にかけて多く、農村などではしばしば集団的に多発する。

［柳下徳雄］

症状

潜伏期は4～14日。経皮感染がおもであるが、経口感染もある。発病後の経過は3期に分けられる。第1期は2～5日間の発熱期で、突然39～40℃以上に発熱し、頭痛、腰痛、四肢の関節痛や筋痛（とくに腓腹(ひふく)筋を握られると、ひどく痛む）のほか、倦怠感(けんたいかん)や嘔吐(おうと)などがあり、ピンク・アイともよばれる眼球結膜の充血がみられる。第2期は発黄期で、50～70％に黄疸がみられる。乏尿や無尿などの腎(じん)障害をおこし、皮膚や粘膜の点状出血をはじめ、鼻血、歯肉出血、吐血、喀血(かっけつ)、下血、子宮出血などの出血傾向が著明となる。また、循環不全（血圧低下や不整脈など）が現れる。第3期は回復期で、発病後第2週の終わりごろから始まることが多いが、普通は衰弱が目だち、重症例では回復に数か月かかることもある。また、混合感染による合併症（耳下腺(じかせん)炎や虹彩(こうさい)毛様体炎など）がみられる。後遺症には貧血や硝子体(しょうしたい)混濁による視力障害があり、ワイル病の治癒後1か月から半年の間にみられる。このほか、一部の症状を欠く不全型や軽症型の経過をとることもあり、髄膜炎症状を主徴とすることもある。

［柳下徳雄］

治療

早期発見、早期治療が望まれる疾患の一つであり、病初期には重症感がなくて安静を守りにくく、発見しだい入院ということもある。早期に抗生物質を用いるが、いったん発病すると経過が早く、半日あるいは1日の治療開始時期の遅れによっても重症となりやすい。発病後5日以内に適正な治療が行われると致死率は10％以下であるが、それ以後になると20～30％にもなる。ストレプトマイシンがもっとも有効で、早期に開始するほど効果が著しい。老人に多くみられる重症患者には副腎皮質ホルモンも併用する。

［柳下徳雄］

予防

病原体は患者の尿とともに排出されるほか、自然界では罹患した家畜やネズミの尿も危険である。したがって流行地域では、水田やどぶの水には接触しないようゴム手袋や長靴を用いたり、ネズミに食物を汚染されないよう台所を整備する必要がある。発生の濃厚な地域では予防ワクチンの接種やストレプトマイシンの予防内服も行われる。

［柳下徳雄］

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