国立感染症研究所

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The topic of This Month Vol.41 No.3(No. 481)

Clostridioides difficile infection in Japan

(IASR Vol. 41 p35-36: March, 2020)

Clostridioides difficile infection (CDI)

    Clostridioides (Clostridium) difficile is an obligate anaerobic Gram-positive spore-forming bacillus. Toxins produced by the organism include toxin A, toxin B, and binary toxin.

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The topic of This Month Vol.41 No.2(No.480)

Acute Flaccid Paralysis in Japan as of December 2019

(IASR Vol. 41 p17-18: February, 2020)

 Acute flaccid paralysis (AFP) is medically a broad term for disorders presenting with acute flaccid motor paralysis of the extremities (see p. 19 of this issue). AFP develops when the anterior horn cells of the spinal cord, along with the peripheral nerves or muscles, are damaged. Typical diseases causing AFP include Guillain-Barré syndrome (GBS), acute poliomyelitis (polio), and acute flaccid myelitis (AFM).

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The topic of This Month Vol.41 No.1(No.479)

Syphilis, Japan

Syphilis is an infectious disease caused by the Treponema pallidum subspecies pallidum. T. pallidum is a spirochete bacterium sized 0.1-0.2 µm in diameter and 6-20 µm in length. It has active motility and can be observed microscopically by staining or dark field microscopy. The mechanism of pathogenicity is poorly understood because it cannot be cultivated in vitro. Treponema includes species and subspecies that do not cause sexually transmitted infections, but recently, the T. pallidum subspecies endemicum (bejel) was first reported in Japan as a sexually transmitted disease (see p. 4 of this issue).

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The topic of This Month Vol.40 No.12(No.478)

Rotavirus, from September 2004 to August 2019, Japan

Rotavirus is a double-stranded RNA virus of 11 segments categorized into the genus Rotavirus belonging to the family Reoviridae. Rotavirus has no envelope and is classified into nine species (group A to I). The rotaviruses that have been reported to infect humans are mainly groups A and C, and epidemics among humans are mostly caused by group A. Rotavirus is a major cause of acute viral gastroenteritis in infants, and the majority of people are believed to have experienced infection at least once by 5 years of age. The virus is transmitted via the fecal-oral route, and usually with an incubation period of 2-4 days, causes symptoms such as diarrhea, vomiting, and fever. There is no specific therapy, and symptomatic treatments, such as infusion and oral rehydration, are performed. Although patients usually recover within a week, dehydration is often more severe than in other types of viral gastroenteritis. Convulsion associated with gastroenteritis is one of the complications, which is characterized by a cluster of convulsions 1-6 days (average 2.3 days) after acute gastroenteritis onset (see p. 209 of this issue). Less frequent complications include renal or hepatic failure and encephalitis/encephalopathy. Many of the severe cases are reported in children at primary infection during the period from 6 months to 2 years old. Treatment is performed according to the level of complication.

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Clostridium difficile surveillance in England

(IASR Vol. 41 p39-41: March, 2020)

From 2002, the emergence of a previously uncommon but more virulent strain, known as Clostridium difficile North American pulsed field type 1 (NAP1) or ribotype 027, fundamentally changed the epidemiology of C. difficile infection (CDI). These marked changes in epidemiology occurred first in North America and then in Northern Europe.1,2 In 2007-08, more than 55 000 CDI cases were reported in England, of which almost a quarter were in younger people who had previously not been considered to be at high risk for this antibiotic associated infection. Furthermore, the number of death certificates including the term ‘C. difficile’ increased each year in England and Wales, from 2238 in 2004 to 8324 in 2007.3

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The topic of This Month Vol.40 No.11(No.477)

Influenza 2018/19 season, Japan

(IASR Vol. 40 p177-179: November, 2019)

The 2018/19 influenza season (from week 36 in September 2018 to week 35 in August 2019) was characterized by the predominance of the influenza A/H1pdm09 subtype in the beginning, followed by the AH3 subtype and B/Victoria lineage from week 10 in 2019.

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The topic of This Month Vol.40 No.10(No.476)

HIV/AIDS in Japan, 2018

(IASR Vol. 40 p163-164: October, 2019)

HIV/AIDS surveillance in Japan started in September 1984. It was conducted under the AIDS Prevention Law between February 1989 and March 1999, and has been operated under the Infectious Diseases Control Law since April 1999. Under the law, physicians must notify all diagnosed cases (see http://www.niid.go.jp/niid/images/iasr/34/403/de4031.pdf). The data in this article were derived from the annual report of the National AIDS Surveillance Committee for the year 2018 (published by the Tuberculosis and Infectious Diseases Control Division, the Ministry of Health, Labour and Welfare (MHLW), http://api-net.jfap.or.jp/status/index.html).

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The topic of This Month Vol.40 No.9(No.475)

Hepatitis A in Japan between 2015 and March 2019

(IASR Vol. 40 p147-148: September, 2019)

Hepatitis A is an acute infectious disease caused by the hepatitis A virus (HAV), which belongs to the genus Hepatovirus of Picornaviridae. There is only one known serotype, which is classified into 6 genotypes, Ⅰ-Ⅵ. Viruses of genotypes Ⅰ to Ⅲ are detected in humans, with each genotype further divided into subgroups A and B. HAV is transmitted through the ingestion of contaminated food or water, or by direct contact with an infected person. In devel-oped countries with improved hygienic environments, such as water and sewage systems, large-scale outbreaks of hepatitis A are rare, but they have been reported among men who have sex with men (MSM) and persons who inject drugs (PWID).

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The topic of This Month Vol.40 No.8(No.474)

Rubella and congenital rubella syndrome in Japan as of May 2019

(IASR Vol. 40 p127-128: August, 2019)

Rubella is an acute infectious disease caused by the rubella virus, and the major clinical symptoms are rash, fever, and lymphadenopathy.  Rubella virus infection of pregnant women may result in prenatal transmission to the fetus and the birth of an infant with congenital rubella syndrome (CRS), which manifests as varying symptoms, including heart defects, hearing loss, and cataracts.  It may lead to death in cases associated with complications such as severe heart defects (see p. 129 of this issue).

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The topic of This Month Vol.40 No.7(No.473)

Severe fever with thrombocytopenia syndrome (SFTS) in Japan, as of June 2019

(IASR Vol. 40 p111-112: July, 2019)

Severe fever with thrombocytopenia syndrome (SFTS) was designated as a Category IV infectious disease under the Infectious Diseases Control Law on March 4, 2013 (see http://www.niid.go.jp/niid/images/iasr/35/408/de4081.pdf for notification criteria), and any physician who diagnoses SFTS is required to notify a local health center within 24 hours.  In many cases, SFTS is a tick-borne infection.  The causative virus was classified into the Genus Phlebovirus, Family Bunyaviridae, and was renamed “Huaiyangshan banyangvirusof Banyangvirus Genus of Phenuiviridae Family by the International Committee on Taxonomy of Viruses (ICTV) in 2018.  However, as it is widely referred to as the SFTS virus (SFTSV) in Japan and abroad, SFTS and SFTSV are used for the name of the disease and the virus, respectively, in this article.  SFTS was first reported in 2011 by Chineses researchers and was subsequently confirmed to be endemic to Japan and South Korea.  The incubation period is 5 to 14 days, and the major signs/symptoms in the early phase of the disease are fever, gastrointestinal symptoms, headache, and myalgia, which further associate with neurological symptoms (e.g., impaired consciousness) and bleeding symptoms (e.g., gingival bleeding and bloody diarrhea).  Physical examination may reveal superficial lymph node enlargement and epigastric tenderness.  Blood tests demonstrate leucopenia and thrombocytopenia, and increased AST, ALT, and LDH levels are observed by biochemical testing.  In surviving patients, symptoms usually improve in approximately one week after onset and resolve after approximately two weeks.  On the other hand, in fatal cases, multiple organ failure due to pathological conditions, such as respiratory and circulatory failure, and disseminated intravascular coagulation (DIC) is observed.

Copyright 1998 National Institute of Infectious Diseases, Japan

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