노로바이러스감염관리

가톨릭관동의대이혁민

Cause of acute gastroenteritis• Virus : most common

‒ Norovirus, rotavirus, adenovirus, astrovirus

‒ Sapovirus, coronavirus, torovirus, picobirnavirus, Aichi virus, etc

• Bacteria

‒ Salmonella, Shigella, campylobacter

‒ EHEC, ETEC

‒ S.aureus

‒ C. difficile: Healthcare-associated

• Parasite, protozoa

‒ Giardia, Entamoeba

‒ Cryptosporidium

• Non-infectious causes: toxins, food allergy, heavy metals, antibiotics, etc

• Unknown : ~50%

Positive specimens

(N)

Total specimens(N)

Isolated rate(%)

Bacteria 5종 54 1,871* 2.9%

Viruses 5종 776 1,871 41.5%

Total 830 1,871 44.4%

(질병관리본부, 2008.4-2010.3, n=1,871)

Etiologic agent of gastroenteritis(Korea, 2008.4-2010.3)

The distribution of bacteria

(질병관리본부, 2008.4-2010.3, n=1,871)

Salmonella spp.

61.1%

Campylobacter spp.

25.9%

ETEC9.3%

EHEC1.9% Shigella spp.

1.9%

Salmonella spp.

Campylobacter spp.

ETEC

EHEC

Shigella spp.

Salmonella and Shigella spp.

Short survival period: 1 day – 4 weeksHigh infective dose: 105 CFU

Salmonella spp.

Shigella spp.

Moderate survival period: 2 days – 5 months High infective dose: 180 CFU

Kramer A. et al, BMC Infect Dis 2006; DAVID L. S., Clin Microbiol Rev 1995

Patient infection control

The distribution of viruses

(질병관리본부, 2008.4-2010.3, n=1,871)

Rotavirus42.8%

Norovirus43.0%

Adenovirus11.4%

Astrovirus2.3%

Sapovirus0.4%

Rotavirus

Norovirus

Adenovirus

Astrovirus

Sapovirus

Norovirus

• Non-enveloped single-stranded RNA virus

• Epidemiology

– 18% of all cases of acute gastroenteritis worldwide

– 90% of epidemic nonbacterial outbreaks of gastroenteritis

– 50% of all foodborne outbreaks of gastroenteritis in the US

– 267 million infections per year

– Over 200,000 deaths per year: Infants and elderly

• Five genogroups

– GI and GII: The most prevalent genogroups in human infection

– GIII: Bovine infection

– GV: Mice infection

Clinical manifestations of norovirus

• General characteristics

– Incubation period: 12-48 hrs

– Symptoms: Nausea, forceful vomiting, watery diarrhea

abdominal pain, mild fever, body ache (Stomach flu)

– Self-limiting in a few days

– Sometimes severe infection in infant and elderly patients

• Incomplete and temporary immunity to norovirus

– Complete loss of immunity in 8 weeks to 6 months

– Recurrent infection of same strains or heterologous strains

Table Transmission and epidemiology of the major gastroenteritis viruses

Virus Mode of transmission Target population Occurrence

RotavirusFecal-oral, ?respiratory,

?food and waterChildren <5 yrs old (peak activity at 6 mo to 2 yr)

Fall/winter months in temperate climates, year round in tropical regions

NorovirusFecal-oral, foods, water,

?respiratoryAll age groups

Winter peak, year-round outbreaks common in variety

of settings

Sapovirus Fecal-oral, ?respiratoryMainly children (primarily

infants and toddlers), less so in adults

Sporadic year round, outbreaks occur

Enteric Adenovirus Fecal-oral, ?respiratoryMainly infants and young

children < 5 yrs oldSporadic year round,

outbreaks occur

AstrovirusFecal-oral, water,

?respiratory Mainly young childrenSporadic year round,

outbreaks occur

Table Selected clinical features of the major gastroenteritis viruses

Virus Clinical significanceIncubation

(days)Vomiting

(days)Diarrhea

(days)

Virus shedding

(days)

RotavirusAcute severe dehydrating gastroenteritis, hospital-acquired infections (HAI), subclinical infections occur

1-2 2-3 5-8 8-10

Caliciviruses

Noroviruses: moderate to severe AGE, HAI, prolonged shedding and chronic disease in immunocompromised patients, subclinical infections occur

Sapoviruses: mild to moderate gastroenteritis, subclinical infections occur

1-2 0.5-1 1-2 1-21

Enteric Adenovirus

Moderate to severe gastroenteritis, HAI, persists in immunocompromised patients

8-10 2-3 4-12 8-13

AstrovirusMild to moderate gastroenteritis, subclinical infections

occur1-2 1-4 1-4 8-10

Pandemic outbreak of norovirus

• Influenza 와비슷한역학: 2-3년마다새로운 GII.4 variants가나타나서epidemic을일으킴• Pandemics : 3개이상의대륙• US 1995/96 in late 1990s• Farminton Hills virus in 2002• Hunter virus in 2004• Den Haag 2006b virus in 2007-2008• New Orleans virus 2009 in 2009-2012• GII.4 Sydney 2012

• Localized epidemics in specific region, but not global• Japan 2001, Henry 2001, Asia 2003, Yerseke 2006a, Osaka 2007,

Apeldoorn 2008

Pandemics of influenza A virus

• 1918 Spanish flu H1N1

• 1957 Asian flu H2N2

• 1968 Hong Kong flu H3N2

• 2009 novel flu H1N1 (Mexico)

Korean Food and Drug Administrationhttp://www.mfds.go.kr/fm/index.do?nMenuCode=79

Healthcare Bigdata Hub

1667

20172107

2814

1726

0

500

1000

1500

2000

2500

3000

2011 2012 2013 2014 2015

Special characteristics of norovirus in infection control

• Highly contagious virus (Infective dose < 10)– Ingestion of contaminated food or water– Direct contact with infected person: 109-12 particle/1g of feces– Surface or food contamination by direct contact or aerosolization

(100 million particle/1g of dried vomitus)

• Viral shedding: from before symptom onset to 2 weeks

– 30% of patients Asymptomatic

• Stable in environment

– Hard surface: several weeks

– Fabric surface: 12 days

– Water: Several months - years

• Stable to some kinds of antiseptics

J Infect Dis 2014

Blaney DD, et al. Am J Infect Control 2012Steinmann J, et al. Antimicrob Resist Infect Control 2013

Zheng DP, et al. J Clin Microbiol 2010

Hall AJ, et al. MMWR 2014

Barclay L, et al. Clin Microbiol Infect 2014

Infection control of Norovirus

Infection control measures suggested

• Contact precautions

– Patient isolation and cohorting

– A minimum of 48 hours after resolution of symptoms

• Enhanced hand hygiene

– Wash with soap and water for 20 seconds

– Alcohol-based hand sanitizers: Ineffective (Non-enveloped virus)

• Environmental infection control measures

– Chemical cleansing (Chlorine-based disinfectant)

• Exclusion of ill staff from work for a minimum of 48 hours after symptom resolution

• Surveillance for new and resolving cases

http://www.cdc.gov/hai/pdfs/norovirus/NoroVirus-Gen508.pdf

Patient isolation/Cohorting

Hand hygiene

환자이송및병동폐쇄

의료기관조리사및배식원

진단

개인보호장구

환경소독

직원관리

방문객관리

교육

능동적감시 (Active case-finding)

소통및고지

Kaplan criteria

• Vomiting in more than half of symptomatic cases

증상이있는환자의절반이상이구토

• Mean (or median) incubation period of 24 to 48 hours

평균또는중간잠복기 24-48시간

• Mean (or median) duration of illness of 12 to 60 hours

이환기간 12-60시간

• No bacterial pathogen isolated in stool culture

변배양에서장염세균음성

Diagnostic method

Kaplan criteria EIA/ELISA EM NASBA

Sensitivity 68 31-90 24-58 100

Specificity 99 65-100 98-99 50

PPV 97 52-100 88-94 -

NPV 82 56-97 - -

• Reference method: PCR

결론

• 노로바이러스국내감염흔함

• 노로바이러스는주요의료관련감염원인

• 비누를사용한손씻기시행

• 격리또는코호트운영 (증상소실후 48시간까지)

• 환경관리

• 적절한진단법사용 (Kaplan method)