1. Molecular epidemics of Norovirus related Outbreak in Korea
- Current Trend of Norovirus Outbreak -
Deog-Yong Lee, Ph.D/D.V.M
Korea Centers for Disease Control and Prevention

2. Norovirus & Sapovirus

3. Disease Burden
Burden of Norovirus in the United States. Estimates of the annual number of illnesses and associated outcomes for norovirus disease in the U.S., across all age groups. Lifetime risks of disease are based on a life expectancy of 79 years of age. Ranges represent point estimates from different studies, not uncertainty bounds. (US CDC)

4. Characteristics
Caliciviridae, single stranded positive- sense RNA virus
Small, round viruses, 35 nm in size, no envelope
kb mRNA sense genome
Particle is made up of only 2 proteins (VP1, VP2)
No cell culture model or animal model
Stable outside the host (environmental contamination)

5. Main Symptom

6. Clinical Symptom Clinical Features - Incubation period: 12-48hr
: acute onset, non-bloody diarrhea, vomiting, nausea, and abdominal craps
- Resolve 1-3days without treatment
: 10% of medical attention
- Shed primarily in the stool, in vomitus (average 4 weeks, peak 2-5days)
- Protective immunity is complex and incomplete.

7. Epidemics Transmission Infectious dose: 18 viral particles
* 5 billion infection dose/g of feces during peak sheds
Human only reservoir for human infection
: person to person, food-borne, water-borne
Sporadic Cases
Twenty-one million illness by Norovirus/year, US
Severity
: 10-15% of severe patients in child ages <5 year
: 9-15% of mild & moderate, all ages

8. Transmission

9. Classification ▶ Norovirus classification ▶ Reference
1. GI 14, GII 17 (Kageyama et al., 2004)
2. ORF2 - GI 8, GII 21
ORF1 - GI 14, GII 29 (Maria et al., 2013)
3. GI 9, GII 22 (Annelies et al., 2013)
▶ Reference
Proposal for a unified norovirus nomenclature and genotyping, Annelies Kroneman et al., 2013

10. Antigenicity of NoV

11. GII.4 Sydney variant
< Data from Allen et al., 2014 & Debbink et al, 2013 >

12. Lab. Surveillance System
Pulse-Net
Salmonella spp.
Pathogenic E. coli
EHEC, ETEC, EPEC, EIEC
Shigella spp.
Vibrio parahaemolyticus
Campylobacter spp.
S. aureus
Cl. perfringens
B. cereus
L. monocytogenes
Y. enterocolitica
Calici-Net
Norovirus
Rotavirus
Enteric adenovirus
Astrovirus
Sapovirus
Bacteria
Virus
Pathogen Resources
Characteristic Data Base
Investigation epidemics
- place, time(year, month)
Respon. Imported Pathogens
(EHEC O104, Shigellosis etc)
Food & Water-borne Lab. Surveillance
EnterNet-Korea
Investigation of contamination source

13. Laboratory Surveillance
< EnterNet-Korea, 2016 >

14. Prominent Norovirus
<K-EnterNet / K-CaliciNet >

15. Cluster of NoV GII.4 variant
Hunter
2006b
Sakai
2008
2009(10)
2012(sydney)
Farmington
Henry
US95/96
Outlyer
Bristol
Cairo

16. Expect. of GII.4 variant
< Osong Public Health Res Perspect 2015, 6(5) >

17. Outbreak by NoV GII.17
< Osong Public Health Res Perspect 2017, 8(1) >

18. Variation of NoV GII.17
< Eurosurveillance, 2015 >

19. Next Expected Variant ?
Return of GII.4 as a New variant?

20. Return of GII.4

21. Astrovirus

22. Antigenicity of Astrovirus

23. Epidemic of Astrovirus

24. Outbreak of Astrovirus

25. The End
It should be continued to investigate the change of genotype and appearance of variants