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

Norovirus & Sapovirus

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)

Characteristics Caliciviridae, single stranded positive- sense RNA virus Small, round viruses, 35 nm in size, no envelope 7.5-7.7 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)

Main Symptom

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.

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

Transmission

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

Antigenicity of NoV

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

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

Laboratory Surveillance < EnterNet-Korea, 2016 >

Prominent Norovirus <K-EnterNet / K-CaliciNet >

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

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

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

Variation of NoV GII.17 < Eurosurveillance, 2015 >

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

Return of GII.4

Astrovirus

Antigenicity of Astrovirus

Epidemic of Astrovirus

Outbreak of Astrovirus

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