An outbreak of norovirus gastroenteritis occurred among 25 Taiwanese tourist groups returning from Korea between December 24, 2013 and January 13, 2014. The Taiwan and Korea Centers for Disease Control collaborated to investigate the outbreak. They conducted interviews of affected tourists, identified the suspected restaurant, and tested stool and water samples. Testing found two genotypes of norovirus in stool samples and in the water source used by the implicated restaurant. The outbreak was traced to contamination of the restaurant's water supply.

1. Ying-Shih Su1, Hao-hsin Wu1, Wan-Chin Chen1, Yi-Chun Lo1, Hyung-min Lee2, Donghyok Kwon2
1. Taiwan Centers for Disease Control 2.Korea Centers for Disease Control and Prevention
1/6
Result
Taiwanese Media
reported the events.
TCDC initiated
the investigation.
KCDC got the
information and
performed epidemic
investigation.
Norovirus was found
in tourists’ stool
Hong Kong media:
Clusters of diarrhea
in travelers that
recently visited
Korea.
Confirm food items
consumed Design
questionnaire
Interviewed Sampled touristsTCDC conducted
active case finding
at the airport
quarantine and
collected tourists
information.
The suspected
Restaurants was
identified by
comparing
itineraries of
tour groups.
Restaurant X was
requested for
suspension. No
more cases after
1/7.
Timeline
 Norovirus gastroenteritis outbreak identified among 25
Taiwan tourist groups returning from Korea from
December 24, 2013 to January 13, 2014
 TCDC collaborated with KCDC in investigating the
outbreak.
Background
Active Case Finding
Health advisory on Jan 2, 2014, mandated travel agents to report
gastroenteritis occurring among tour groups in Korea
Case-control study
*.Purposive Sampling of 5 tour groups for questionnaire interviews
*. Case definition: Acute onset of diarrhea or vomiting during December 24,
2013 to January 12, 2014 in a group tourist while traveling in Korea
Laboratory investigation
*. Rectal swabs and stool samples from tourists and food handlers
*. Water source from the implicated restaurant
*. Tested for bacteria culture and norovirus & rotavirus PCR
Active case findings Lab. results
Negative for bacteria pathogen (0/44)
Case-control study
Table 1. Analysis of risk factors Table 2. Genogroup of norovirus
(From stool)
*. Two Taiwanese tourists identified with 2
genogroups of norovirus
**. Norovirus(genotype GI.9, GII.4, GII.6)
detected in water source used in Restaurant X
 Source of the outbreak : contamination of water
source of the restaurant
 Prompt international cooperation and information
sharing were key to control and detection outbreak
Division of Epidemic Intelligence Service, Korea
Centers for Disease Control and Prevention
Health departments in Taiwan and Korea that
investigated the outbreak.
Conclusion
AcknowledgementMaterial & Methods
Results
12/27
36 Taiwanese
tourists had
diarrhea and
vomiting during
travel in Korea
1/1
Public health
messaging to
passengers in
inbound flight
from Korea
E-mail
communication
between TCDC
and KCDC
initiated
Menu of
Restaurant X
was shared by
KCDC.
12/28 12/29 12/30 12/31 1/2 1/3 1/4 1/5
1/7 1/8 1/9
Further information
E-mail address : sih0818@cdc.gov.tw
URL: http://goo.gl/jR1RWT
Outbreak of Norovirus Gastroenteritis among Overseas Group Tourists
Get the information
through social media
Korea CDC
(KCDC)
Taiwan CDC
(TCDC)
Restaurant
X food
handler
Taiwan
Tourist
(TCDC)
Taiwan
Tourist
(KCDC)
No. of tested 2 31 12
No. of positive 2 18 10
GI
Gl.2 1
GI.8
GI.9 3
GI.12 2
GI.14 1
Other GI 1 1
GII
GII.4 1 5 5
GII.5 4
GII.6 7 2
Other GII 1
2013 2014
Case Control Odds ratio 95%CI
Water 22/28 6/7 0.6 (0.06, 6.1)
Romaine 36/57 10/13 0.5 (0.12, 2.08)
Bean curd 8/34 0/8 Undefined Undefined
Soya-bean sprout 24/54 3/9 1.6 (0.36, 7.07)
Korean Kimchi 44/56 8/13 2.3 (0.63, 8.29)
Kelp 22/27 5/6 0.9 (0.08, 9.28)
Tempura 11/28 3/6 0.6 (0.11, 3.80)
Soup 51/56 12/12 0 Undefined
Rice 52/57 10/11 1.0 (0.10,9.87)
Drinks 35/46 6/8 1.1 (0.18,6.02)
Pickled radish 12/28 3/7 1 (0.18,5.33)