Jpn. J. Infect. Dis., 58, 2005

Laboratory and Epidemiology Communications

Norovirus Gastroenteritis in Kanagawa Prefecture in December 2004
Yumiko Furuya*, Takashi Katayama, Takanori Takahashi and Takayasu Nikkawa
Department of Biology, Kanagawa Prefectural Institute of Public Health, Kanagawa 253-0087, Japan
Communicated by Tatsuo Miyamura(Accepted October 14, 2005)
There were 9 cases of gastroenteritis outbreaks caused bynoroviruses (NVs), including 4 foodborne cases in restaurants and a hotel (Table 1) (1) and 5 cases in welfare facilities
and hospitals (Table 2) (2,3), in December 2004 in Kanagawa
Prefecture, excluding the large cities of Yokohama, Kawasaki,

Yokosuka and Sagamihara.
Cases 1 to 4 (Table 1) were considered to be foodborne;
the patients attended the same dinner party and had the samedishes, and the onset of the cases was almost simultaneous.
However, in these cases, because the incriminated foodstuffs
were not retained, we could not examine foodstuffs for virus
isolation.
In Case 1, 150 persons were served with the same fullcourse dishes composed of hors d’oeuvres, raw and cooked
fish, tempura, vegetables dressed with various sauces (aemono),steamed eggs and the like at one restaurant on December 17,*Corresponding author: Mailing address: Department of Biology,Kanagawa Prefectural Institute of Public Health, Shimomachiya
1-3-1, Chigasaki-shi, Kanagawa 253-0087, Japan. Tel: +81-46783-4400, Fax: +81-467-83-4457, E-mail: furuya.6nge@pref.
kanagawa.jp391

Table 1. Foodborne disease
Case

Date of onset

Place of preparing foodConsumers

123
4

Dec. 17
Dec. 17
Dec. 18
Dec. 20

restaurantrestaurant
hotel
restaurant

150
153
50
24Patients
Sampled Positive

no.
65
58
25
1732
34
412Kitchen staff
Sampled Positive

27
27
31134
81265153

Genogroup
GII
GI, GII, GIGIIGIIGII

Table 2. Gastroenteritis outbreaks
Case

Date of onset

Setting of outbreak

Classification

Patients

Samples

Positive

Genogroup30
875GII

5Dec. 21

welfare facility

residents
staff members

6Dec. 27

hospitalpatients
staff members

5386GII

7Dec. 28

welfare facility

residents
staff members

30164630GII

8Dec. 29

hospitalpatients
staff members

72133022GII

9Dec. 30welfare facility

residents
staff members

14364

GII

members had many chances to become infected. In suchcircumstances, a virus can easily spread and transmission canthen occur from residents to staff members. As we learned
from Case 9, staff members must be extremely careful not tobring NVs into welfare facilities. In practice, frequent andextensive hand washing with soap and water is effective. It
is also important that staff members wear masks and use
disposable gloves while cleaning areas substantially contaminated by stools or emesis (4).

2004. Sixty-five persons developed disease with diarrhea,
abdominal pain and vomiting. Thirty-two patient stool samples
were tested, and NVs were detected in 27 stools. It is notablethat NVs were detected in stool samples of 5 kitchen staffs.
The relationship of individual dishes and the illness wassurveyed for the causative specific food. Among served
subjects, aemono was considered to be associated with theillness (data not shown).
In Case 2, 58 persons out of 153 who ate the same dishes
at another restaurant on December 17 presented similar symptoms, such as diarrhea, abdominal pain and vomiting. In thiscase, persons had raw or uncooked oysters. NVs genogroup I(GI) and genogroup II (GII) were detected from stools ofpatients as well as kitchen staff. From 6 stools, only GIs weredetected. From 10 stools, only GIIs were detected. Both GI
and GII were detected in 12 stools.
It is of note that in all cases, NVs were detected from stoolsof patients as well as kitchen staff. In particular, in Cases 1, 3and 4, it is very likely that the cause was contamination offoodstuffs or cooking wares by infected kitchen staffs.
As shown in Table 2, Cases 5 to 9 were gastroenteritis outbreaks caused by NVs occurred in 3 welfare facilities and 2
hospitals. NVs of GII were detected in all of the cases. In allcases, residents in the welfare facilities, patients and staff
members had similar symptoms such as diarrhea, abdominal
pain and vomiting.
In Case 9, a staff member had vomiting and abdominal
pain on December 30. From January 2 to January 3, 2 otherstaff members and 7 residents had vomiting and diarrhea. In
10 days a total of 17 persons developed the disease. This caseindicated that a staff member was the index case and NV
subsequently spread to other staff members and residents.
At welfare facilities and hospitals, where staff members
come into contact with stools of residents and patients, staff

This article appeared in the Infectious Agents Surveillance
Report, vol. 26 no. 3, p. 71-72, 2005 in Japanese.
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