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

Laboratory and Epidemiology Communications

An Outbreak of Acute Gastroenteritis Caused by Human Group C
Rotavirus in a Welfare Institution in Okayama Prefecture
Mitsutaka Kuzuya*, Masako Hamano, Michiko Nishijima, Ritsushi Fujii, Hajime Ogura,Misao Tanaka1, Akio Oda1, Sachie Kusaka1 and Mitsuko Naitou1
Department of Virology, Okayama Prefectural Institute for Environmental Scienceand Public Health, Okayama 701-0298 and1
Okayama Prefectural Tsuyama Public Health Center, Tsuyama 708-0051, Japan
Communicated by Tatsuo Miyamura(Accepted July 5, 2005)
Rotaviruses are members of the Reoviridae family and arerecognized as important causative agents of acute gastroenteritis. The genomes of rotaviruses consist of 11 segmentsof double-stranded RNA (dsRNA) enclosed in double-shelled
particles. Rotaviruses are classified into at least seven groups(groups A-G) on the basis of their dsRNA electropherotypes
and a common group antigen on the inner capsid protein (1,2). Three of these groups (A, B and C) are known to infecthumans (1,2). Several outbreaks of acute gastroenteritis causedby human group C rotavirus (CHRV) have been reported inJapan (3-9). Most of these outbreaks occurred in school-aged
people aged 6 to 18 years. Generally, an outbreak of CHRV*Corresponding author: Mailing address: Department of Virology, Okayama Prefectural Institute for Environmental Scienceand Public Health, 739-1 Uchio, Okayama 701-0298, Japan. Tel:+81-86-298-2681, Fax: +81-86-298-2088, E-mail: mitsutaka_kuzuya@pref.okayama.lg.jp
255

Jpn. J. Infect. Dis., 58, 2005
gastroenteritis in adults is rather rare (10). Here we reportan outbreak of CHRV infection in adults that occurred in awelfare institution.
On 25 December 2004, we received a report of an outbreak of gastroenteritis in a welfare institution located in
the northern area of Okayama Prefecture. The outbreak wasinvestigated immediately. Among 233 adults in the institution (149 residents and 84 employees), 24 people (16 residentsand 8 employees) aged 34 to 67 years showed symptoms ofgastroenteritis. The index case (a resident) developed thedisease on December 22, and the outbreak then peaked onDecember 25 with 8 residents and 3 employees showing
symptoms. Thereafter, small numbers of new patients continued to appear until December 31.
Fecal specimens were obtained from two patients on day 2
after the initial appearance of symptoms and were used forelectron microscopic (EM) analysis and the detection of thenorovirus genome by reverse transcriptase-polymerase chain
reaction (RT-PCR) (11). Rotavirus-like particles were detectedby EM in the specimen from case 2, but norovirus genome
was not detected in either specimen (Table 1). Therefore, thespecimens were further examined for the presence of group
A rotavirus and CHRV by RT-PCR (9,12). As shown in Table
1, CHRV was detected in both patients but group A rotavirus
was not detectable, indicating that this outbreak was causedby CHRV. The route of the CHRV infection remains unknown
because the number of fecal specimens from the patients waslimited.
For further epidemiological analysis, the major outer capsid
glycoprotein (VP7) genes of CHRV amplified by RT-PCR
were directly sequenced. The nucleotide sequence data wereanalyzed by the GENETYX-MAC version 10 program(Genetyx, Tokyo, Japan), and phylogenetic analysis wasperformed using the Clustal W program employing theneighbor-joining method with bootstrapping 1,000 times. A
comparison of the full-length VP7 genes of the CHRV isolates (AE52 and AE53) from the patients showed that bothsequences were identical, suggesting that the outbreak wascaused by a single CHRV strain. Phylogenetic analysis using
published sequences of CHRV strains isolated in Okayama
Prefecture showed that the isolate (AE53) was geneticallyclosely related to the KW408 and OT99 strains (retrieved in1998 and 1999, respectively) isolated from patients aged 4
and 11 years, respectively (Fig. 1). These results suggest thatthe present outbreak was caused by a CHRV strain circulating in Okayama Prefecture.
This article appeared in the Infectious Agents Surveillance
Report, vol. 26, p. 100-101, 2005 in Japanese.

Table 1. Clinical symptoms in patients with gastroenteritis and detection of viral agents in their fecal specimens
CaseNo.

Age(years)

Sex1
2

5353

FM

Onset ofdiseaseAPDec 27
Dec 27++Laboratory diagnosis for viral agents
RT-PCR detection forEMNorovirus ARV CHRVClinical symptoms
Diarrhea N/V Fever+++––––Rotavirus––––++

AP, abdominal pain; N/V, nausea or vomiting; EM, electron microscopy; ARV, group A rotavirus.

0.01

KW290 (1996)

90

KU166 (2000)
AE53 (2004)

84
98

OT99 (1999)
KW408 (1998)
99

G-7 (1992)
OK118 (1988)
K9304 (1993)
98

KC48 (1995)
98

OK459 (1989)
OK450 (1989)
100

I57 (1990)
Cowden (Outgroup)

Fig. 1. Phylogenetic analysis of the nucleotide sequences of the VP7 gene of 12 CHRV specimens isolated in Okayama
Prefecture (GeneBank accession numbers as follows: D87543, D87544, AB004250, AB086962-086969). The phylogenetic
tree was constructed based on the neighbor-joining method with porcine group C rotavirus, Cowden strain (accessionnumber, M61101) as an outgroup. The percentage of bootstrap values is shown at branch node. The scale bar represents a
1% nucleotide difference. The strains isolated from outbreak cases are indicated by boldface, and the isolate (AE53) fromthe present outbreak is underlined. The year in which each strain was isolated is indicated in parenthesis.

256

Jpn. J. Infect. Dis., 58, 2005
7. Sawada, H., Yoshizumi, S., Tamate, N., Arata, Y.,
Katsuyama, S., Furuya,T., Hotta,T. and Hiraki, M. (1998):
Outbreak of gastroenteritis due to group C rotavirus in a
primary school. Infect. Agents Surveillance Rep., 19,252-253 (in Japanese).
8. Hamano, M., Kuzuya, M., Fujii, R., Ogura, H., Mori, T.,Nakayama, T., Yuen, E., Katayama, K., Mitsunobu, Y.
and Inoue, K. (1999): Outbreak of acute gastroenteritis
caused by human group C rotavirus in a primary school.
Jpn. J. Infect. Dis., 52, 170-171.
9. Kuzuya, M., Fujii, R., Hamano, M. and Ogura, H. (2003):
Outbreak of acute gastroenteritis caused by human group
C rotavirus in a youth educational center in Okayama
Prefecture. J. Jpn. Assoc. Infect. Dis., 77, 53-59 (in Japanese).
10. Oishi, I., Yamazaki, K. and Minekawa, Y. (1993): An
occurrence of diarrheal cases associated with group C
rotavirus in adults. Microbiol. Immunol., 37, 505-509.
11. Kageyama, T., Kojima, S., Shinohara, M., Uchida, K.,Fukushi, S., Hoshino, F. B., Takeda, N. and Katayama,
K. (2003): Broadly reactive and highly sensitive assay
for Norwalk-like viruses based on real-time quantitative
reverse transcription-PCR. J. Clin. Microbiol., 41, 15481557.
12. Gouvea, V., Glass, R. I., Woods, P., Taniguchi, K., Clark,
H. F., Forrester, B. and Fang, Z. Y. (1990): Polymerase
chain reaction amplification and typing of rotavirus
nucleic acid from stool specimens. J. Clin. Microbiol.,28, 276-282.

REFERENCES
1. Bass, D. M. and Greenberg, H. B. (1995): Group A
rotaviruses, p. 967-982. In M. J. Blaser, P. D. Smith, J.
I. Ravdin, H. B. Greenberg and R. L. Guerrant (ed.),Infections of the Gastrointestinal Tract. Raven Press, Ltd.,New York.
2. Saif, L. J. (1990): Nongroup A rotaviruses, p.73-95. In
L. J. Saif and K. W. Theil (ed.), Viral Diarrhea of Manand Animals. CRC Press, Boca Raton, Florida.
3. Matsumoto, K., Hatano, M., Kobayashi, K., Hasegawa,A., Yamazaki, S., Nakata, S., Chiba, S. and Kimura, Y.
(1989): An outbreak of gastroenteritis associated withacute rotaviral infection in schoolchildren. J. Infect. Dis.,
160, 611-615.
4. Sekine, S., Hayashi, Y., Andoh, T. and Ohta, K. (1992):
An outbreak of gastroenteritis due to group C rotavirusin Tokyo. Infect. Agents Surveillance Rep., 13, 150 (inJapanese).
5. Shinozaki, K., Yamanaka, T., Ogawa, T., Tokieda, M.,
Takahashi, T., Ohta, Y., Sakai, T. and Tsunekane, M.
(1996): Outbreak of gastroenteritis by human group Crotavirus. Infect. Agents Surveillance Rep., 17, 299 (inJapanese).
6. Hasegawa, S., Matsuura, K., Nakayama, T., Ishikura, M.,
Kitamura, T., Yasui, Y. and Kaneko, M. (1997): An outbreak of group C rotavirus gastroenteritis in a primaryschool. Infect. Agents Surveillance Rep., 18, 302-304(in Japanese).

257