Jpn. J. Infect. Dis., 53, 2000

Laboratory atld Epideniology Connunications

Adenovirus Type 7 Outbreaks in Japan in 1998
Shizuko Yamadera*, Kazuyo Yamashita, Masae Akatsuka, Nobuko Kato,
Mariko Tokunagaand Sakae Inouye
lnfectious Disease Surveillance Center, National Institute ofInfectious Diseases,
7Toyama I‑2311, Shinjuku‑ku, Too)oCommunicated by Hiroshi Yoshikura(Accepted March 22, 2000)

higher thanthat of sporadic casesin1998･

Japanexperienced a large adenoviruS 7 epidemicin1950(I). Signs of its resurgence have been noted since 1995 (2).

We report here theanalysis of adenoviruS 7 epidemics inTable I. Adenovirus isolates in 1998

Japanfrom1997‑1998.
In 1998, adenoviruS 3 Occupied 50% of the total adenovirus
isolated that year. AdenoviruS 7 was thethird most frequent

Adenovirus type% total

12345678日̲ 9M

adenoviruSinfection observed. It occupied 1 l% of the total

115

10 ′b O 1 5 1 1 0 0 3 2isolates (Table I). Serious complications of adenoviruS 7infection, such as meningitiSand encephalitis, were observed.
The major Clinical signs wereinflammation of upper resplra‑
tory tract, gastroenteritis, keratoconJunCtivitis,andinflamma‑tion of lower respiratory tract (Table 2). Keratoconjunctivitis

was more commoninoutbreak cases. However, the general

5 4symptoms were reportedly less severeinoutbreak cases.
There were 40 outbreaksin1997and 27in1998. Outbreaks
were mostfrequentinsummer seasonsand relatively rarein
Winter. In 1997, Outbreaks occurred mainly in June‑August,4‑

but there was a smallpeak of outbreaks from December toFebruary, 1998. In 1998, the outbreak was clusteredinApri1‑

Table 2. Clinical symptoms of adenoviruS 7 infection (1998)

June,and none were reported in August. A small peak ofoutbreaks were seeninSeptember‑November of that year

Innammation of upper resplratOry tract3111

1仰7 9 4 3 3 2 つ▲ 0 1

Gastroenteritis(Fig.).

KeratoconJ unCtivitis

Instances of adenoviruS 7 were most commonly detectedby family members (63%in1997and 67% in 1998). h regard

Inflammation of lower resplratOry tract

to site of outbre水, nursery schoolsand kindergartens consti‑Men ingltlStuted 30%in1997 (each 15 %), whilein1998 primary schoolsJoint and muscular paln

constituted 26 % (Table 3). Thoughthe average age of theEnlargement of lymph nodes

patientsinthe outbreaksand thatinthe sporadic cases wereEncephal itis

similarin1 997,the average age of outbreak cases was slightly

3Others654321 0 0 0 0 0 08tLOTt■一OB!L9TtJTAOtLaP 10 Ja一Tt Nq‑LrOTJS一t,31qlrLO IO haqtnNO0

2 1 0Figure･ Isolations and outbreaks ofadenoviruS 7 in 1997‑1998･The line graph showsthe number of adenoviruS 7 isolations per month, whilethe bar graphshowsthe number of outbreaksper month.
*Co汀eSpOnding author: Fax: +8 1 ‑42‑393‑6708

22

Jpn. J. Infect. Dis., 53, 2000
Table 3. Places of detection of patients
1997
Family63

Primary

Sch001

Nursery

SchooI

K

indergarten

Hosp

ita1

(%)

5151

the progr年m Ofthe National Epidemiological Surveillance ofInfectiousDiseases. Wethank alsothose who gave us valuable

1998
67

advices and suggestions.

(%)

26

REFERENCES

75301. Nishio, 0., Matsui, K., Akiyama, M., Matsunaga, Y and0Inouye, S. (1998): Change in antibody prevalence toadenoviruStype 7 duringthe past 20 yearSinJapan･ Clin･
Viro1., 26, 255.
Schools, hospitals, and other institutional sites appear to

2. Yamadera, S., Yamashita, K., Akatsuka, M., Kato, N.and

playanimportant roleinthe spread ofadenoviruS 7. In 1997,
the adenoviruS 7infection which startedina nursery school
spread to familiesandthen tothe primary schools (3). h 1998,
the adenoviruS 7infection spread to familiesinspite of closureof the classes in the primary school affected (4). Hospital
infection was also noticed (personal communication), whileInouye, S. (1998): Trend of adenovirus type7infection,anemerglng disease. Jpn. J. Med. Sci. Biol･, 51, 41‑49･
3. Imai, K., Terasoma, F.and Ishigaki, S. (1998): Spread ofadenoviruStype 7infectionamong nursery‑sch001 children
and their family members. Infect. Agents Surveillance
Rep., 19, 6 (inJapanese).
4. Yokota, Y., Oouchi, Y., Yoshida, T.and Omoto, Y. (1998):

some patients withcongenitaldiseases were reported to havedied (5). Recently, a large outbreak occurred in a training

Isolation of adenoviruStype 7from patients in ancenterinthe U.S.A., with 60% of the people infected withadenovirus 1 1 (6)･AsadenoviruS 7 sometime causes.Symptoms

outbreak of respiratory ilhessina prmary schoolinApri11 998. Infect. Agents Surveillance Rep., 19, 1 0 (inJapanese)･

more serious than influenza, adequate measures ln nursery

5･ Yokozaya, M･and Endo, R･ (1998): Severe cases ofschools, prlmary schools, and hospitals are needed foradenovlruS 7 infection: Clinical studies. Abstr. 39th

preventingthe spread of theinfection.

Assembly of Clinical Virology, Sapporo (inJapanese)･
6. Centers f♭r Disease Control and Prevention (1998):

We thank the prefectural and municipal public health

Civilianoutbreak of adenovirus respiratory disease‑Southinstitutesand the national hospitals which collaborated withDakota, 1997. Morbid. Mortal.Wkly. Rep., 47, 567‑570･23