Jpn. J. Infect. Dis., 53, 216-217, 2000

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Laboratory and Epidemiology Communications

The First Reported Case of Japanese Spotted Fever in Hiroshima Prefecture, Japan

Shinichi Takao*, Yoshiro Kawada1, Motohiko Ogawa2, Shinji Fukuda, Yukie Shimazu, Masahiro Noda and Shizuyo Tokumoto

Division of Microbiology II, Hiroshima Prefectural Institute of Health and Environment, Minami-machi 1-6-29, Minami-ku, Hiroshima 734-0007, 1Department of Dermatology, Onomichi Municipal Hospital, Shin-takayama 2-1170-177, Onomichi 722-8503 and 2Department of Virology II, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku-ku, Tokyo 162-8640

Communicated by Hiroo Inouye

(Accepted November 21, 2000)

The spotted fever group rickettsioses, which are transmitted by ticks, have a worldwide distribution. Japanese spotted fever (JSF), one of the newcomers to this group, was first reported in Tokushima Prefecture, Japan in 1984 (1-2). The causative agent of JSF was isolated in 1986 (3) and named Rickettsia japonica (4).

Following that, surveillance for JSF was started by the Working Group for Tsutsugamushi Disease Surveillance, which is composed of municipal public health institutes and the National Institute of Infectious Diseases in Japan. According to the surveillance information provided by this group, a total of over 200 JSF cases have been reported from 10 different prefectures between 1984 and 1998, with the JSF-endemic prefectures all located on the Pacific coast except for Shimane and Hyogo Prefectures (5). On the other hand, there have been no reports of JSF from the prefectures located along the Seto Inland Sea coast except for Hyogo and Wakayama Prefectures (Figure). In this paper, we report the first case of JSF in Hiroshima Prefecture determined by serological diagnosis.

An 82-year-old man from Onomichi City, Hiroshima Prefecture, visited a local clinic on October 8, 1998, complaining of a fever (37.8), head ache, general fatigue and rash. Faropeneum sodium, fosfomycine, and isepamycine sulfate were administered for several days without effect, and he was admitted to the Onomichi Municipal Hospital, where he was treated with minocycline hydrochloride for 4 weeks until he recovered. His clinical symptoms on admission were high fever (40.0), erythematous eruption, eschar on the right side of his back, regional lymphadenopathy, and hepatosplenomegaly. A few days before the onset of illness, he had been engaged in forestry activities and farming near his house. At first sight, the epidemiological states and clinical symptoms were like those of tsutsugamushi disease (scrub typhus). However, serodiagnoses of the acute- and convalescent-phase sera by means of indirect immunofluorescence assay using Orientia tsutsugamusi antigen (Kato, Karp, and Gilliam strains) and R. japonica antigen (YH strain) revealed it to be JSF infection. As shown in Table, while no specific antibodies to O. tsutsugamusi or R. japonica were found in the acute-phase serum, R. japonica-specific IgG (1:40) and IgM (1:160) antibody were found in the serum collected on the 35th day after the onset of illness. The patient's IgG antibody titer further increased to 1:160 at 6 months (187 days) after the onset of illness. No increase of anti-O. tsutsugamusi antibody was seen.

JSF is not commonly recognized by clinicians, because outbreaks of JSF have been sporadic and limited. However, since the endemic area of JSF appears to be expanding, as shown in this report, we propose a careful monitoring of JSF as an emerging infectious disease even in the area non-endemic for JSF.


  1. Mahara, F.(1984):Three Weil-Felix reaction (OX2) positive cases with skin eruptions and high fever. J. Anan Med. Assoc., 68, 4-7 (in Japanese).
  2. Mahara, F., Koga, K., Sawada, S., Taniguchi, T., Shigemi, F., Suto, T., Tsuboi, Y., Oya, A., Koyama, H., Uchiyama, T. and Uchida, T.(1985): The first report of the rickettsial infections of spotted fever group in Japan; three clinical cases. J. Jpn. Assoc. Infect. Dis., 59, 1165-1172 (in Japanese).
  3. Uchida, T.(1993): Rickettsia japonica, the etiologic agent of oriental spotted fever. Microbiol. Immunol., 37, 91-102.
  4. Uchida, T., Uchiyama, T., Kumano, K. and Walker, D.H.(1992): Rickettsia japonica sp. nov., the etiological agent of spotted fever group rickettsiosis in Japan. Int. J. Syst. Bacteriol., 42, 303-305.
  5. National Institute of Infectious Diseases and Infectious Disease Control Division, Ministry of Health and Welfare (1999): Japanese spotted fever. Infect. Agents Surveillance Rep., 20, 211'-212'.

*Corresponding author: Fax: +81-82-252-8642, E-mail:

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