617. An “Asian variant” rather than the strains endemic to the main island of Japan: Clinical features of Scrub typhus at Ikema island in Okinawa, Japan
Session: Poster Abstract Session: Oh One World: Infections from Near and Far
Thursday, October 27, 2016
Room: Poster Hall
  • Tsutsugamushi SS 10-18−7.pdf (505.4 kB)
  • Background:

    The details of epidemiology, clinical features and phylogenetic information of scrub typhus (ST) in Okinawa, where belongs to Ryukyu Islands in Japan have not been described until this presentation. Of note, the field research at Ikema island from 2009 to 2010 revealed a number of Leptotrombidium deliense, known as a vector of ST in Southeast Asia.


    We reviewed the charts of patients diagnosed with ST from 2008 to 2015 at Okinawa Miyako Hospital, a core clinical hospital in Miyako island, Okinawa, Japan


    The total 11 cases of ST are diagnosed by elevated serology as well as real time PCR of eschar and blood from 2008 to 2015. Average age of patients showed 59.6 years old (range of 38 to 84), 7 of men and 4 of women, 18% (2/11) of aseptic meningitis, 18% (2/11) of DIC with shock state were found, however, no case was died of ST. Bimodal seasonal distribution of onset was described in “summer” from April to July (7 cases) and in “autumn to winter” from October to December (4 cases). The eight patients are residents in Ikema Island, and the other 3 patients had stayed at Ikema Island before the onset of scrub typhus. Detailed history taking revealed the estimated exposed places, which are localized to the two places in Ikema island: northwest and the south of the island. These estimated exposed places are located close to the seven areas in Ikema Island where confirmed the chigger of Leptotrombidium deliense by field research from 2009 to 2010. The ten out of 11 cases were diagnosed as ST by real-time PCR analysis of eschars and blood in the year of 2008 to 2015. Phylogenetic information by the gene sequences of the locus for the 56-kDa proteins revealed the 3 strains; 6 of Gilliam-variant, 3 of Saitama-variant and one of Karp-variant, which are also reported in Taiwan. A patient had recurrent infection 12 months later by different strains, Saitama-variant and Gilliam-variant respectively.


    The clinical features and the gene sequences of ST at Ikema island in Okinawa are unique compared with the strains endemic to the main island of Japan. The single vector of Leptotrombidium deliense in Ikema island can do carry plural strains of Orientia Tsutsugamushi, which was demonstrated as recurrence of different strains in the same patient.

    Shuichi Sugita, M.D.1, Sho Okano, Ph.D2, Jun Kudaka, Ph.D2, Katsuya Taira, Ph.D3, Masashi Narita, M.D.4, Masafumi Funato, M.D.1, Haruka Eda, M.D.1, Young Lee, M.D.1, Hiroyuki Tsuyuki, M.D.1, Yusuke Yamanaka, M.D.1, Akira Shimabukuro, M.D.1, Eiji Motonaga, M.D.1 and Okinawa Miyako Hospital , (1)Okinawa Miyako Hospital, Miyakojima city Okinawa, Japan, (2)Okinawa Prefectural Institute of Health and Environment, Nanjo city、Okinawa, Japan, (3)Department of Public Health and Medical Care, Okinawa Prefectural Government, Naha city Okinawa, Japan, (4)Department of Medicine, Okinawa Chubu Hospital, Uruma, Okinawa, Japan


    S. Sugita, None

    S. Okano, None

    J. Kudaka, None

    K. Taira, None

    M. Narita, None

    M. Funato, None

    H. Eda, None

    Y. Lee, None

    H. Tsuyuki, None

    Y. Yamanaka, None

    A. Shimabukuro, None

    E. Motonaga, None

    Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.