Epidemiologic features of human prion diseases in Japan: a prospective 14-year surveillance

Ae, Ryusuke

Epidemiologic features of human prion diseases in Japan: a prospective 14-year surveillance

Monday, 18 August 2014

Exhibit hall (Dena'ina Center)

Ryusuke Ae, MD , Jichi Medical University, Shimotsuke, Japan

Takao Kojo, PhD , Jichi Medical University, Shimotsuke, Japan

Satoshi Tsuboi, PhD , Jichi Medical University, Shimotsuke, Japan

Yasuko Aoyama, PhD , Jichi Medical University, Shimotsuke, Japan

Kazuhiko Kotani, PhD , Jichi Medical University, Shimotsuke, Japan

Hisako Takamura, PhD , Jichi Medical University, Shimotsuke, Japan

Enku-Oyun Tsogzolbaatar, MPH , Jichi Medical University, Shimotsuke, Japan

Masahito Yamada, PhD , Kanazawa University Graduate School of Medical Science, Kanazawa, Japan

Hidehiro Mizusawa, PhD , Tokyo Medical and Dental University Graduate School of Medical and Dental Sciences, Tokyo, Japan

Yosikazu Nakamura, MPH , Jichi Medical University, Shimotsuke, Japan

INTRODUCTION: The nationwide prospective surveillance for human prion diseases in Japan has been conducted since 1999. This study aimed to reveal epidemiologic features of human prion diseases in Japan by using the surveillance data.

METHODS: Information about patients suspected to have human prion diseases was obtained from 3 sources: (1) registries to the Intractable Disease Treatment Research Program, (2) notifications based on the Infectious Diseases Control Law, and (3) requests for genetic or CSF analysis by physicians to the members of the Creutzfeldt-Jakob disease (CJD) Surveillance Committee. We analyzed the data obtained from all the patients suspected of human prion diseases who were registered by the CJD Surveillance Committee between April 1999 and October 2013. All the referrals were assessed according to the World Health Organization case definition.

RESULTS: During the surveillance period, 4281 suspected patients were identified, and 2162 patients were confirmed as having prion diseases: definite (n=245, 11%) and probable (n=1668, 77%) cases. Diseases included sporadic CJD (n=1655, 77%), genetic CJD (n=415, 19%, including familial CJD [n=325, 15%], Gerstmann-Sträussler-Scheinker syndrome [GSS, n=85, 4%], and fatal familial insomnia [n=3]), dura mater graft-associated CJD (dCJD, n=84, 4%), variant CJD (n=1), and unclassified CJD (n=7). The age-specific incidence rates of human prion diseases in 2011 (per 1 million populations) were higher with age (40-49 years: 0.3, 50-59 years: 1.7, 60-69 years: 2.8, and 70-79 years: 6.3). During 1999-2011, annual incidence rates increased only in older groups. A total of 1622 deaths were reported; the mean duration from disease onset to death was 18 months, ranging from 16 months in sporadic CJD to 61 months in GSS.

CONCLUSIONS: In Japan, the proportions of dCJD and genetic CJD were relatively higher than other countries. Particularly, the number of dCJD was markedly higher.