Author affiliations: Kyushu University, Fukuoka, Japan (K. Goto, M. Sanefuji, K. Kusuhara, R. Kira, H. Torisu, T. Hara); National Institute of Infectious Diseases, Tokyo, Japan (Y. Nishimura, H. Shimizu); 1Current affiliation: University of Occupational and Environmental Health School of Medicine, Kitakyushu, Japan.
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