[1] Nagasaki Univ, Dept Internal Med, Nagasaki 852, Japan
[2] Nagasaki Univ, Dept Social Environm Med, Nagasaki 852, Japan
[3] Nagasaki Univ, Res Ctr Trop Infect Dis, Inst Trop Med, Nagasaki 852, Japan
[4] Univ Peradeniya, Dept Microbiol, Peradeniya, Sri Lanka
[5] Kurume Univ, Sch Med, Div Infect Dis, Dept Infect Med, Kurume, Fukuoka 830, Japan