Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, R.O.C.

^*Correspondence to: Dr Feng-Yee Chang, Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, 325, Section 2, Cheng-Kung Road, Neihu, Taipei 114, Taiwan, R.O.C.

E-mail: [email protected]

Received: February 5, 2007; • Accepted: March 12, 2007.