1. Department of Microbiology and Immunology, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, PC 123, Oman.
2. Department of Medicine, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, PC 123, Oman.
3. Department of Genitourinary, Al Nahdha Hospital, Muscat, PC 123, Oman.
4. Department of Internal Medicine, Al Nahdha Hospital, Muscat, PC 123, Oman.
5. Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California 94305.