Interview with Infectious Diseases Specialist, Dr. Sonam Topgyal, Seattle, Washington. Dr. Topgyal said that prevention and education is most important to understand and for treatment of Aids, and that the most common infectious disease among Tibetans is Tuberculosis, followed by Hepatitis B. Talking of prevention of Aids, Dr. Topgyal highly recommends everyone age 13 and above to get tested for HIV.