As used in this article, unless the context requires a different meaning: “Appropriate precautions” means those specific measures which have been demonstrated by current scientific evidence to assist in preventing transmission of a communicable disease of public health significance. Appropriate precautions will vary according to the disease. “At-risk behavior” means engaging in acts which a person, who has been informed that he is infected with a communicable disease of public health significance, knows may infect other persons without taking appropriate precautions to protect the health of the other persons. “Communicable disease of public health significance” means an illness of public health significance, as determined by the State Health Commissioner, caused by a specific or suspected infectious agent that may be transmitted directly or indirectly from one individual to another. “Communicable disease of public health significance” shall include, but may not be limited to, infections caused by human immunodeficiency viruses, blood-borne pathogens, and tubercle bacillus. The State Health Commissioner may determine that diseases caused by other pathogens constitute communicable diseases of public health significance. Further, “a communicable disease of public health significance” shall become a “communicable disease of public health threat” upon the finding of the State Health Commissioner of exceptional circumstances pursuant to Article 3.02 (§ 32.1-48.05 et seq.) of this chapter.