A virus is a minute particle that behaves like a parasite in living things including plants, animals, humans, and bacteria. A virus is constructed much like a bomb: it has a soft core (explosive) and a hard outer shell (protection). In the case of a virus, the outer shell is protein-based which allows it to easily mimic—and in some cases assimilate—host cells. As the protein shell combines with that of the host cell, the soft core consisting of nucleic acids is able to manipulate the cell's organelles, forcing them to abandon their original purpose and become reproducers of the virus.
Though incredibly hardy and adaptive, viruses cannot live independently; they rely on host cells to survive and to replicate. Without a host cell, most viruses have incredibly short half-lives.
An open wound presents a barrier free path to your circulatory, lymphatic, and respiratory systems. Because every body modification results in an open wound at some point during the active modification process or healing process, viruses are of great concern.
Though influenza may not sound like a life-threatening virus, some strains are fatal. Influenza is highly contagious, can cause temporary mental distortion resulting in headaches and seizures (resulting primarily from sinus congestion), affects balance and concentration, and weakens the immune system a great deal, thereby posing a variety of problems for modification application and healing. Influenza is transmitted by fluid droplets, usually distributed by secretions resulting from a sneeze or cough (oral piercings, nostril piercings, and septum piercings can trigger sneezing and/or coughing).
Both HIV and Hepatitis are viruses transmitted through blood-to-blood contact. The most likely time for a blood-to-blood transfer to occur resulting in infection would involve a needle stick injury. Though modification procedures often involve blood, it is unlikely that you will contract HIV during a body modification procedure because of the nature of the virus. The real risk during body modification procedures is Hepatitis. Though there are five types of Hepatitis, the Hepatitis C Virus is the most prevalent, it should be noted that most people have no symptoms of Hepatitis C, and the only real way to know if you carry the virus is to be tested. Everyone involved in body modification is encouraged to get tested for HIV and the Hepatitis viruses yearly as a precautionary measure.
Regardless of the virus, each poses a threat to the health and well-being of both practitioners and participants in body modification. If you have the flu, are HIV positive, have any of the Hepatitis viruses, or have recently been at risk for any of the above, have the courtesy to tell your body modification practitioner so they can take extra precautions if necessary. Be aware these extra precautions may include refusal to practice on you. This is not only for their safety, but for yours as well. A practitioner who is uncomfortable with their client may not be on top of their game, and that alone will pose a greater risk to you both than even the virus could.