Disease the time between infection and the appearance of symptoms. The latency period is the time between infection and the ability of the disease to spread to another person, which may precede, follow, or be simultaneous with the appearance of symptoms. Some viruses also exhibit a dormant phase, called viral latency, in which the virus hides in the body in an inactive state. For example, varicella zoster virus causes chickenpox in the acute phase; after recovery from chickenpox, the virus may remain dormant in nerve cells for many years, and later cause herpes zoster (shingles). Diseases may be classified by cause,
Technical diving magazine was using the term "technical diving", as an analogy with the established term "technical (rock) climbing". In the US the Occupational Safety and Health Administration categorises diving which is not occupational as "recreational diving" for purposes of exemption from regulation. This is also the case in some other countries, including South Africa. There is some professional disagreement as to what exactly technical diving encompasses. Nitrox diving and rebreather diving were originally considered technical, but this is no longer universally the case as several certification agencies now offer Recreational Nitrox and recreational rebreather training and certification. Some training agencies classify