Figure 7: HIV/AIDS data from CDC, in the USA from 1981-1996 [95]. Note the considerable lag between the AIDS diagnoses and the estimated prevalence of HIV infection when HIV/AIDS was first diagnosed in the USA. Mean survival time from HIV infection is 12 years after infection without treatment, demonstrating that emerging infections with prolonged incubation periods or periods before clinical signs develop may be well established before diagnoses are made, even in developed countries.