In epidemiology, contact tracing is the identification and diagnosis of persons who may have come into contact with an infected person. For sexually transmitted diseases, this is generally limited to sexual partners and can fall under the heading of partner services, but for highly virulent diseases such as Ebola and tuberculosis, a thorough contact tracing would require information regarding casual contacts.
By tracing the sexual partners of infected individuals, testing them for infection, treating the infected and tracing their contacts in turn, STI clinics could be very effective at suppressing infections in the general population.
In the 1980s, first genital herpes and then AIDS emerged into the public consciousness as sexually transmitted diseases that could not be cured by modern medicine. AIDS in particular has a long asymptomatic period—during which time HIV (the human immunodeficiency virus, which causes AIDS) can replicate and the disease can be transmitted to others—followed by a symptomatic period, which leads rapidly to death unless treated. HIV/AIDS entered the United States in about 1969 likely through a single infected immigrant from Haiti. Recognition that AIDS threatened a global pandemic led to public information campaigns and the development of treatments that allow AIDS to be managed by suppressing the replication of HIV for as long as possible. Contact tracing continues to be an important measure, even when diseases are incurable, as it helps to contain infection.