The term “latency period” can refer to two different things in the medical world. In the first sense, a latency period is a period in which someone is infected with a disease, but no symptoms are observable. This stage is also known as the incubation period, reflecting the idea that the disease is incubating in the body. Psychoanalysts also use the term “latency period” if they subscribe to the Freudian approach, using the term to refer to a specific stage in child development.
In the first sense, the latency period of disease is a topic of great interest among epidemiologists and medical researchers. When someone is infected with a disease, he or she can pass the disease on, even if no symptoms are present, and the latency period often represents a window of opportunity for a disease to spread itself far and wide without the awareness of the host. Latency periods tend to be longer in adults than in children or people with compromised immune system, reflecting the body's fight against the invader, which slows the appearance of symptoms.
Latency periods can be of varying length. Some infections present themselves within a few hours or days. For example, people who consume disease-causing toxins often experience a very short latency period between the ingestion of the toxin and the appearance of symptoms. In other cases, a disease may be dormant for months of years, manifesting many years after it was contracted. Creutzfeldt-Jakob Disease (CJD) is an example of a disease with a very long latent period, of up to 30 years in some cases.
During the incubation period, hosts can unwittingly spread an infection because they are not aware that they are carrying one. In diseases with an extended latency period, this can mean that the hosts infects numerous other people who are not able to trace their contact with the host to determine where they got the disease. This was a common problem with HIV in the 1980s, when infected individuals transmitted the disease to casual sexual contacts and recipients of blood products without even knowing that they were sick.
In the Freudian sense, the latency period comes between the ages of five or six and early adolescence. It is the fourth of five stages of development, characterized by the emergence of sexual urges which are sublimated or repressed. According to psychoanalytic theory, people in their latency phase tend to seek the company of people of the same gender, and they may develop a number of emotions about sexual activity in response to their own subconscious and cultural and social cues.