Chlamydia is an extremely common sexually transmitted infection (STI) caused by the bacterium Chlamydia trachomatis. It is considered the most frequently reported bacterial infectious disease, with millions of new infections occurring globally each year. The infection is often called “silent” because most individuals, particularly women, experience no symptoms. This lack of noticeable signs is a major factor in its sustained spread, making tracing the source a frequent concern after diagnosis.
The Biological Reality of Source Tracing
Determining the specific individual who transmitted a chlamydia infection is generally not possible using current medical or biological methods. The primary difficulty is that the infection cannot be precisely dated. The incubation period, the time between exposure and when symptoms might appear, is typically estimated to be between seven and 21 days, but this range is variable.
This wide range means the infection could have been acquired weeks or even months before diagnosis. The bacteria can persist in the body for an extended period without causing symptoms. Since many infections are asymptomatic (70% in women and 50% in men), the person who passed on the infection may not have known they were infected.
Furthermore, Chlamydia trachomatis does not possess a unique biological signature linking it back to a single individual. While genetic analysis of the bacteria is possible, the widespread nature of circulating strains means a match points only to a general population. A positive test confirms the presence of the bacteria in the patient, not the identity of the source.
What Medical Testing Reveals (and Doesn’t Reveal)
The standard method for diagnosing chlamydia is the Nucleic Acid Amplification Test (NAAT), which is highly sensitive and detects the genetic material of the Chlamydia trachomatis bacterium. This test confirms an active infection is present by amplifying the pathogen’s nucleic acid from a collected sample, such as urine or a swab. NAATs are the preferred diagnostic tool due to their accuracy and non-invasive nature.
A positive NAAT result reliably indicates the patient currently has a chlamydia infection, but it cannot determine exactly when the infection was contracted. The test identifies the presence of the bacteria but cannot function as a microbial clock to date the exposure event. Testing too early after an encounter can yield a false negative result because the bacteria must multiply within the host cells before detection.
Public Health Responsibility: Partner Notification
Since medical testing cannot identify the specific source of the infection, the focus shifts to public health action aimed at preventing further transmission and protecting partners. Partner notification is the process of informing all recent sexual partners so they can be tested and treated. This action is necessary to break the chain of transmission and prevent re-infection.
Current guidelines advise the patient to notify all sexual partners from the 60 days preceding the diagnosis or symptom onset. If the last sexual contact was more than 60 days prior, the most recent partner should be notified. Patients can choose self-reporting or receive assistance from a healthcare provider or public health specialist.
Expedited Partner Therapy (EPT) is available in many jurisdictions. This harm-reduction strategy provides the patient with medication or a prescription for their partner without the partner first needing a clinical examination. The goal is not to assign blame, but to ensure partners receive timely treatment. This prevents serious complications of untreated chlamydia and minimizes the risk of patient reinfection.