Fortunately, chlamydia is a largely preventable infection. Learning how Chlamydia trachomatis behaves can give you a better understanding of what makes an infection more likely.
Chlamydia Bacterium
Most bacteria are capable of reproducing on their own as long as they’re in a hospitable environment—but not the type associated with chlamydia. The chlamydia bacterium must rely on its hosts (humans) to survive, much like a virus does.
Essentially, chlamydia treats the insides of human cells like great big grocery stores. From the host, it takes ATP (an energy molecule), nutrients, and other elements that are essential for reproduction and that the bacterium can’t make on its own.
Infection
Chlamydia basically has a two-phase life cycle: the elementary body and reticulate body stages.
Elementary Body
Chlamydia travels between cells, and between people, in the form of an elementary body—a small, dense, spore-like structure.
In this stage, chlamydia doesn’t do much of anything. Bacteria travel between cells and between people to create new infections, but these bodies don’t replicate or change. They are just carried around in bodily fluids.
Chlamydia is infectious, but not active in this stage.
Reticulate Body
Chlamydia enters this stage once the elementary body infects a new cell. In this form, the bacterium use supplies from the host cell to make copies of itself inside the cell.
Reticulate bodies can grow, divide, and metabolize. Infections can persist in this manner for a while.
Once there are enough copies—too many to survive inside the cell—reticulate bodies can turn back into elementary bodies, burst the host cell open, and escape to infect new cells (either in the infected individual or a sexual partner). This starts the process all over again.
This is a pretty strange life cycle that doesn’t really follow the roadmap for either a bacterial or viral infection. That is one of the reasons that chlamydia is so interesting and important to study.
Transmission
Discussing the characteristics of chlamydia is important because its characteristics affect the way the bacterium is transmitted from person to person. The method of transmission, in turn, affects the risk factors that make it more likely a person will contract the infection.
Understanding the elementary body stage also helps clarify why sometimes chlamydia infections are present for months or even years before they are detected. This is especially important if you have a partner who, upon learning of your chlamydia diagnosis, wonders how you became infected despite being in a committed sexual relationship with them for a lengthy period of time.
Lifestyle Risk Factors
Certain lifestyle practices can increase your risk of chlamydia infection, including:
Unprotected sex: Engaging in either vaginal, receptive anal, or oral sex without a condom is the greatest risk factor for developing chlamydia. Since bacteria are spread by secretions, using a condom every time you have sex (unless you’re in a long-term monogamous relationship in which both partners have tested negative) is the best way to avoid an infection. Having multiple sex partners: The more sex partners a person has, the more likely it is that they will develop an STI, including chlamydia. Of course, it only takes one sex partner to transmit the infection, and practicing safe sex is important no matter your sexual practices. A partner who has an STI: Obviously, an untreated partner poses a risk. But there is also a risk of transmission if a partner has not yet finished a full seven-day course of antibiotics, or if they received a single-dose medication and seven days have not yet passed. Men who have sex with men (MSM): Men who have sex with men are more likely to develop genital, rectal, and/or oral chlamydia infection than heterosexual men. In a study, 11. 8% of MSM in an urban area of the United States were found to have extragenital chlamydia infections involving either the anus or the throat.
Health Risk Factors
People with certain existing health concerns are at greater risk for chlamydia infection than others.
Health risk factors include:
Having other STIs: Lifestyle practices that can predispose you to another STI can also raise your risk of chlamydia (and vice versa). Many STIs also cause inflammation of the sensitive mucosa of the vagina, cervix, or urethra. When this tissue is compromised due to one infection, it’s easier for another microorganism to enter the body and begin to grow. Being HIV positive: Up to 10% of men who are positive for human immunodeficiency virus (HIV) will also test positive for chlamydia. Having cervical ectopy: Cervical ectopy, a condition in which the cells of the endocervix (cervical canal) are instead found on the ectocervix (outside the cervical canal), increases the susceptibility of the tissue to chlamydial infection. This condition is most common in young women. An older study looking at women aged 15–24 found that those with cervical ectopy were almost twice as likely to test positive for chlamydia. As women age, the cervical tissue migrates and cervical ectopy usually goes away, putting them at lower risk for chlamydia.
Untreated mothers can also pass chlamydia to their babies during birth.
Reinfection
Unlike some infections, in which a person develops immunity after exposure, the body does not develop any immunity against chlamydia after an infection. This means that you can be infected over and over again.
Prevention
Reducing your risk of contracting chlamydia and practicing safe sex begins with choosing your sex partners wisely.
While asking a potential partner about previous diagnoses may not exactly be something you’d like to do, know that people are having these important conversations much more often now than in the past. Protecting your health is nothing to feel embarrassed about.
Reducing your risk with oral sex is also possible. Condoms can be used during fellatio, and dental dams or other barriers can be used during rimming or cunnilingus.
Even if you are careful, it’s still important to see your healthcare provider regularly and undergo routine screening for chlamydia. Only 5%–30% of infections in women and only 10% of infections in men cause symptoms. Being tested is the only way to know if you’re infected for sure—and to prevent the complications of an untreated case.
The Doctor Discussion Guide below can help you start that conversation with a healthcare professional.
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Engaging in unprotected sexHaving multiple sex partnersHaving another STI or having a partner who has an STIMen who have sex with men (MSM)Being HIV positiveHaving cervical ectopy
