• RGHGF Staff

The Big C and the little C: Asymptomatic C. trachomatis and its role in long-term diseases

Updated: Nov 29, 2019

Chlamydia is the most prevalent sexually transmitted infection in the United States. (1) For that reason, the microscopic organism that causes it, Chlamydia trachomatis, may sound familiar to you. Interestingly, C. trachomatis comes in many different bacterial strains, and the disease can manifest in a number of ways. (2) Although chlamydia most commonly presents itself in the genital tract, it can also appear in the eyes, lungs, and lymph nodes. (2) New research has also tied chlamydia to several different forms of cancer in recent years. (3),(4),(5)

Chlamydia is commonly mistaken for a urinary tract infection, and the manifestation of chlamydia in genitourinary diseases such as cervicitis (inflammation of the cervix), salpingitis (inflammation of the fallopian tubes), and urethritis (inflammation of the urethra) is well known. (2) Since many people with chlamydia are asymptomatic or exhibit very minor initial symptoms, C. trachomatis may seem relatively inconsequential. There is widespread belief that antibiotic treatment for C. trachomatis after symptoms develop eliminates any and all risk associated with the preceding disease. Unfortunately, that perception is not correct. The potential negative health outcomes resulting from chlamydia do not scale with the magnitude of the infection’s symptoms, meaning routine testing for the bacterial microspecies is crucial. It is an unfortunate reality. Did you know that pelvic inflammatory disease caused by asymptomatic chlamydia can cause infertility? (2) Or that untreated chlamydia is the most common infection-based cause of blindness? (2) If not, you’re in good company. Most people are not aware of these complications. Recent studies linking cancer with a medical history of chlamydia make it even more important to address misconceptions related to infections with C. trachomatis. (3),(4),(5)

Taking antibiotics after C. trachomatis symptoms are present may not eliminate all health complications associated with the bacteria.

One such cutting-edge study is outlined here. In research conducted at the National Cancer Institute and presented by Trabert et al. in 2018, a biomarker was found in women which tied chlamydia to an increased personal risk of ovarian cancer. (3),(4) Trabert et al. combined the results of two studies sampling over 400 women who had been diagnosed with cancer of the ovaries. (3),(4) Researchers found that women exhibiting antibodies against pgp3, a protein biomarker signaling a past infection with C. trachomatis, were approximately twice as likely to develop cancer of the ovaries. (3),(4) Another study in 2001 headed by Dr. Tarja Anttila at the University of Helsinki in Finland found a link between several serotypes of C. trachomatis and cervical cancer. (5) The term serotype refers to different bacterial subsets of a microorganism which are distinguishable from each other by the distinctive structures on the surface of the cells. Serotypes G, I, and D of chlamydia were correlated to 6.6-, 4.0-, and 2.7-fold increases in cervical cancer risk, respectively, with a clear risk factor being simultaneous infection with human papillomavirus (HPV). (5) These groundbreaking studies highlight a major public health risk, especially when one considers that women are three times as likely to be infected with C. trachomatis than men. (1)

At RGHGF, we are motivated to fund studies targeting infection-induced cancers. We believe that education and research on the topic of infection-induced cancers can provide us with critical information on diseases that ultimately save people’s lives. We invite you to join us as we pave the path toward a cancer-free world! #GoViralToEndBacterial


RGHGF Social Media Team



(2) Elwell, C. et al. Chlamydia cell biology and pathogenesis. Nat Rev Microbiol 2016, 14 (6): 385-400.


(4) Trabert, B. et al. Antibodies Against Chlamydia trachomatis and Ovarian Cancer Risk in Two Independent Populations. J Natl Cancer Inst 2019, 111 (2): 129-136.

(5) Anttila, T. et al. Serotypes of Chlamydia trachomatis and risk for development of cervical squamous cell carcinoma. JAMA 2001, 285 (1): 47-51.


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