Chlamydia

File:SOA-Chlamydia-trachomatis-female.jpg from chlamydia infection characterized by mucopurulent cervical discharge, redness, and inflammation]]

File:SOA-Chlamydia-trachomatis-male.jpg.]]

Chlamydial infection of the cervix (neck of the womb) is a sexually transmitted infection which has no symptoms for around 70% of women infected. The infection can be passed through vaginal, anal, oral, or manual sex. Of those who have an asymptomatic infection that is not detected by their doctor, approximately half will develop pelvic inflammatory disease (PID), a generic term for infection of the uterus, fallopian tubes, and/or ovaries. PID can cause scarring inside the reproductive organs, which can later cause serious complications, including chronic pelvic pain, difficulty becoming pregnant, ectopic (tubal) pregnancy, and other dangerous complications of pregnancy.

Chlamydia is known as the "silent epidemic", as at least 70% of genital C. trachomatis infections in women (and 50% in men) are asymptomatic at the time of diagnosis,[http://www.nhs.uk/conditions/Chlamydia/Pages/Introduction.aspx NHS Chlamydia page] {{webarchive|url=https://web.archive.org/web/20130116082623/http://www.nhs.uk/conditions/Chlamydia/Pages/Introduction.aspx |date=2013-01-16 }} and can linger for months or years before being discovered. Signs and symptoms may include abnormal vaginal bleeding or discharge, abdominal pain, painful sexual intercourse, fever, painful urination or the urge to urinate more often than usual (urinary urgency).{{cite journal | vauthors = Witkin SS, Minis E, Athanasiou A, Leizer J, Linhares IM | title = Chlamydia trachomatis: the Persistent Pathogen | journal = Clinical and Vaccine Immunology | volume = 24 | issue = 10 | date = October 2017 | pmid = 28835360 | pmc = 5629669 | doi = 10.1128/CVI.00203-17 }}

For sexually active women who are not pregnant, screening is recommended in those under 25 and others at risk of infection.{{cite journal | vauthors = Meyers D, Wolff T, Gregory K, Marion L, Moyer V, Nelson H, Petitti D, Sawaya GF | title = USPSTF recommendations for STI screening | journal = American Family Physician | volume = 77 | issue = 6 | pages = 819–824 | date = March 2008 | pmid = 18386598 | url = http://www.aafp.org/afp/20080315/819.html | access-date = 2008-03-17 | url-status = dead | archive-url = https://web.archive.org/web/20210828031335/https://www.aafp.org/afp/2008/0315/p819.html | archive-date = 2021-08-28 }} Risk factors include a history of chlamydial or other sexually transmitted infection, new or multiple sexual partners, and inconsistent condom use.{{cite journal | vauthors = ((U.S. Preventive Services Task Force)) | title = Screening for chlamydial infection: U.S. Preventive Services Task Force recommendation statement | journal = Annals of Internal Medicine | volume = 147 | issue = 2 | pages = 128–134 | date = July 2007 | pmid = 17576996 | doi = 10.7326/0003-4819-147-2-200707170-00172 | s2cid = 35816540 | url = http://www.ahrq.gov/clinic/uspstf07/chlamydia/chlamydiars.htm | url-status = live | doi-access = | archive-url = https://web.archive.org/web/20080303022755/http://www.ahrq.gov/clinic/uspstf07/chlamydia/chlamydiars.htm | archive-date = 2008-03-03 | url-access = subscription }} Guidelines recommend all women attending for emergency contraceptive are offered chlamydia testing, with studies showing up to 9% of women aged under 25 years had chlamydia.{{cite journal | vauthors = Yeung EY, Comben E, McGarry C, Warrington R | title = STI testing in emergency contraceptive consultations | journal = The British Journal of General Practice | volume = 65 | issue = 631 | pages = 63.1–64 | date = February 2015 | pmid = 25624285 | pmc = 4325454 | doi = 10.3399/bjgp15X683449 }}

In men, those with a chlamydial infection show symptoms of infectious inflammation of the urethra in about 50% of cases. Symptoms that may occur include: a painful or burning sensation when urinating, an unusual discharge from the penis, testicular pain or swelling, or fever. If left untreated, chlamydia in men can spread to the testicles causing epididymitis, which in rare cases can lead to sterility if not treated. Chlamydia is also a potential cause of prostatic inflammation in men, although the exact relevance in prostatitis is difficult to ascertain due to possible contamination from urethritis.{{cite journal | vauthors = Wagenlehner FM, Naber KG, Weidner W | title = Chlamydial infections and prostatitis in men | journal = BJU International | volume = 97 | issue = 4 | pages = 687–690 | date = April 2006 | pmid = 16536754 | doi = 10.1111/j.1464-410X.2006.06007.x | s2cid = 34481915 | doi-access = free }}

{{Main|Trachoma}}

File:SOA-conjunctivitis.jpg

Trachoma is a chronic conjunctivitis caused by Chlamydia trachomatis.{{cite book|title=Medical-surgical nursing : assessment and management of clinical problems| vauthors = Lewis SM |others=Bucher, Linda; Heitkemper, Margaret M. (Margaret McLean); Harding, Mariann|isbn=978-0-323-32852-4|edition=10th|location=St. Louis, Missouri|oclc=944472408|year = 2017}} It was once the leading cause of blindness worldwide, but its role diminished from 15% of blindness cases by trachoma in 1995 to 3.6% in 2002.{{cite journal | vauthors = Thylefors B, Négrel AD, Pararajasegaram R, Dadzie KY | title = Global data on blindness | journal = Bulletin of the World Health Organization | volume = 73 | issue = 1 | pages = 115–121 | year = 1995 | pmid = 7704921 | pmc = 2486591 | url = http://whqlibdoc.who.int/bulletin/1995/Vol73-No1/bulletin_1995_73(1)_115-121.pdf | url-status = dead | archive-url = https://web.archive.org/web/20080625212421/http://whqlibdoc.who.int/bulletin/1995/Vol73-No1/bulletin_1995_73(1)_115-121.pdf | archive-date = 2008-06-25 }}{{cite journal | vauthors = Resnikoff S, Pascolini D, Etya'ale D, Kocur I, Pararajasegaram R, Pokharel GP, Mariotti SP | title = Global data on visual impairment in the year 2002 | journal = Bulletin of the World Health Organization | volume = 82 | issue = 11 | pages = 844–851 | date = November 2004 | pmid = 15640920 | pmc = 2623053 | hdl = 10665/269277 }} The infection can be spread from eye to eye by fingers, shared towels or cloths, coughing and sneezing and eye-seeking flies.{{cite journal | vauthors = Mabey DC, Solomon AW, Foster A | title = Trachoma | journal = Lancet | volume = 362 | issue = 9379 | pages = 223–229 | date = July 2003 | pmid = 12885486 | doi = 10.1016/S0140-6736(03)13914-1 | s2cid = 208789262 }} Symptoms include mucopurulent ocular discharge, irritation, redness, and lid swelling. Newborns can also develop chlamydia eye infection through childbirth (see below). Using the SAFE strategy (acronym for surgery for in-growing or in-turned lashes, antibiotics, facial cleanliness, and environmental improvements), the World Health Organization aimed (unsuccessfully) for the global elimination of trachoma by 2020 (GET 2020 initiative).World Health Organization. [https://www.who.int/blindness/causes/trachoma/en/index.html Trachoma] {{webarchive|url=https://web.archive.org/web/20121021121158/http://www.who.int/blindness/causes/trachoma/en/index.html |date=2012-10-21 }}. Accessed March 17, 2008.{{cite journal | vauthors = Ngondi J, Onsarigo A, Matthews F, Reacher M, Brayne C, Baba S, Solomon AW, Zingeser J, Emerson PM | title = Effect of 3 years of SAFE (surgery, antibiotics, facial cleanliness, and environmental change) strategy for trachoma control in southern Sudan: a cross-sectional study | journal = Lancet | volume = 368 | issue = 9535 | pages = 589–595 | date = August 2006 | pmid = 16905023 | doi = 10.1016/S0140-6736(06)69202-7 | s2cid = 45018412 }} The updated World Health Assembly neglected tropical diseases road map (2021–2030) sets 2030 as the new timeline for global elimination.{{cite web |title=Trachoma |url=https://www.who.int/news-room/fact-sheets/detail/trachoma |access-date=2023-06-27 |website=www.who.int |language=en}}

Chlamydia may also cause reactive arthritis—the triad of arthritis, conjunctivitis and urethral inflammation—especially in young men. About 15,000 men develop reactive arthritis due to chlamydia infection each year in the U.S., and about 5,000 are permanently affected by it. It can occur in both sexes, though is more common in men.{{citation needed|date=September 2020}}

As many as half of all infants born to mothers with chlamydia will be born with the disease. Chlamydia can affect infants by causing spontaneous abortion; premature birth; conjunctivitis, which may lead to blindness; and pneumonia.{{cite web | title = STD Facts – Chlamydia | publisher = Center For Disease Control | date = December 16, 2014 | url = https://www.cdc.gov/std/Chlamydia/STDFact-Chlamydia.htm | access-date = 2015-07-24 | url-status = live | archive-url = https://web.archive.org/web/20150714002621/http://www.cdc.gov/std/chlamydia/stdfact-chlamydia.htm | archive-date = July 14, 2015 }} Conjunctivitis due to chlamydia typically occurs one week after birth (compared with chemical causes (within hours) or gonorrhea (2–5 days)).{{Citation | vauthors = Hansford P |title=Palliative Care in the United Kingdom |date=April 2010 |url=http://dx.doi.org/10.1093/med/9780195391343.003.0072 |work=Oxford Textbook of Palliative Nursing |pages=1265–1274 |publisher=Oxford University Press |doi=10.1093/med/9780195391343.003.0072 |isbn=978-0-19-539134-3 |access-date=15 December 2022|url-access=subscription }}

A different serovar of Chlamydia trachomatis is also the cause of lymphogranuloma venereum, an infection of the lymph nodes and lymphatics. It usually presents with genital ulceration and swollen lymph nodes in the groin, but it may also manifest as rectal inflammation, fever or swollen lymph nodes in other regions of the body.{{cite journal | vauthors = Williams D, Churchill D | title = Ulcerative proctitis in men who have sex with men: an emerging outbreak | journal = BMJ | volume = 332 | issue = 7533 | pages = 99–100 | date = January 2006 | pmid = 16410585 | pmc = 1326936 | doi = 10.1136/bmj.332.7533.99 }}

Chlamydia can be transmitted during vaginal, anal, oral, or manual sex or direct contact with infected tissue such as conjunctiva. Chlamydia can also be passed from an infected mother to her baby during vaginal childbirth. It is assumed that the probability of becoming infected is proportionate to the number of bacteria one is exposed to.{{cite journal | vauthors = Gambhir M, Basáñez MG, Turner F, Kumaresan J, Grassly NC | title = Trachoma: transmission, infection, and control | journal = The Lancet. Infectious Diseases | volume = 7 | issue = 6 | pages = 420–427 | date = June 2007 | pmid = 17521595 | doi = 10.1016/S1473-3099(07)70137-8 }}

Chlamydia bacteria have the ability to establish long-term associations with host cells. When an infected host cell is starved for various nutrients such as amino acids (for example, tryptophan),{{cite journal | vauthors = Leonhardt RM, Lee SJ, Kavathas PB, Cresswell P | title = Severe tryptophan starvation blocks onset of conventional persistence and reduces reactivation of Chlamydia trachomatis | journal = Infection and Immunity | volume = 75 | issue = 11 | pages = 5105–5117 | date = November 2007 | pmid = 17724071 | pmc = 2168275 | doi = 10.1128/IAI.00668-07 }} iron, or vitamins, this has a negative consequence for chlamydia bacteria since the organism is dependent on the host cell for these nutrients. Long-term cohort studies indicate that approximately 50% of those infected clear within a year, 80% within two years, and 90% within three years.{{cite journal | vauthors = Fairley CK, Gurrin L, Walker J, Hocking JS | title = "Doctor, how long has my Chlamydia been there?" Answer: ".... years" | journal = Sexually Transmitted Diseases | volume = 34 | issue = 9 | pages = 727–728 | date = September 2007 | pmid = 17717486 | doi = 10.1097/OLQ.0b013e31812dfb6e | doi-access = free }}

The starved chlamydia bacteria can enter a persistent growth state where they stop cell division and become morphologically aberrant by increasing in size.{{cite journal | vauthors = Mpiga P, Ravaoarinoro M | title = Chlamydia trachomatis persistence: an update | journal = Microbiological Research | volume = 161 | issue = 1 | pages = 9–19 | year = 2006 | pmid = 16338585 | doi = 10.1016/j.micres.2005.04.004 | doi-access = }} Persistent organisms remain viable as they are capable of returning to a normal growth state once conditions in the host cell improve.{{cite book | vauthors = Kushwaha AK |url=https://books.google.com/books?id=r4vtDwAAQBAJ&dq=persistent+organisms+remain+viable+as+they+are+capable+of+returning+to+a+normal+growth+state+once+conditions+in+the+host+cell+improve&pg=PA202 |title=Textbook of Microbiology |date=2020-07-26 |publisher=Dr. A.K KUSHWAHA |language=en}}

There is debate as to whether persistence has relevance: some believe that persistent chlamydia bacteria are the cause of chronic chlamydial diseases. Some antibiotics such as β-lactams have been found to induce a persistent-like growth state.{{cite journal | vauthors = Bayramova F, Jacquier N, Greub G | title = Insight in the biology of Chlamydia-related bacteria | journal = Microbes and Infection | volume = 20 | issue = 7–8 | pages = 432–440 | year = 2018 | pmid = 29269129 | doi = 10.1016/j.micinf.2017.11.008 | publisher = Elsevier | doi-access = free }}{{cite book| vauthors = Klöckner A, Bühl H, Viollier P, Henrichfreise B | title=Biology of Chlamydia | volume=412 | editor=Häcker, Georg | chapter=Deconstructing the Chlamydial Cell Wall | year=2018 | publisher=Springer International Publishing | location=Cham | pages=1–33|doi=10.1007/82_2016_34| pmid=27726004 |isbn=978-3-319-71232-1| series=Current Topics in Microbiology and Immunology }}

File:ChlamydiaTrachomatisEinschlusskörperchen.jpg]]

The diagnosis of genital chlamydial infections evolved rapidly from the 1990s through 2006. Nucleic acid amplification tests (NAAT), such as polymerase chain reaction (PCR), transcription mediated amplification (TMA), and the DNA strand displacement amplification (SDA) now are the mainstays. NAAT for chlamydia may be performed on swab specimens sampled from the cervix (women) or urethra (men), on self-collected vaginal swabs, or on voided urine.{{cite journal | vauthors = Gaydos CA, Theodore M, Dalesio N, Wood BJ, Quinn TC | title = Comparison of three nucleic acid amplification tests for detection of Chlamydia trachomatis in urine specimens | journal = Journal of Clinical Microbiology | volume = 42 | issue = 7 | pages = 3041–3045 | date = July 2004 | pmid = 15243057 | pmc = 446239 | doi = 10.1128/JCM.42.7.3041-3045.2004 | citeseerx = 10.1.1.335.7713 }} NAAT has been estimated to have a sensitivity of approximately 90% and a specificity of approximately 99%, regardless of sampling from a cervical swab or by urine specimen.{{cite journal | vauthors = Haugland S, Thune T, Fosse B, Wentzel-Larsen T, Hjelmevoll SO, Myrmel H | title = Comparing urine samples and cervical swabs for Chlamydia testing in a female population by means of Strand Displacement Assay (SDA) | journal = BMC Women's Health | volume = 10 | issue = 1 | pages = 9 | date = March 2010 | pmid = 20338058 | pmc = 2861009 | doi = 10.1186/1472-6874-10-9 | doi-access = free }} In women seeking treatment in a sexually transmitted infection clinic where a urine test is negative, a subsequent cervical swab has been estimated to be positive in approximately 2% of the time.

At present, the NAATs have regulatory approval only for testing urogenital specimens, although rapidly evolving research indicates that they may give reliable results on rectal specimens.

Because of improved test accuracy, ease of specimen management, convenience in specimen management, and ease of screening sexually active men and women, the NAATs have largely replaced culture, the historic gold standard for chlamydia diagnosis, and the non-amplified probe tests. The latter test is relatively insensitive, successfully detecting only 60–80% of infections in asymptomatic women, and often giving falsely-positive results. Culture remains useful in selected circumstances and is currently the only assay approved for testing non-genital specimens. Other methods also exist including: ligase chain reaction (LCR), direct fluorescent antibody resting, enzyme immunoassay, and cell culture.{{cite web|url=https://www.cdc.gov/mmwr/preview/mmwrhtml/rr6302a1.htm|title=Recommendations for the Laboratory-Based Detection of Chlamydia trachomatis and Neisseria gonorrhoeae — 2014|website=Centers for Disease Control and Prevention|access-date=2016-06-12|url-status=live|archive-url=https://web.archive.org/web/20160627175218/http://www.cdc.gov/mmwr/preview/mmwrhtml/rr6302a1.htm|archive-date=2016-06-27}}

The swab sample for chlamydial infections does not show difference whether the sample was collected in home or in clinic in terms of numbers of patient treated. The implications in cured patients, reinfection, partner management, and safety are unknown.{{cite journal | vauthors = Fajardo-Bernal L, Aponte-Gonzalez J, Vigil P, Angel-Müller E, Rincon C, Gaitán HG, Low N | title = Home-based versus clinic-based specimen collection in the management of Chlamydia trachomatis and Neisseria gonorrhoeae infections | journal = The Cochrane Database of Systematic Reviews | volume = 2015 | issue = 9 | pages = CD011317 | date = September 2015 | pmid = 26418128 | pmc = 8666088 | doi = 10.1002/14651858.CD011317.pub2 | collaboration = Cochrane STI Group }}

Rapid point-of-care tests are, as of 2020, not thought to be effective for diagnosing chlamydia in men of reproductive age and non-pregnant women because of high false-negative rates.{{cite journal | vauthors = Grillo-Ardila CF, Torres M, Gaitán HG | title = Rapid point of care test for detecting urogenital Chlamydia trachomatis infection in nonpregnant women and men at reproductive age | journal = The Cochrane Database of Systematic Reviews | volume = 1 | issue = 1 | pages = CD011708 | date = January 2020 | pmid = 31995238 | pmc = 6988850 | doi = 10.1002/14651858.CD011708.pub2 }}

Prevention is by not having sex, the use of condoms, or having sex with only one other person, who is not infected.

For sexually active women who are not pregnant, screening is recommended in those under 25 and others at risk of infection. Risk factors include a history of chlamydial or other sexually transmitted infection, new or multiple sexual partners, and inconsistent condom use. For pregnant women, guidelines vary: screening women with age or other risk factors is recommended by the U.S. Preventive Services Task Force (USPSTF) (which recommends screening women under 25) and the American Academy of Family Physicians (which recommends screening women aged 25 or younger). The American College of Obstetricians and Gynecologists recommends screening all at risk, while the Centers for Disease Control and Prevention recommend universal screening of pregnant women. The USPSTF acknowledges that in some communities there may be other risk factors for infection, such as ethnicity. Evidence-based recommendations for screening initiation, intervals and termination are currently not possible. For men, the USPSTF concludes evidence is currently insufficient to determine if regular screening of men for chlamydia is beneficial. They recommend regular screening of men who are at increased risk for HIV or syphilis infection. A Cochrane review found that the effects of screening are uncertain in terms of chlamydia transmission but that screening probably reduces the risk of pelvic inflammatory disease in women.{{cite journal | vauthors = Low N, Redmond S, Uusküla A, van Bergen J, Ward H, Andersen B, Götz H | title = Screening for genital chlamydia infection | journal = The Cochrane Database of Systematic Reviews | volume = 2016 | issue = 9 | pages = CD010866 | date = September 2016 | pmid = 27623210 | pmc = 6457643 | doi = 10.1002/14651858.CD010866.pub2 }}

In the United Kingdom the National Health Service (NHS) aims to:

1. Prevent and control chlamydia infection through early detection and treatment of asymptomatic infection;
2. Reduce onward transmission to sexual partners;
3. Prevent the consequences of untreated infection;
4. Test at least 25 percent of the sexually active under 25 population annually.{{cite web|url=http://www.chlamydiascreening.nhs.uk/ps/data/data_tables.html|title=National Chlamydia Screening Programme Data tables|access-date=2009-08-28|website=www.chlamydiascreening.nhs.uk|archive-url=https://web.archive.org/web/20090504185725/http://www.chlamydiascreening.nhs.uk/ps/data/data_tables.html|archive-date=2009-05-04|url-status=dead}}
5. Retest after treatment.{{cite journal | vauthors = Desai M, Woodhall SC, Nardone A, Burns F, Mercey D, Gilson R | title = Active recall to increase HIV and STI testing: a systematic review | journal = Sexually Transmitted Infections | volume = 91 | issue = 5 | pages = 314–323 | date = August 2015 | pmid = 25759476 | doi = 10.1136/sextrans-2014-051930 | doi-access = free | quote = Strategies for improved follow up care include the use of text messages and emails from those who provided treatment. }}

C. trachomatis infection can be effectively cured with antibiotics. Guidelines recommend azithromycin, doxycycline, erythromycin, levofloxacin or ofloxacin.{{cite book|veditors=Eliopoulos GM, Gilbert DN, Moellering RC|title=The Sanford guide to antimicrobial therapy 2011|publisher=Antimicrobial Therapy, Inc.|location=Sperryville, VA|isbn=978-1-930808-65-2|pages=[https://archive.org/details/sanfordguidetoan00davi_0/page/20 20]|url=https://archive.org/details/sanfordguidetoan00davi_0/page/20|year=2015}} In men, doxycycline (100 mg twice a day for 7 days) is probably more effective than azithromycin (1 g single dose) but evidence for the relative effectiveness of antibiotics in women is very uncertain.{{cite journal | vauthors = Páez-Canro C, Alzate JP, González LM, Rubio-Romero JA, Lethaby A, Gaitán HG | title = Antibiotics for treating urogenital Chlamydia trachomatis infection in men and non-pregnant women | journal = The Cochrane Database of Systematic Reviews | volume = 1 | issue = 1 | pages = CD010871 | date = January 2019 | pmid = 30682211 | pmc = 6353232 | doi = 10.1002/14651858.CD010871.pub2 }} Agents recommended during pregnancy include erythromycin or amoxicillin.{{cite journal | vauthors = Miller KE | title = Diagnosis and treatment of Chlamydia trachomatis infection | journal = American Family Physician | volume = 73 | issue = 8 | pages = 1411–1416 | date = April 2006 | pmid = 16669564 | url = http://www.aafp.org/afp/2006/0415/p1411.html | access-date = 2010-10-30 | url-status = live | archive-url = https://web.archive.org/web/20111127054457/http://www.aafp.org/afp/2006/0415/p1411.html | archive-date = November 27, 2011 }}

An option for treating sexual partners of those with chlamydia or gonorrhea includes patient-delivered partner therapy (PDT or PDPT), which is the practice of treating the sex partners of index cases by providing prescriptions or medications to the patient to take to his/her partner without the health care provider first examining the partner.[https://www.cdc.gov/std/treatment/EPTFinalReport2006.pdf Expedited Partner Therapy in the Management of Sexually Transmitted Diseases (2 February 2006)] {{webarchive|url=https://web.archive.org/web/20170729185320/https://www.cdc.gov/std/treatment/eptfinalreport2006.pdf |archive-url=https://web.archive.org/web/20060321102011/http://www.cdc.gov/std/treatment/EPTFinalReport2006.pdf |archive-date=2006-03-21 |url-status=live |date=29 July 2017 }} U.S. Department of Health and Human Services Public Health Service. Centers for Disease Control and Prevention National Center for HIV, STD, and TB Prevention

Following treatment people should be tested again after three months to check for reinfection. Test of cure may be false-positive due to the limitations of NAAT in a bacterial (rather than a viral) context, since targeted genetic material may persist in the absence of viable organisms.{{cite journal | vauthors = Dukers-Muijrers N, Morré S, Speksnijder A, Sande M, Hoebe C | title = Chlamydia trachomatis Test-of-Cure Cannot Be Based on a Single Highly Sensitive Laboratory Test Taken at Least 3 Weeks after Treatment | journal = PLOS ONE | volume = 7 | issue = 3 | pages = e34108 | date = 28 March 2012 | pmid = 22470526 | pmc = 3314698 | doi = 10.1371/journal.pone.0034108 | doi-access = free | bibcode = 2012PLoSO...734108D }}

File:Chlamydia world map - DALY - WHO2004.svg (DALY) for chlamydia per 100,000 inhabitants in 2004{{cite web |url=https://www.who.int/healthinfo/global_burden_disease/estimates_country/en/index.html |title=WHO Disease and injury country estimates |year=2004 |work=World Health Organization |access-date=Nov 11, 2009 |url-status=live |archive-url=https://web.archive.org/web/20091111101009/http://www.who.int/healthinfo/global_burden_disease/estimates_country/en/index.html |archive-date=2009-11-11 }}{{Div col|small=yes|colwidth=10em}}

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Globally, as of 2015, sexually transmitted chlamydia affects approximately 61 million people. It is more common in women (3.8%) than men (2.5%).{{cite journal | vauthors = Vos T, Flaxman AD, Naghavi M, Lozano R, Michaud C, Ezzati M, Shibuya K, Salomon JA, Abdalla S, Aboyans V, Abraham J, Ackerman I, Aggarwal R, Ahn SY, Ali MK, Alvarado M, Anderson HR, Anderson LM, Andrews KG, Atkinson C, Baddour LM, Bahalim AN, Barker-Collo S, Barrero LH, Bartels DH, Basáñez MG, Baxter A, Bell ML, Benjamin EJ, Bennett D, Bernabé E, Bhalla K, Bhandari B, Bikbov B, Bin Abdulhak A, Birbeck G, Black JA, Blencowe H, Blore JD, Blyth F, Bolliger I, Bonaventure A, Boufous S, Bourne R, Boussinesq M, Braithwaite T, Brayne C, Bridgett L, Brooker S, Brooks P, Brugha TS, Bryan-Hancock C, Bucello C, Buchbinder R, Buckle G, Budke CM, Burch M, Burney P, Burstein R, Calabria B, Campbell B, Canter CE, Carabin H, Carapetis J, Carmona L, Cella C, Charlson F, Chen H, Cheng AT, Chou D, Chugh SS, Coffeng LE, Colan SD, Colquhoun S, Colson KE, Condon J, Connor MD, Cooper LT, Corriere M, Cortinovis M, de Vaccaro KC, Couser W, Cowie BC, Criqui MH, Cross M, Dabhadkar KC, Dahiya M, Dahodwala N, Damsere-Derry J, Danaei G, Davis A, De Leo D, Degenhardt L, Dellavalle R, Delossantos A, Denenberg J, Derrett S, Des Jarlais DC, Dharmaratne SD, Dherani M, Diaz-Torne C, Dolk H, Dorsey ER, Driscoll T, Duber H, Ebel B, Edmond K, Elbaz A, Ali SE, Erskine H, Erwin PJ, Espindola P, Ewoigbokhan SE, Farzadfar F, Feigin V, Felson DT, Ferrari A, Ferri CP, Fèvre EM, Finucane MM, Flaxman S, Flood L, Foreman K, Forouzanfar MH, Fowkes FG, Franklin R, Fransen M, Freeman MK, Gabbe BJ, Gabriel SE, Gakidou E, Ganatra HA, Garcia B, Gaspari F, Gillum RF, Gmel G, Gosselin R, Grainger R, Groeger J, Guillemin F, Gunnell D, Gupta R, Haagsma J, Hagan H, Halasa YA, Hall W, Haring D, Haro JM, Harrison JE, Havmoeller R, Hay RJ, Higashi H, Hill C, Hoen B, Hoffman H, Hotez PJ, Hoy D, Huang JJ, Ibeanusi SE, Jacobsen KH, James SL, Jarvis D, Jasrasaria R, Jayaraman S, Johns N, Jonas JB, Karthikeyan G, Kassebaum N, Kawakami N, Keren A, Khoo JP, King CH, Knowlton LM, Kobusingye O, Koranteng A, Krishnamurthi R, Lalloo R, Laslett LL, Lathlean T, Leasher JL, Lee YY, Leigh J, Lim SS, Limb E, Lin JK, Lipnick M, Lipshultz SE, Liu W, Loane M, Ohno SL, Lyons R, Ma J, Mabweijano J, MacIntyre MF, Malekzadeh R, Mallinger L, Manivannan S, Marcenes W, March L, Margolis DJ, Marks GB, Marks R, Matsumori A, Matzopoulos R, Mayosi BM, McAnulty JH, McDermott MM, McGill N, McGrath J, Medina-Mora ME, Meltzer M, Mensah GA, Merriman TR, Meyer AC, Miglioli V, Miller M, Miller TR, Mitchell PB, Mocumbi AO, Moffitt TE, Mokdad AA, Monasta L, Montico M, Moradi-Lakeh M, Moran A, Morawska L, Mori R, Murdoch ME, Mwaniki MK, Naidoo K, Nair MN, Naldi L, Narayan KM, Nelson PK, Nelson RG, Nevitt MC, Newton CR, Nolte S, Norman P, Norman R, O'Donnell M, O'Hanlon S, Olives C, Omer SB, Ortblad K, Osborne R, Ozgediz D, Page A, Pahari B, Pandian JD, Rivero AP, Patten SB, Pearce N, Padilla RP, Perez-Ruiz F, Perico N, Pesudovs K, Phillips D, Phillips MR, Pierce K, Pion S, Polanczyk GV, Polinder S, Pope CA, Popova S, Porrini E, Pourmalek F, Prince M, Pullan RL, Ramaiah KD, Ranganathan D, Razavi H, Regan M, Rehm JT, Rein DB, Remuzzi G, Richardson K, Rivara FP, Roberts T, Robinson C, De Leòn FR, Ronfani L, Room R, Rosenfeld LC, Rushton L, Sacco RL, Saha S, Sampson U, Sanchez-Riera L, Sanman E, Schwebel DC, Scott JG, Segui-Gomez M, Shahraz S, Shepard DS, Shin H, Shivakoti R, Singh D, Singh GM, Singh JA, Singleton J, Sleet DA, Sliwa K, Smith E, Smith JL, Stapelberg NJ, Steer A, Steiner T, Stolk WA, Stovner LJ, Sudfeld C, Syed S, Tamburlini G, Tavakkoli M, Taylor HR, Taylor JA, Taylor WJ, Thomas B, Thomson WM, Thurston GD, Tleyjeh IM, Tonelli M, Towbin JA, Truelsen T, Tsilimbaris MK, Ubeda C, Undurraga EA, van der Werf MJ, van Os J, Vavilala MS, Venketasubramanian N, Wang M, Wang W, Watt K, Weatherall DJ, Weinstock MA, Weintraub R, Weisskopf MG, Weissman MM, White RA, Whiteford H, Wiersma ST, Wilkinson JD, Williams HC, Williams SR, Witt E, Wolfe F, Woolf AD, Wulf S, Yeh PH, Zaidi AK, Zheng ZJ, Zonies D, Lopez AD, Murray CJ, AlMazroa MA, Memish ZA | title = Years lived with disability (YLDs) for 1160 sequelae of 289 diseases and injuries 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010 | journal = Lancet | volume = 380 | issue = 9859 | pages = 2163–2196 | date = December 2012 | pmid = 23245607 | pmc = 6350784 | doi = 10.1016/S0140-6736(12)61729-2 }} In 2015 it resulted in about 200 deaths.

In the United States about 1.6 million cases were reported in 2016. The CDC estimates that if one includes unreported cases there are about 2.9 million each year.{{cite web|title=Detailed STD Facts – Chlamydia|url=https://www.cdc.gov/std/chlamydia/stdfact-chlamydia-detailed.htm|website=Centers for Disease Control and Prevention|access-date=14 January 2018|language=en-us|date=20 September 2017}} It affects around 2% of young people.{{cite journal | vauthors = Torrone E, Papp J, Weinstock H | title = Prevalence of Chlamydia trachomatis genital infection among persons aged 14-39 years--United States, 2007-2012 | journal = MMWR. Morbidity and Mortality Weekly Report | volume = 63 | issue = 38 | pages = 834–838 | date = September 2014 | pmid = 25254560 | pmc = 4584673 }} Chlamydial infection is the most common bacterial sexually transmitted infection in the UK.{{cite web|title=Chlamydia|url=http://www.hpa.org.uk/Publications/InfectiousDiseases/Factsheets/factChlamydia/|publisher=UK Health Protection Agency|access-date=31 August 2012|url-status=dead|archive-url=https://web.archive.org/web/20120913212016/http://www.hpa.org.uk/Publications/InfectiousDiseases/Factsheets/factChlamydia|archive-date=13 September 2012}}

Chlamydia causes more than 250,000 cases of epididymitis in the U.S. each year. Chlamydia causes 250,000 to 500,000 cases of PID every year in the United States. Women infected with chlamydia are up to five times more likely to become infected with HIV, if exposed.

{{Clear}}

• Chlamydia research

{{Reflist}}

{{commons category|Chlamydia infections}}

• [https://www.who.int/news-room/fact-sheets/detail/chlamydia WHO fact sheet on chlamydia]
• [https://www.cdc.gov/chlamydia/about/ About Chlamydia] from the CDC

{{Offline|med}}

{{STD/STI}}

{{Bacterial cutaneous infections}}

{{Medical resources

| ICD11 = {{ICD11|1A80}}, {{ICD11|1A81}}, {{ICD11|1C20}}–{{ICD11|1C23}}

| ICD10 = {{ICD10|A55}}, {{ICD10|A56}}, {{ICD10|A70-A74}}

| ICD9 = {{ICD9|099.41}}, {{ICD9|483.1}}

| ICDO =

| OMIM =

| DiseasesDB = 2384

| MedlinePlus =

| eMedicineSubj = med

| eMedicineTopic = 340

| MeshID = D002690

}}

{{Authority control}}

{{DEFAULTSORT:Chlamydia Infection}}

Category:Sexually transmitted diseases and infections

Category:Chlamydiota

Category:Infectious causes of cancer

Category:Wikipedia medicine articles ready to translate

Category:Vaccine-preventable diseases