What Is Chlamydia? What Causes Chlamydia?

Chlamydia, or chlamydial infection, is a sexually transmitted infection (STI) caused by Chlamydia trachomatis (C. trachomatis), a bacterium that only infects humans. Although we usually think of the sexually transmitted disease (STD), chlamydial infection refers to infection caused by any species of the Chlamydiaceae bacterial family.

Chlamydia is a common infectious cause of genital and eye diseases in humans. It is the leading bacterial STI worldwide.

USA - Approximately 2.3 million people in the USA are currently infected with Chlamydia. Less than half of the women in the U.S. who are at risk for Chlamydia are being screened for the sexually transmitted infection, according to the CDC (Centers for Disease Control and Prevention).

Recurring Chlamydial infections are prevalent in young women ages 14-19, according to a Yale Department of Epidemiology and Public Health study. Over half of the study's 411 participants were initially diagnosed with chlamydia and then, in a rate higher than previously recorded, nearly 30 percent reported repeated infection throughout the four-year Project.


UK - In the UK the number of new cases diagnosed each year has been steadily rising since the mid-1990s - it is now the most commonly diagnosed STI in the country. In 2004, 104,733 new diagnoses of Chlamydia were made - in 2005 there were 109,958 new diagnoses. According to the NHS (National Health Service), UK, women under the age of 25 who are sexually active have a 10% chance of becoming infected with C. trachomatis. The peak age range for male infection risk is 20 to 30 years.

Chlamydia is an easily treatable disease which, unfortunately, often has no early symptoms and is not treated until complications have emerged.

According to the World Health Organization (WHO) 15% of blindness cases worldwide were caused by Chlamydia conjunctivitis (trachoma) in 1995, dropping to 3.6% in 2002.

What is the difference between an STI and an STD?

A sexually transmitted infection (STI) is the infection, the entering of the bacterium, virus, or parasite into the human body (host).

When symptoms appear it is called a sexually transmitted disease (STD).

A person may have no symptoms and have an STI, while a person with an STD can't (STDs have symptoms). In short, everyone who has an STD also has an STI, but not everyone who has an STI has an STD - because not everyone has symptoms.

An STI is caused by a bacterium, virus or parasite from sexual intercourse or a sexual encounter. An STD is caused by an STI with a bacterium, virus or parasite from sexual intercourse or a sexual encounter.

What are sexually transmitted infections?

Sexually transmitted infections (STIs) are infections that spread primarily through person-to-person sexual contact. The word "primarily" is used here because sexual contact is the main or original source of infection and the main means of transmission; however, in some cases the infected person may pass the infection on without sexual contact, as might be the case when giving birth (mother infects baby), or if an infected person donates blood which is later used in a blood transfusion and infects a patient in hospital.

There are over 30 different sexually transmissible bacteria, viruses and parasites. Below is a list of the most common ones:

Common sexually transmissible bacterial infections


• Neisseria gonorrhoeae - causes gonorrhea or gonococcal infection.
• Chlamydia trachomatis - causes chlamydial infections.
• Treponema pallidum - causes syphilis.
• Haemophilus ducreyi - causes chancroid.
• Klebsiella granulomatis - previously known as Calymmatobacterium granulomatis causes granuloma inguinale or donovanosis.

Common sexually transmissible viral infections


• Human immunodeficiency virus - causes AIDS.
• Herpes simplex virus type 2 - causes genital herpes.
• Human papillomavirus - causes genital warts. 15 subtypes lead to cervical cancer.
• Hepatitis B virus - causes hepatitis and chronic cases may lead to cancer of the liver.
• Cytomegalovirus - causes inflammation in a number of organs including the brain, the eye, and the bowel.

Sexually transmissible parasitic organisms


• Trichomonas vaginalis - causes vaginal trichomoniasis, also known as "trich".
• Candida albicans - causes vulvovaginitis in women; inflammation of the glans penis and foreskin in men (balano-posthitis).

What are the symptoms of Chlamydia?

Some people refer to Chlamydia as a silent disease because there are rarely any noticeable symptoms initially. Experts say that approximately 50% of infected men and 70% of infected women will have no symptoms at all. Others will have such minor symptoms that the infection goes unnoticed.

Women

Genital Chlamydia does not usually present symptoms in women. However, there may be non-specific symptoms, including:

• Cystitis - inflammation of the bladder.
• A change in vaginal discharge.
• Slight lower abdominal pain.

Women with any of the symptoms mentioned above should visit their GP or family planning doctor. If a Chlamydia test is not offered, ask for one. If Chlamydia is not treated the following symptoms may emerge later:

• Pelvic pain.
• Pain during sexual intercourse - may be every time, or intermittently.
• Bleeding between menstrual periods.

See "Complications of Chlamydia" below for more symptoms in women.

Men - symptoms in men are usually from complications (see "Complications of Chlamydia" below).

What are the causes of Chlamydia?

Chlamydia is a sexually transmitted infection (STI). Chlamydia may be transmitted by:

• Having unprotected vaginal sex with an infected person.
• Having unprotected anal sex with an infected person.
• Having unprotected oral sex with an infected person.
• Having genital contact with an infected person.

As chlamydial infection often presents no symptoms, an infected person may pass it on to his/her sexual partner without knowing.

Childbirth - an infected mother can pass the infection on to her baby during childbirth. Sometimes the infection may lead to complications for the infant, such as pneumonia.

Chlamydia cannot be transmitted through:

• Contact with a toilet seat that has been used by an infected person.
• Sharing a sauna with infected people.
• Sharing a swimming pool with infected people.
• Touching a surface that an infected person had previously touched or coughed/sneezed on.
• Standing close to an infected person, inhaling the air after they have coughed or sneezed.
• Sharing an office with an infected colleague.

Chlamydophila pneumonia, which causes respiratory infections, including pneumonia, is different from C. trachomatis, the sexually transmitted infection. Chlamydophila pneumonia is an airborne bacterium and is not a sexually transmitted infection. This article focuses entirely on C. trachomatis.

A C. trachomatis variety causes LGV (lymphogranuloma venereum), another sexually transmitted disease which is more common in Africa, Southeast Asia, Central/South America and the Caribbean. Signs and symptoms include genital sores, fever and swollen nymph nodes in the groin area. In Europe LGV cases have increased, especially among homosexual and bisexual males. US authorities have expressed concern that LGV is slowly emerging in America too.

How is Chlamydia diagnosed?

Screening

As chlamydial infection frequently presents no symptoms health authorities in most nations recommend screening for some people. The US Centers for Disease Control and Prevention (CDC) recommends Chlamydia screening for:

• Women aged below 25 years - authorities recommend annual screening. Women under the age of 25 who are sexually active are at the highest risk of becoming infected.


• Pregnant women - Chlamydia screening should be done during the first prenatal exam. Women who have had several sexual partners should have another test before the expected delivery date.


• High risk males and females - regular screening is recommended for males and females who either do not regularly use a condom, those who have multiple sex partners, and people who have another sexually transmitted disease.

How is Chlamydia screening done?

• Women - traditionally the doctor or nurse would take a sample of the discharge from the cervix (swab). This was sent to the lab for culture or Chlamydia antigen testing. Nowadays women more commonly will do the procedure at home, either with a urine sample, or by taking a swab form the lower vagina. The swab is placed in a container and sent to a laboratory.


• Men - traditionally, a thin swab was inserted into the end of the urethra through the penis. The sample would be sent to the lab for testing. A urine test is more commonly used today. Although the urine test is not as reliable as using a swab, it is easier to do and painless. Scientists at the University of Cambridge, England, devised a new urine test can detect 84% of infections.

Sometimes a swab of the anus may be done.

Most countries have clinics that specialize in genito-urinary medicine (GUM). In the UK they are known as STI clinics or GUM clinics. UK GUM clinics have dedicated testing facilities, and often help people in contacting previous sexual partners so that they may also be tested and have treatment. Most GP practices also provide STI testing and advice.

What are the treatment options for Chlamydia?

Antibiotics are at least 95% effective in treating Chlamydia if the patient adheres to the doctor's instructions. In most cases they will be pills that the patient swallows. Treatment may consist of:

• Azithromycin (brand names APO-Azithromycin in Canada; Zithromax in Finland, Italy, UK, USA, Australia, Portugal, S. Africa, Canada, Thailand and Belgium; Zithromac in Japan; Vinzam / Zitromax in Spain; Zmax/Sumamed in Croatia; ATM, Aztrin, Zitrocin, Azibiot, Azifine, AziCip, Azi Sandoz, Aziswift in India, Azocam and Bactizith in Pakistan) - the patient receives just one dose.


• Doxycycline (brand names may be Vibramycin, Monodox, Microdox, Periostat, Vibra-Tabs, Oracea, Doryx, Vibrox, Adoxa, Doxyhexal, Doxylin, and Atridox) - the patient takes one or two tablets daily for one or two weeks. It is important that the course is completed if you don't want the infection to return.

Some patients, such as pregnant women, may be given alternative antibiotics. Doxycycline or tetracycline may affect the development of the baby's bones and teeth.

The following antibiotics may also be used: amoxicillin, ampicillin, clarithromycin, lymecycline, minocycline, ofloxacin, pivampicillin, erythromycin and rifampicin.

People taking the contraceptive pill or contraceptive patch will need to use additional contraception, such as condoms, because the antibiotics may interfere with their effectiveness. Ask your doctor how long you have to do this for.

Some patients may have the following side effects when they take the antibiotics:

• Diarrhea
• Stomach pain
• Stomach upset
• Nausea

In most cases the side effects will be mild. Patients taking doxycycline may have a skin rash if they are exposed to sunlight.

What are the complications of Chlamydia?

Early diagnosis and treatment greatly reduces the risk of complications. Complications can be prevented with regular screening, or by seeking medical attention as soon as symptoms appear.

Women - Chlamydia complications

• Pelvic Inflammatory Disease (PID) - Pelvic inflammatory disease is commonly caused by chlamydial infections. PID is an infection of the ovaries, fallopian tubes and uterus. PID significantly raises the risk of ectopic pregnancy - the fertilized egg does not settle and grow in the uterus; in most cases it will grow in the fallopian tubes, but may also grow in the ovary, cervix, or abdominal cavity. PID may also cause persistent pelvic pain.


• Cervicitis - inflammation of the cervix (neck of the womb). Symptoms may include a vaginal discharge which may contain pus, pain during intercourse, frequent urination, burning pain when urinating. In chronic cervicitis the cervix may swell and cysts may develop. The cysts may become infected. Some patients experience backache, deep pelvic pain, and constant vaginal discharge.


• Salpingitis - inflammation of the fallopian tubes. If the fallopian tubes become blocked the egg will not be able to pass along or enter the fallopian tube. There is a significant increase of ectopic pregnancy. Microsurgery is sometimes performed to clear the blockage.


• Bartholinitis - inflammation of the Bartholin gland, which produces the lubricating mucus to make sexual intercourse easier. The gland is located in either side of the vaginal opening. Chlamydial infection may cause it to become blocked and infected, leading to a Bartholin cyst. The cyst may develop into an abscess.

Men - Chlamydia complications

• Fertility - Spanish researchers found that Chlamydia can affect the quality of male sperm.


• Urethritis - the urethra, a tube which carries urine from the bladder to the end of the penis, becomes inflamed. Symptoms include a discharge with yellow pus, mucus with pus, or just clear mucus at the opening (the hole at the end of the penis where urine comes out). Untreated urethritis can lead to urethral stricture - the urethra narrows which makes it harder to urinate properly, creating pressure which may damage the kidneys.


• Epididymitis - Inflammation of the epididymis, a structure inside the scrotum (sack that holds the testicles) attached to the backside of the testis (testicles). Signs and symptoms include red, swollen and warm scrotum, testicle pain and tenderness which is usually on one side, painful urination, frequent urination, painful ejaculation, painful intercourse before ejaculation, lump in testicle, swollen inguinal nodes (lymph nodes in the groin), discharge from penis, and blood in the semen.


• Reiter syndrome - a chronic type of inflammatory arthritis. This can include just arthritis, conjunctivitis (inflammation of the eyes), and inflammation of the genital, urinary and gastrointestinal systems. The body's organs as well as the joints can become affected. Serious inflammation can affect the eyes, kidneys, heart, skin, lungs and mouth.

Prevention of Chlamydia

• Condoms - condoms significantly reduce the risk of becoming infected.


• Oral sex - the risk of infection is much higher if either sex partner does not know whether he/she is infected, or if the non-infected partner engages in oral sex without knowing whether the other person is infected.


• New sexual partner - if you have a new sexual partner and you can both be tested before sexual intercourse, your risk of infection is almost completely eliminated.


• Regular screening - regular screening for people in high risk groups reduces the risk of transmitting the infection or becoming infected.


• Avoid douching - douching lowers the number of "good bacteria" in the vagina, which raises the risk of infection - not just chlamydial infection but many other types of infection. Douching means using water or a medicated solution to clean the vagina. ACOG (American College of Obstetricians and Gynecologists) recommends against douching.


• Tell people - we can all help reduce the incidence of Chlamydia by telling people about Chlamydia, risks of infection, risk factors, the benefits of regular screening, using condoms, etc. Sexually transmitted infections are more common where ignorance is higher. Ignorance means not knowing enough about a disease, its risk factors, treatment, possible complications, and effective prevention measures.