Chlamydia Infections

While curable, chlamydia infections have spread globally with considerable impact on public health. The most significant global health impact of chlamydia may be in the evidence suggesting that treatable bacterial sexually transmitted infections such as chlamydia and gonorrhea facilitate heterosexual transmission of human immunodeficiency virus (HIV). There are several types of chlamydia bacteria, but the types with greatest impact on public health are Chlamydia trachomatis and Chlamydia pneumoniae.

Transmission of Chlamydia trachomatis infections occurs through oral, vaginal, or anal contact with an infected person. Women may be at higher risk of infection because certain cells in the female cervix are very susceptible to this infection. Chlamydia infections may be completely asymptomatic in many people. This lack of symptoms or signs to prompt medical attention means that unaware carriers can easily transmit chlamydia infection.

Chlamydia trachomatis also causes trachoma, a severe chronic inflammatory eye disease that is a leading cause of preventable blindness worldwide, and lymphogranuloma venereum, a sexually transmitted infection affecting lymph nodes in the pelvis.

Women with symptoms of chlamydia infection in the cervix may experience pelvic pain, abnormal vaginal discharge, or pain with sexual activity. Men with chlamydia infection of the penis may have abnormal discharge from the penis or pain with urination.

In developed countries, treatment of suspected or diagnosed chlamydia infection is typically with an antibiotic, usually doxycycline or azithromycin. Many areas of the developing world diagnose and treat people for chlamydia infections in the context of World Health Organization guidelines for syndromic management for sexually transmitted infections.

In women, chlamydia infection of the cervix may lead to pelvic inflammatory disease (PID), which usually involves infection of the fallopian tubes. PID can cause tubal scars and blockages that may prevent fertilization of an egg. Scarring associated with PID appears to be one of the major causes of infertility in the world. In addition, scarring may lead to pregnancy implantation in the fallopian tube (ectopic pregnancy). In men, chlamydia may spread to the epididymis, causing inflammation of this reproductive area (epididymitis), and leading to testicular pain, swelling, and infertility in some cases. It is possible for a pregnant woman to pass chlamydia infection to a baby, leading to eye infection or pneumonia.

Condom use reduces the risk of sexual transmission of chlamydia infection. Eradication strategies vary in different [Page 405]areas of the world. Some screening and treatment strategies have focused on screening people who present to their healthcare provider for routine care, while others focus on approaching and screening categories of individuals at highest risk of carrying infection.

Chlamydia pneumoniae causes respiratory infection in humans, commonly children. Manifestations of infection may include pneumonia, sore throat, and laryngitis, among others. Like infections with Chlamydia trachomatis, Chlamydia pneumoniae infections often have no or mild symptoms. Transmission occurs through passing infected respiratory tract secretions. It is difficult to characterize the global impact of these infections due to problems in diagnosis and distinguishing it from other types of respiratory infection.

Chlamydia psittaci rarely causes infection in humans. Symptoms may include fever, chills, headache, muscle aches, and cough. Infection occurs through breathing in secretions from infected, often asymptomatic, birds, usually pet birds and poultry.

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