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Chlamydiosis

Chlamydiosis is an infectious, sexually transmitted disease (STD) caused by chlamydia (Chlamydia trachomatis). It is one of the most widely spread STD.

Statistical data show that worldwide 100 million people get ill with chlamydiosis annually, and the number of people infected with chlamydias reaches 1milliard. According to the WHO, urogenital chlamydiosis is one of the most common STD. Therefore, it presents a serious problem for modern venereology concerning the creation of maximally effective medicines for treating the so-called non-gonococcal infectious diseases of the genitourinary tract.A wide spread of this infection is, first of all, due to its asymptomatic course.

Chlamydia trachomatisare immobile, gram-negative obligate intracellular microorganisms affecting mostly the genitourinary system. At present, up to 60% of cases of non-gonococcal urethritis are caused by urogenital chlamydiosis. The disease may be latent for a long time due to some unfavorable conditions, such as,the use of antibiotics, overheating, overcooling and cold. During this period of time, chlamydia are able to transform into the so-called L-forms (it looks as if they “hibernate”). This phenomenon contributes to their long intracellular parasitism.

The main routes of transmissioninclude vaginal and anal sex. Newborns can be infected from the sick mother during the delivery process. Contact home transmission is also possible. Women are more susceptible to chlamydiosis than men. The incubation period lasts from 2 weeks to 1 month.

Clinical manifestations

The disease is asymptomatic in 46% of men and 67% of women. If the symptoms develop, they are minimal.

Symptoms of chlamydiosis in women

Chlamydiosis in women is manifested by yellowish mucous or muco-purulent, foul smelling vaginal discharge.  The patient may have dull pains in the external and internal genitalia, itching and burning (during urination as well). Pain in the lower abdomen (in the pelvic area), aggravation of pain before menstruation and spotting between menstrual periods can also be observed.

Symptoms of chlamydiosis in men

Men have different manifestations. In most cases, slight inflammation of the urethra (urethritis) lasting for several months is noted with scanty glassy urethral discharge, itching and burning during urination. The pain is usually dull. It can be felt in the urethra, scrotum, lower back and testicles. Sometimes, clouding of the urine is observed with the presence of pus. In some cases, bloody discharge at the end of urination or at ejaculation can appear. The patient may complain of a general malaise as a result of intoxication.

In a number of cases, chlamydia are able to preserve in the body in the form of isolated micro-colonies on the mucosa (the so-called carriage). In this case, no signs of the organ damage are detected during the clinical, instrumental and laboratory investigations. The patient seems to be clinically healthy, and only after using high-precision methods of investigation (PCR, investigation for culture), it is possible to detect chlamydia. This can be explained by the fact that the immune system tries to suppress chlamydia multiplication.

Diagnosis

Diagnosis of chlamydiosis is complicated, because Chlamydia trachomatis

are intracellular parasites. Therefore, to diagnose chlamydiosis, scrapings from the cells of the affected organ (but not smears) are taken. Sometimes, the use of non-invasive tests is more preferable for patients. Chlamydiosis can also be diagnosed by blood, urine and sperm in men.

To detect chlamydia, the following laboratory tests are used:

Enzyme-linked immunosorbent assay (ELISA)determines the amount of antibodies (IgG, IgA, IgM)to chlamydia in the blood. These antibodies are produced in a response to the infection. They can be detected during the interaction with special preparations containing chlamydial antigens forming a firm complex with antibodies that can be found using different methods.

Blood is also can be used to perform ELISA. This method not only allows determining the causative agent, but also gives information about the stage of the disease(acute or chronic). The first antibodies can be seen on the 10th -20th day of the disease. Then, other antibodies appear, which can indicate chronic chlamydiosis, recontamination or activation of a previous disease that was not properly treated. But the accuracy of this test does not exceed 60% due to the fact that antibodies to Chlamydia trachomatis can be found in healthy people too. The presence of antibodies can be caused by a previously sustained disease (“serologic scar”) and by cross-reactions with respiratory chlamydia. In some cases, false-positive results of the ELISA can occur because ofthe polyclonal activation syndrome.

Polymerase chain reaction (PCR)

            This method gives up to 100% sensitivity and specificity. To perform this test, a small amount of biological material is needed, with the results being available in a day or two. False-positive results can only be observed in the case of incorrect drawing, transportation and treatment of the biological material, as well as in the process of performing the test. Confirmation of the positive result obtained by the PCR is not required. Therefore, this method is considered to be preferable for diagnosing chlamydial infection.

K.A.Karapetova,    doctor-dermatovenerologist