A retrospective study by G. Bezold et al. (USA), was to determine the frequency of detection of the agents responsible for sexually transmitted infections (STIs) in the absence of clinical symptoms in the semen of men suffering from infertility, and to establish a relationship between infection by these pathogens and changes in the characteristics of sperm. The work included the results of a study on the semen of 241 infertility patients. In addition to studying the standard characteristics of sperm and determining markers for the functional status of the testes and their appendages, the DNA of STI pathogens and a number of other infections have been detected in semen, such as than human papillomavirus, cytomegalovirus, herpes simplex virus, human herpesvirus type 6, Epstein-Barr virus, hepatitis virus. B and Chlamydia trachomatis.

According to the results obtained, 132 (54.8%) patients had leukocytospermia. STI pathogen DNA was detected in 45 samples (18.7%) with the following frequency for various pathogens: cytomegalovirus - 8.7%, human papillomavirus - 4.5%, human herpesvirus type 3 - 3 , 7%, herpes simplex virus - 3.7%, C. trachomatis - 2.5%, Epstein-Barr virus - 0.4%. At the same time, there was no significant difference in the frequency of infection with these pathogens in and without leukocytospermia patients.

The identification of the DNA of STI pathogens in semen was accompanied by a decrease in the number of sperm, their mobility and their concentration in neutral α-glucosidase, while the presence of leukocytospermia accompanied by a decrease in the total number of sperm, the percentage of normal sperm and the concentration of fructose in the sperm. A decrease in the concentration of neutral α-glucosidase, which is a marker for the function of the appendages of the testes, indicates damage to the appendages in patients infected with STI pathogens. At the same time, the appendages of the testes play an important role in the maturation of sperm, and it is their defeat that can cause the described change in sperm motility.

The relatively high frequency of DNA detection of STI pathogens in the semen of men with infertility, accompanied by a deterioration in its characteristics, allowed the authors to conclude that there is a relationship between the infection asymptomatic to STIs and the development of infertility.