It is possible for some individuals to contract sexually transmitted diseases (STIs) unexpectedly due to a lack of adequate screening and the presence of asymptomatic infections. Even in a faithful, one-on-one relationship, there are still reasons why STIs can occur.
One of these reasons is pre-existing infection. One of the partners may have been infected before the relationship started, as many STIs do not show symptoms immediately. Some infections, such as genital herpes, HPV, and HIV, can take months or even years to develop symptoms, while others like chlamydia and gonorrhea may cause atypical symptoms that are easily confused with other conditions.
Another reason for contracting an STI is treatment failure. Diseases like syphilis have distinct stages, and if treatment fails at any point during the course of the disease, it can progress invisibly and only show serious symptoms later on. Antibiotic resistance can also cause treatment failure, making it more difficult to treat the disease when it relapses.
Incomplete screening can also result in undetected STIs. There are over 20 different sexually transmitted diseases that require different types of tests for diagnosis. Common tests may only screen for certain diseases while others may be overlooked if the patient is not in a high-risk group. Inaccurate test results can also occur, especially during the incubation period when antibodies have not yet developed.
Asymptomatic infections where individuals have no symptoms can also lead to the spread of STIs. People infected with diseases like chlamydia, gonorrhea, herpes, HIV
