Changing sexually transmitted infection screening protocol will result in improved case finding for trichomonas vaginalis among high-risk female populations.

BACKGROUND: Trichomonas vaginalis is a sexually transmitted infection, which is largely underestimated because of ineffective screening protocols and lack of public health attention.
METHODS: Two studies were conducted to assess the frequency of missed diagnosis of T. vaginalis when using current routine practices for T. vaginalis screening in high-risk female populations. The first study compares the rate of positivity detected using wet preparation microscopy to the number of cases found using polymerase chain reaction (PCR) using residual samples from women attending a public health sexually transmitted disease clinic. The second study compares universal to targeted screening of symptomatic women using PCR on vaginal samples from women screened for sexually transmitted disease at a correctional facility.
RESULTS: In the first study, a 5-fold increased incidence of T. vaginalis infection was detected when PCR was performed instead of wet mount microscopy in a sample of 222 women screened at a sexually transmitted disease clinic. The second study detected a 5-fold increase in cases among a sample of 471 incarcerated women when universal screening was implemented.
CONCLUSIONS: Improving detection of T. vaginalis is critical, given that when left untreated, T. vaginalis increases susceptibility to coinfections including human immunodeficiency virus. Changing screening protocols to use improved diagnostic tools and applying universal screening resulted in increased case finding for T. vaginalis among high-risk women. The prevalence of T. vaginalis coupled with its negative impact on health necessitate greater public health attention is needed in order to reduce incidence rates, improve diagnosis, and to better understand this important, yet underestimated, pathogen.