Trichomonas vaginalis prevalence in the United States
Background: Trichomonas vaginalis prevalence is not well characterized and two national studies (NHANES 2001-2004; Ginocchio et al. 2012) provided estimates for women between 3.2% and 8.7%. This may be related to differences in study populations, methodologies, and changes over time. In both studies, prevalence was highest in women age 30+ years. The prevalence of T. vaginalis in men is much less studied. To assess prevalence in both, men and women, we screened samples from individuals (n=6362) of all four CDC STD surveillance regions.
Methods: For women (n=4324), residual vaginal/cervical swab specimens for Chlamydia trachomatis (CT) and Neisseria gonorrhea (NG) screening (age 14-29 years, n=1851) and cervical cytology specimens for HPV screening (age 30+ years, n=2473) were included. Urethral swab and urine specimens from men ages 14-65 years for CT/GC testing (n=2038) were also included. Overall, samples were enrolled from 38 U.S. states over a 8 month period. Testing was performed with the APTIMA Trichomonas vaginalis Assay on the PANTHER System (Hologic, GenProbe).
Results: Overall positivity rates were 3.8% (95% CI 3.2-4.4) in women and 1.3% (0.8-1.9) in men (Figure). Rates differed by age for women (p<0.0001) and by geography for women and men (p<0.0001). Positivity rates were highest in the 20-29 year age group (women: 6.1%, 4.7-7.8; men: 2.0%, 0.9-3.7) and in the South (women: 6.3%, 4.9-7.8; men: 2.9%, 1.6-4.9). Positivity for T. vaginalis correlated with CT/NG detection in women ages 14-29 (odds ratio [OR] 2.5; 1.4-4.2; adjusted OR [aOR] for age 2.7; 1.6-4.7) and for HPV in women ages 30-65 (OR 2.2; 1.2-4.2, aOR for age 2.0; 1.0-3.8). No significant association with CT/NG detection was observed in men (OR 0.9; 0.3-3.1; aOR for age 1.0; 0.3-3.4)
Conclusion: For this cross-sectional study we targeted a routine screening population by using samples submitted for STD screening in women age 14-29, cervical cancer screening age 30-65, and STD screening in men age 14-65. Prevalence estimates in women are similar to those from NHANES 2001-2004 (2.3%-4.1%). In contrast to the two previous studies but similar to other STIs, positivity rates were highest in the 20-29 year age group. The overall prevalence of T. vaginalis in men was almost 3-times lower than in women.
Gen-Probe: Collaborator, Kits supplied for study
K. Kalp, None
T. Lunt, None
R. Schlaberg, Hologic: Grant Investigator and Research Contractor, Grant recipient, Research grant and Research support
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