Trichomoniasis update

The 2015 STD Treatment Guidelines released by the Centers for Disease Control and Prevention (CDC) in June 2015, include several major updates to the section on trichomoniasis.¹

The new guidelines were developed based on a thorough review of current scientific evidence, said Elissa Meites, MD, MPH, a medical epidemiologist at the CDC, who led development of the section. 

She added, however, that an examination of available literature supports the notion that trichomoniasis is a “neglected” infection about which many important questions remain unanswered. 

Dr Meites is lead author of the published paper that reviews scientific evidence used for the development of the 2015 STD Treatment Guidelines section on trichomoniasis.² She also wrote and coauthored other articles reviewing and discussing trichomoniasis as a neglected infection.^3,4 

As noted in the latter paper, research and control efforts for Trichomonas vaginalis infection traditionally have lagged far behind efforts for other sexually transmitted infections (STIs), even though T. vaginalis infection is the most prevalent non-viral STI in the United States and more common than chlamydia, gonorrhea, and syphilis infections combined.

The authors concluded, “Increased emphasis on detection and treatment of infections is needed to move trichomoniasis out of the neglected category and to provide better care for those most impacted by this parasitic disease.”⁴

As noted in the published paper, poor understanding of its public health impact is one important factor in the low level of attention given to T. vaginalis infection.

Whether trichomoniasis should be a reportable condition was the subject of a recent editorial from the CDC.⁵ As stated in this paper, 7 criteria of public health importance determine whether a condition warrants surveillance-indices of frequency, disparities or inequities, communicability, severity, costs, preventability of complications, and public interest. T. vaginalis infection, however, meets only the first three.

“Further studies are needed to develop the evidence base for T. vaginalis infection to be considered an STI of higher public health priority,” Dr Meites and colleagues concluded. Specific issues  for current and future research include examination of the epidemiology of trichomoniasis among men and women; the true public health burden of symptomatic and asymptomatic T. vaginalis infections; and whether current treatments will be adequate to reduce health disparities and costs associated with trichomoniasis. 

“Trichomoniasis is so common, but people forget about it because it doesn’t often cause problems - and when it does, it is treatable. Also, for a long time, this infection was recognized only in women, but actually it is passed back and forth quite easily between sex partners. New diagnostic tests may make it easier for people who are infected to get tested and treated along with their partners,” Dr Meites said. 

2015 STD Treatment Guidelines updates

Key updates to the trichomoniasis section in the new STD Treatment Guidelines pertain to current epidemiology, guidance on the use of novel diagnostic methods, identification of high-risk groups, and treatment recommendations for HIV-infected patients.¹

As noted in the guidelines, T. vaginalis infection is estimated to affect 3.7 million women and men in the United States, but there are disparities in its prevalence by race/ethnicity and age. T. vaginalis infection affects 13% of black women versus only 1.8% of non-Hispanic white women. In addition, unlike other non-viral STDs, a higher prevalence has been detected in older age groups (eg., >11% in women age ≥40). High prevalence of T. vaginalis infection has also been identified among persons presenting to sexually transmitted disease clinics, particularly symptomatic individuals, and people incarcerated in correctional institutions.

According to the guidelines, decisions about screening might be informed by local epidemiology of T. vaginalis infection; screening might be considered for persons receiving care in high-prevalence settings and for asymptomatic persons at high risk. Routine screening and prompt treatment are recommended at least annually for all women with HIV infection. Testing for T. vaginalis is recommended for those who are symptomatic.

Regarding diagnosis, the 2015 guidelines identify nucleic acid amplification tests (Aptima T. vaginalis assay, Hologic; BD Probe Tec TVQ^x Amplified DNA Assay, BD; and others) and same-day or point-of-care tests (OSOM Trichomonas Rapid Test, Sekisui Diagnostics; Affirm VP III, BD) as newly available methods that can be conducted on a variety of specimens, potentially allowing highly sensitive testing and screening of both women and men at risk for infection.

For treatment of trichomoniasis, single-dose therapy with an appropriate nitroimidazole antibiotic (ie, metronidazole 2 g or tinidazole 2 g) remains the recommended regimen. Based on results of a randomized clinical trial conducted among HIV-infected women, however, the current guidelines recommend that women who are also infected with HIV should be treated with a longer 7-day course of metronidazole 500 mg twice daily.

References

1. Workowski KA, Bolan GA; Centers for Disease Control and Prevention. ‎Sexually Transmitted Diseases Guidelines, 2015. MMWR Recomm Rep. 2015;64(RR-03):1-137. Available at: http://www.cdc.gov/std/tg2015.

2. Meites E, Gaydos CA, Hobbs MM, et al. A review of evidence-based care of symptomatic trichomoniasis and asymptomatic Trichomonas vaginalis infections. Clin Infect Dis. 2015;61(Suppl 8):S837-48.

3. Meites E. Trichomoniasis: the "neglected" sexually transmitted disease.Infect Dis Clin North Am. 2013 Dec;27(4):755-764.

4. Secor WE, Meites E, Starr MC, Workowski KA. Neglected parasitic infections in the United States: trichomoniasis. Am J Trop Med Hyg. 2014;90(5):800-804.

5. Hoots BE, Peterman TA, Torrone EA, Weinstock H, Meites E, Bolan GA. A Trich-y question: should Trichomonas vaginalis infection be reportable? Sex Transm Dis. 2013;40(2):113-116.