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Original article
Aptima Trichomonas vaginalis assay elucidates significant underdiagnosis of trichomoniasis among women in Brazil according to an observational study
  1. Mirian Pinheiro Bruni1,
  2. Mariangela Freitas da Silveira2,
  3. Dulce Stauffert2,
  4. Guilherme Lucas de Oliveira Bicca2,
  5. Carolina Caetano dos Santos1,
  6. Nara Amélia da Rosa Farias1,
  7. Daniel Golparian3,
  8. Magnus Unemo3
  1. 1 Post Graduation Program in Parasitology, Biology Institute, Federal University of Pelotas (UFPel), Pelotas, Brazil
  2. 2 Maternal and Child Department, School of Medicine, Federal University of Pelotas (UFPel), Pelotas, Brazil
  3. 3 WHO Collaborating Centre for Gonorrhoea and other STIs, Department of Laboratory Medicine, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
  1. Correspondence to Dr Magnus Unemo, WHO Collaborating Centre for Gonorrhoea and other STIs, Department of Laboratory Medicine, Örebro University Hospital, Örebro SE-701 85, Sweden; magnus.unemo{at}


Objectives Trichomonas vaginalis (TV) infection is the most common non-viral STI globally and can result in adverse pregnancy outcomes and exacerbated HIV acquisition/transmission. Nucleic acid amplification tests (NAATs) are the most sensitive diagnostic tests, with high specificity, but TV NAATs are rarely used in Brazil. We investigated the TV prevalence and compared the performance of the US Food and Drug Association-cleared Aptima TV assay with microscopy (wet mount and Gram-stained) and culture for TV detection in women in Pelotas, Brazil in an observational study.

Methods From August 2015 to December 2016, 499 consecutive asymptomatic and symptomatic sexually active women attending a Gynaecology and Obstetrics Outpatient Clinic were enrolled. Vaginal fluid and swab specimens were collected and wet mount microscopy, Gram-stained microscopy, culture and the Aptima TV assay performed.

Results The median age of enrolled women was 36.5 years (range: 15–77). The majority were white, had a steady sexual partner and low levels of education. The TV detection rate was 4.2%, 2.4%, 1.2% and 0% using the Aptima TV assay, culture, wet mount microscopy and Gram-stained microscopy, respectively. The sensitivity of culture and wet mount microscopy was only 57.1% (95% CI 36.5 to 75.5) and 28.6% (95% CI 13.8 to 50.0), respectively.

Conclusions A 4.2% positivity rate of T. vaginalis was found among women in Pelotas, Brazil and the routine diagnostic test (wet mount microscopy) and culture had low sensitivities. More sensitive diagnostic tests (NAATs) and enhanced testing of symptomatic and asymptomatic at-risk women are crucial to mitigate the transmission of TV infection, TV-associated sequelae and enhanced HIV acquisition and transmission.

  • trichomonas infection
  • trichomoniasis
  • trichomonas vaginalis
  • nucleic acid amplification test (NAAT)
  • aptima
  • wet mount microscopy
  • culture
  • Brazil

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  • Handling editor Professor Catherine A Ison

  • Contributors MPB, MFdS, NAdRF and MU designed the study. MFdS and NAdRF provided an overall coordination of the collection of clinical samples, which were mainly collected by MFdS, DS and GLdOB. MPB, CCdS, DS and DG performed all laboratory work. MPB, NAdRF, MFdS and MU wrote the first draft of manuscript. All authors contributed to the finalisation of the manuscript.

  • Funding This work was supported by grants from the Programa de Apoio a Pós-Graduação (PROAP) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Brasília, DF, Brazil, the Örebro County Council Research Committee and the Foundation for Medical Research at Örebro University Hospital, Örebro, Sweden.

  • Competing interests None declared.

  • Patient consent Not required.

  • Ethics approval Ethics Committee of the Faculty of Medicine, Federal University of Pelotas (Committee Approval number 873.180) and National Commission on Ethics in Research (amendment 1.838.829).

  • Provenance and peer review Not commissioned; externally peer reviewed.