ORIGINAL PAPER Higher vaginal pH in Trichomonas vaginalis infection with intermediate Nugent score in reproductive-age women—a hospital-based cross-sectional study in Odisha, India Padmalaya Das 1 & Tapoja Swain 1 & Jyoti Ranjan Mohanty 1 & Shalini Sinha 1 & Bijay Padhi 1 & Belen Torondel 2 & Oliver Cumming 2 & Bijaya Panda 3 & Arati Nayak 3 & Pinaki Panigrahi 4 Received: 8 February 2018 /Accepted: 5 June 2018 # Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract A close association between Trichomonas vaginalis (TV) infection and bacterial vaginosis (BV) has been reported. Some other studies have found association is stronger with intermediate Nugent score than BV. Most studies have used wet mount micros- copy, a relatively insensitive method, to detect TV infection. We wanted to study the association of TV infection with BVand with intermediate Nugent score. We undertook a cross-sectional hospital-based study of 1110 non-pregnant women from Odisha state, India, aged between 18 and 45 years, collecting vaginal swabs for diagnosis of BV by Nugent score (NS) criteria and TV by PCR analysis. TV infection was found in 13.3% of women with intermediate Nugent score (NS 4–6) and 13.6% with BV (NS 7–10). Before adjustment, TV infection was associated with BV, intermediate Nugent, vaginal pH ≥ 4.5, and age group between 26 and 35 years. Multivariate analysis confirmed that TV infection was more likely to have raised vaginal pH, either BVor intermediate Nugent. Proportion of TV cases increased sequentially with the increase in Nugent score up to NS 6, after which a decline was observed. Vaginal pH was higher in the TV-infected group than the uninfected group in women with intermediate Nugent, but no difference was noticed in women with BV. TV infection was equally prevalent in women with intermediate Nugent as well as BV. In the intermediate Nugent group women, TV infection was found only when vaginal pH was raised, indicating a crucial role of vaginal pH in determining TV infection. Keywords Bacterial vaginosis . Non-pregnant woman . Nugent score . Trichomonas vaginalis . Vaginal pH Introduction Trichomonas vaginalis (TV) is the most common non-viral sexually transmitted infection (STI) worldwide. World Health Organization estimated the global prevalence of TV at 8.1% for women (World Health Organization 2001) and the total cases globally were 276.4 million (World Health Organization 2008). Majority of these infections occur in resource-limited settings. The prevalence of TV varies greatly across populations, in the USA it is 3.1% among women of reproductive age compared to 11% Tanzania (Sutton et al. 2007; Klinger et al. 2006). Highest prevalence of TV infection in women was found in Papau New Guinea that ranges from 21 to 42.6% (Mgone et al. 2002; Wangnapi et al. 2015). The prevalence of TV infection in India has been found to vary between states from 3.66 to 12.3% (Kaur et al. 2008; Madhivanan et al. 2009; Fule et al. 2012; Sivaranjini et al. 2013). TV infection is associated with vaginitis, cervicitis, urethritis, and other STIs, including HIV (Allsworth et al. 2009; Kissinger and Adamski 2013). Among pregnant wom- en, it is associated with low birth weight, preterm delivery, pelvic inflammatory disease, and premature rupture of mem- branes (Fichorova 2009; Silver et al. 2014). Identified TV risk * Pinaki Panigrahi ppanigrahi@unmc.edu 1 Infection Biology Program, School of Life Sciences, AIPH University, Bhubaneswar, Odisha, India 2 Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK 3 Department of Obstetrics and Gynecology, Capital Hospital, Bhubaneswar, Odisha, India 4 Departments of Epidemiology and Pediatrics, Center for Global Health and Development, College of Public Health, University of Nebraska Medical Center, Omaha, NE, USA Parasitology Research https://doi.org/10.1007/s00436-018-5962-z