Morphological and Molecular Identification of Emerged Lophomonas blattarum Infection in Mazandaran Province, Northern Iran: First Registry-Based Study.

In the last decade, several cases of bronchopulmonary lophomoniasis (BPL) have been recorded. Little information is available about epidemiological aspects on Lophomonas infection among BPL patients. The present study was aimed to investigate the prevalence of Lophomonas spp. infection in patients who were referred to the Iranian National Registry Center for Lophomoniasis (INRCL), using morphological and molecular tests. We examined patients enrolled in the INRCL from 2017 to 2019 at the Mazandaran University of Medical Sciences, northern Iran. All bronchoalveolar lavage fluid (BALF) and two nasal discharges of the patients were examined by both microscopic and small-subunit ribosomal RNA (SSU rRNA) PCR methods. To confirm the species of Lophomonas, two positive samples were sequenced. In this study, 321 specimens (including 319 BALF and 2 nasal discharges) were microscopically examined. Lophomonas spp. was found in 45(14%) (n = 44 BAL; n = 1 nasal discharge). The mean age of infected patients was 54.9 ± 17.1 years. The following morphological characteristics were observed in both fresh and Papanicolaou-stained smears to identify Lophomonas spp. All microscopically positive specimens were confirmed with genus-specific PCR technique. The obtained sequences were deposited in Gen Bank under the accession numbers (MN243135-36). The BLAST analysis of our two sequences with the only available sequence in the Gen Bank of the Thailand strain of L. blattarum, showed identity of 99–100% and 98.51%, respectively. To the best of our knowledge, this is the first registry-based study regarding lophomoniasis worldwide. According to our study, the conventional PCR test is an available and reliable tool for confirming the Lophomonas parasite in clinical samples. Moreover, the results confirmed that L. blattarum is circulating at least in our region.