Oral colonization by Entamoeba gingivalis and Trichomonas tenax: PCR-based study in health, gingivitis, and periodontitis

The etiology of periodontitis needs further investigation, as is the place of gingivitis in its pathophysiology. A few studies linked the oral colonization by parasites ( Entamoeba gingivalis and Trichomonas tenax ) to the disease and its severity. The aim of this study was to estimate the prevalence of these oral parasites among healthy individuals, gingivitis and periodontitis patients in Jordan. The study was conducted by active enrolment of participants at Jordan University Hospital. The participants answered a questionnaire that included items related to possible risk factors for periodontal disease. Saliva and dental plaque samples were collected. The detection of oral parasites was done using conventional PCR and microscopic examination of wet mounts. The study population comprised a total of 237 individuals divided into three groups: healthy (n=94), gingivitis (n=53), and periodontitis (n=90). PCR results revealed that the overall prevalence of E. gingivalis was 71.7% compared to 12.2% for T. tenax . The periodontal disease group had higher prevalence of E. gingivalis and T. tenax compared to the healthy group (p<0.001). Increasing age was associated with higher prevalence of E. gingivalis (p=0.008) and T. tenax (p=0.019), in the entire study population. The number of cases of colonization detected by microscopic observation was lower for any of the oral parasites, as compared to diagnosis by PCR (40.7% vs. 71.7%, p<0.001 for E. gingivalis and 4.3% vs. 12.2%, p=0.007 for T. tenax ). The higher prevalence of oral parasites among patients with periodontal disease might point to their potential contribution in the disease and its severity. IMPORTANCE Periodontal disease has a high prevalence globally, with adverse effects on the quality of life for affected individuals. Despite the presence of several studies that investigated the role of oral parasites in periodontal disease, reliable conclusions about this matter remained elusive mainly due to utilization of microscopy in parasite detection. The current study provides new insights into the epidemiology and prevalence of the two oral parasites ( Entamoeba gingivalis and Trichomonas tenax ) in patients with various stages of periodontal disease in comparison to healthy adults. In addition, we describe the potential role of oral colonization by parasites as a risk factor for development of periodontal disease and its severity using a molecular-based approach. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was supported by funding from the Deanship of Academic Research at the University of Jordan with ref. No. (126/2019/19) granted on 30th January 2019. The Deanship of Academic Research at the University of Jordan as the funding body, had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study was approved by the School of Medicine and the School of Graduate Studies, University of Jordan. Ethical approval was obtained from the Institutional Review Board (IRB) at JUH (Ref. No. 239/2019). A written and signed informed consent was obtained from all individuals who agreed to participate in the study following full explanation of the study objectives and the procedure of obtaining the samples. In addition, the work was conducted according to the principles of good clinical practice that have their origin in the declaration of Helsinki and all individual data were treated with confidentiality. All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request