Estudos de freqüência, morfologia e diagnóstico de Entamoeba gingivalis, Gros, 1849

Abstract

Entamoeba gingivalis is found only in its trophozoite form and it is postulated that its main transmission mechanism is through the kiss. E. gingivalis is considered pathogenic by some authors and commensal to others. It does not have a defined role in the installation of disease. To address some of this questions we studied a 100 patients who were seen through the Odontological Hospital from the Universidade Federal de Uberlândia in order to determine its frequency in the buccal cavity. The material were collected using swabs from four different buccal sites and the smears were stained by a modified Papanicolaou technique. The results revealed positivity index of 62%. The affinity of the dye to the food vacuole contents and to the ingested bacterias prevents clear visualisation of the central and peripherical chromatin constituents of the parasite's nucleus. Mouth washes with 3ml of saline from 10 patients, were used to evaluate which parasitological method of diagnosis (fresh, iron-haematoxylin stained, Giemsa and Papanicolaou) gives better visualisation of the parasite. The mouth washes sediment from fresh material revealed 100% of positivity and clear visualisation of the free form and locomotion of the trophozoites. No stained technique of the smear showed adequate visualisation, presenting the nucleus partially covered by the food vacuoles. In stained preparations by toluidine blue ultrastructure analysis of the morphology of parasite can be observed.

First Evidence of Genetic Intraspecific Variability and Occurrence of Entamoeba gingivalis in HIV(+)/AIDS

“…Entamoeba gingivalis is considered a harmless commensal organism in humans and is commonly found in the calculus and bacterial plaques, crevicular fluid, and saliva [6], [7], [8], [9]. There are controversies concerning its pathogenicity because it has been detected in healthy individuals but has also been associated with periodontal disease [10].…”

Usefulness of oral cytopathology in the diagnosis of infectious diseases

“…It is rare to find this organism within lesions of the head and neck region 84 . E. gingivalis is considered to be pathogenic by some authors, 85 and in the oral cavity has been associated with periodontal disease, 86 especially necrotic periodontal disease in HIV‐infected patients 87 . Microscopically, the parasites look like histiocytes, with abundant cytoplasm, a vesicular nucleus, a characteristic karyosome, and pale blue biphasic finely granular cytoplasm containing basophilic fragments of cellular debris.…”

“…E. gingivalis is found only in its trophozoite form and measures between 15 and 60 μm. A heavily inflamed background with numerous neutrophils is present 84–86 . Molecular techniques to detect E. gingivalis can be used in oral scrapings 88 …”

Parasitic infections affecting the oral cavity

“…Furthermore, a study of the risk for periodontal diseases, carried out in 17 different locations in Guatemala on 62 young adolescents, found E. gingivalis in 21% of the children in 11% of the sites investigated (33). Another study, based on 100 randomly selected patients presenting at a Brazilian hospital specialized in odontology, found the prevalence of E. gingivalis to be as high as 62% (16). Thus, apart from an increasing number of reports of positive findings in malnourished people and in patients with immunodeficiency syndromes, E. gingivalis and T. tenax may be more common than originally thought.…”