Oral myiasis: Analysis of cases reported in the English literature from 1990 to 2020

Myiasis on the tongue of a patient hospitalized in a psychiatric ward: A case report with a focus on diagnosis and clinical management

INTRODUCTION

Myiasis is a disease caused by the infestation of fly larvae in the skin, which complete part of their life cycle by feeding on host tissues.

OBJECTIVE

To report a rare case of tongue myiasis in a patient admitted to a psychiatric ward, focusing on clinical management.

CASE REPORT

A dependent care and mentally challenged 55 years old male patient was hospitalized in a psychiatric ward. After 42 days, during the intraoral examination, it was noted numerous larvae peeking from inside of a wound on the dorsum of the tongue. The clinical diagnosis of myiasis was rendered. For the treatment, manual removal was performed initially and ivermectin (15 mg), metamizole sodium (500 mg/ml), and chlorhexidine digluconate (0.12%) were prescribed. After one week, larvae were no longer observed, and the wound was completely healed.

CONCLUSION

Myiasis occurrence is uncommon in the mouth, however, its correct diagnosis and treatment are necessary to avoid further damage to patients, especially those who are hospitalized.

Treatment of oral myiasis in a patient with implant-supported fixed prosthesis

Oral myiasis is a rare parasitic disease that requires immediate treatment once diagnosed. However, no standard treatment protocol can be found in the literature. Through a clinical-surgical report, we present the case of an 82-year-old man with lesions extending through the vestibule and alveolar ridge of the maxilla on both sides, in addition to occupying a large part of the palate, with a considerable number of larvae. The patient was initially treated with a single dose of systemic ivermectin (6 mg orally) and topical application of a tampon soaked in ether. The larvae were then surgically removed and debridement of the wound was performed. A crushed tablet of ivermectin 6 mg was applied topically for 2 days, the remaining larvae were again mechanically removed, and the patient received intravenous antimicrobial therapy. Treatment with systemic and topical ivermectin combined with antibiotic therapy and debridement proved to be effective in treating oral myiasis.

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Comparative evaluation of vegetable matter involved lesions with oral parasitic infections in the oral cavity

The current research aims to perform a comparative evaluation of vegetable matter involved lesions with oral parasitic infections found in oral mucosa, presenting histochemical methods to differentiate their microscopic similarities. Eight cases were selected out of a sample of 1.975 reports from a single Oral and Maxillofacial Pathology Service of the author's institution from 2012 to 2019. Specimens were examined by hematoxylin and eosin staining (HE), periodic acid-Schiff (PAS) staining, Gomori-Grocott staining, Ziehl-Neelsen staining, Giemsa, and mucicarmine staining. Microscopic analysis included fluorescence, polarized light, and confocal microscopy. Microscopically, in HE coloration, hookworm eggs showed as eosinophilic. Inflammatory multinucleated giant cells and lymphocytes, were usually related to the nematode eggs, forming an intense inflammatory infiltrate. Biofluorescent properties of eggs and larvae revealed to be sensitive in the detection of parasitic structures contrasting with the inflamed connective tissue. Vegetable presence was confirmed by polarized light microscopy and it was found to be associated with microbial biofilms. Confocal microscopy has showed to be an excellent method for morphotype differentiation of parasitic eggs. Parasitic infection and vegetable matter displayed similarities in the inflammatory response, but the latter can rot and agglomerate biofilms. The microscopic diagnosis of such infections requires the interpretation of challenging morphological features since the parasites are usually sectioned and mixed with an inflammatory reaction. These histochemical approaches proved to be excellent to distinguish both lesions.