A rare case of oral myiasis in a severely frail older patient| JOURNAL OF GERONTOLOGY AND GERIATRICS

Abstract

Background. Myiasis, derived from the Greek “myia” (fly) and “iasis” (disease), refers to infestation by dipterous larvae. First coined by Hope in 1840 and later defined by Zumpt, myiasis involves larvae feeding on live or necrotic tissues. Oral myiasis, a rare condition first described by Laurence in 1909, typically affects individuals with compromised oral hygiene, necrotic lesions, or systemic debilitation.
Case presentation. We report a case of oral myiasis in a 73-year-old non-ambulatory female with multiple comorbidities. The patient presented with pain and swelling in the maxillary anterior region, accompanied by severe halitosis, poor oral hygiene, and live larvae emerging from necrotic oral tissues. Clinical and entomological examination identified the larvae as Chrysomya bezziana. Necrotic tissue was surgically debrided, mobile teeth extracted, and the patient was followed up after anti helminthic medications. Post-operative care included oral hygiene instruction and follow-up. The patient responded well to the treatment.
Conclusions. Oral myiasis is an uncommon yet serious condition, predominantly affecting debilitated or geriatric patients with poor oral hygiene. Awareness and early intervention are crucial for effective management. Preventive strategies such as routine oral care and regular follow-up are essential, especially in vulnerable populations.

INTRODUCTION

The term myiasis is derived from the Greek words “myia,” meaning “fly,” and “iasis”, meaning “disease”. William Hope first introduced the term in 1840 to describe conditions involving the infestation of animal tissue by fly larvae ¹. Later, Zumpt provided a more detailed definition, characterizing myiasis as the invasion of living humans and other vertebrate animals by dipterous larvae, which feed on the host’s tissue – whether living or dead – as well as bodily fluids or ingested material, for at least part of their development ².

Myiasis is especially prevalent among rural communities that reside near livestock, where close contact with animals increases exposure to flies. A specific form, oral myiasis, was initially reported by Laurence in 1909 ³. This condition often arises in individuals with contributing factors such as poor oral hygiene, dental extraction wounds, persistent mouth opening due to malocclusion, or underlying mental health conditions. These factors create an environment conducive to attraction of flies and oviposition.

Myiasis is categorized into primary and secondary forms. Primary myiasis, typically seen in livestock, occurs when larvae feed on living tissue – a condition rarely observed in humans. In contrast, secondary myiasis is more common in human patients, particularly those with necrotic or ulcerative lesions, as it involves larvae feeding on dead or necrotic tissue ⁴.

One notable species responsible for causing wound myiasis is Chrysomya bezziana, also known as the old-world screw-worm fly. This species is widely found across regions including India, the Arabian Peninsula, Southeast Asia, and the Pacific islands, and it affects both humans and animals such as sheep ¹.

This paper presents a case of oral myiasis in a non-ambulatory geriatric female with multiple comorbidities and poor oral hygiene. The entomological aspects of the larvae and its identification have also been discussed.

CASE REPORT

A 73-year-old female presented to the tertiary care center with pain and swelling in the maxillary anterior region of 3 days duration. Patient was apparently normal before 3 days after which she developed the swelling on the anterior upper jaw. The swelling was sudden in onset and gradually progressed to its present size. The swelling was associated with halitosis. She gave history of pain which was of pricking type radiating to the upper half of the face. Patient had a history of hypertension and diabetes mellitus for 10 years and was under medication. There was a history of cerebrovascular accident 10 years back and paralysis of the right side of the body. Patient was under antiplatelet drugs for the same. Patient was non ambulatory for the past 10 years and was on nasogastric tube feeding. The patient, who was bedridden and receiving home-based care, reported to the tertiary care hospital for evaluation and management.

The patient was categorized as very severely frail using the clinical frailty scale (CFS) and the patient was dependent on caregivers for all basic activities of daily living. The Katz index of independence in activities of daily living was 0, indicating that the patient was highly dependent on others. Extra oral examination revealed a single diffuse swelling measuring 5 × 4 cm involving the upper lip and the surrounding structures. Skin overlying the swelling appeared normal. On palpation, the inspectory findings were confirmed and there was no local rise in temperature. The swelling was firm and tender. There was no numbness or paresthesia in relation to the swelling. Intraoral examination revealed diffuse necrosis of soft tissues in labial vestibule in relation to teeth 11, 12, 13, 14, 21, 22, and 23. The anterior part of the hard palate showed necrosis and the mucosa covering it was completely detached exposing the underlying bone. A sinus opening was seen present on the mucosal surface of the upper lip in relation to tooth 11. The patient had poor oral hygiene and grade III mobility of tooth 11. Mouth breathing, severe halitosis and periodontal disease were also noticed. (Fig. 1A) Live grayish white larvae were seen crawling through the opening of the sinus. Necrotic slough was present surrounding the labial vestibule. The area was soft and tender on palpation. Many live maggots were seen emerging from a sinus in the hard palate.

Necrotic slough was mechanically debrided under local anesthesia (2% lignocaine), and multiple live larvae were extracted after asphyxiation with oil of turpentine (Fig. 1B).

The live larvae were removed with tissue forceps and were sent to the Microbiology Department of Madras Veterinary College for identification. The maggots were 10-15 mm long, segmented, whitish and without obvious body processes. The anterior spiracles had five branches and posterior spiracles had open peritreme with three longitudinal sigmatic slits without button. There were also compact spurs surrounding each segment of the body. The larvae were identified as Chrysomya bezziana based on morphology of the body, posterior spiracles, and cephalopharyngeal skeleton under dissecting, light, and stereomicroscopy (Fig. 1C-G). A diagnosis of oral myiasis was confirmed. Necrotic tissue was surgically debrided, mobile teeth extracted, and the patient was followed up after anti helminthic medications. She was also given home care oral hygiene instructions.

DISCUSSION

Oral myiasis is a rare pathology and is associated with poor oral hygiene, alcoholism, senility, suppurating lesions, and severe halitosis ⁵. It arises from invasion of body tissues or cavities of living animals by maggots or larvae of certain dipteran flies. The predisposing factors could be diabetes mellitus, psychiatric illness with impaired manual dexterity, poor oral hygiene, open wounds due to maxillofacial trauma or patients who are senile, mouth breathers or hemiplegic. The flies attracted towards the foul smell of necrotic tissues lay eggs on the necrotic tissue and obtain nutrition from the surrounding tissues ⁶. The pathogenicity of larvae arises from the secretion of toxins, which induce inflammation and hinder the healing process ⁷.

In the present case the bedridden status of the patient, poor oral hygiene, the comorbidities, senility and nasogastric feeding were all predisposing factors to the development of oral myiasis. The impaired self-care ability, reduced awareness and limited communication skills may have led to the late presentation to the hospital.

The treatment modality for myiasis comprises local and systemic measures. Local measures consist of topical application of turpentine, mineral oil, ether, chloroform, ethyl chloride, mercuric chloride, creosote, saline, phenol, calomel, olive oil, iodoform, or other such comparable solvents as advocated in the literature ⁸. These local measures irritate the maggots causing larval asphyxia and force them out of the deeply burrowed cavitations. Topical application of placentrex aids in granulation ⁹. Systemic treatment includes broad-spectrum antibiotics, especially when the wound is secondarily infected and administration of anti helminthic medications like ivermectin ¹⁰. In the present patient, treatment began with debridement using oil of turpentine. This was followed by copious irrigation with normal saline, povidone-iodine and hydrogen peroxide. Mechanical removal of maggots was then performed. The patient was also given anthelminthics and systemic antibiotic coverage. The patient was managed by a team of oral medicine physicians and oral and maxillofacial surgeons at the tertiary care hospital.

Oral myiasis can be prevented by following proper wound care and good oral hygiene measures like regular oral care, use of chlorhexidine mouth rinses and routine follow up of non-ambulatory patients. Dry gauze, or gauze soaked in normal saline, and toothbrush should be used to clean mouth and tongue ^11,12. The caregivers should routinely assist and perform the oral hygiene practices to maintain good oral health, especially for older patients as debility and frailty can interfere with a patient’s ability to self-manage their oral care ¹³.

CONCLUSIONS

Human cases of C. bezziana infestation in the oral cavity are rare. Oral physicians who cater to geriatric patients should be aware of the possibility of Chrysomya bezziana infestation to be able to make a prompt diagnosis and provide appropriate management to prevent morbidity and improve the quality of life of the patient. Oral health professionals should also be aware of the palliative care measures for the management of the same.

Acknowledgements

We acknowledge the department of Parasitology, Madras Veterinary College for the entomological identification of the organism.

Conflict of interest statement

The authors declare no conflict of interest.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Author contributions

JS, AM: conceptualization, writing-original draft preparation; AM: writing-review and editing.

Ethical consideration

The research was conducted ethically, with all study procedures being performed in accordance with the requirements of the World Medical Association’s Declaration of Helsinki. Written informed consent was obtained from each participant/patient for study participation and data publication. The data and image used in this study were anonymized before its use.

History

Received: June 24, 2025

Accepted: August 8, 2025

Figures and tables

Figure 1.A) clinical intraoral image; B) extracted live larvae; Larvae as seen under C) dissecting microscopy; D,E) light microscopy; F,G) stereomicroscopy.

References

1. Hope FW. On insects and their larvae occasionally found in the human body. Trans R Entomol Soc Lond. 1840; 2:256-271.
2. Zumpt F. Myiasis in man and animals in the Old World. Butterworths: London; 1965.
3. Zachariah S, Sehgal S, Dixit U. Oral myiasis: a case report. Spec Care Dentist. 2014;34. DOI
4. Shinohara EH, Martini MZ, Oliveira Neto HG. Oral myiasis treated with ivermectin: acase report. Braz Dent J. 2004; 15:79-81.
5. Abdo EN, Sette-Dias AC, Comunian CR. Oral myiasis: a case report. Med Oral Patol Oral Cir Bucal. 2006; 11:E130-E131.
6. Sadaksharam J, Manoharan P, Rubinibala Chrysomya bezziana associated oral myiasis – a case report. Clin Dent. 2019; 13:10-14.
7. Punhani N, Daniel MJ, Srinivasan R. Oral myiasis – a case report with clinical, radiographic and entomological findings from Puducherry Union Territory, Southern India. J Indian Acad Oral Med Radiol. 2009; 21:187-189.
8. Saravanan T, Mohan MA, Thinakaran M. Oral myiasis. Indian J Palliat Care. 2015; 2:92-94. DOI
9. Shukla AD, Kamath AT, Kudva A. Our experience in the management of traumatic wound myiasis: report of 3 cases and review of the literature. Case Rep Dent. 2016; 2016:7030925. DOI
10. Patel BC, Ostwal S, Sanghavi PR. Management of malignant wound myiasis with ivermectin, albendazole, and clindamycin (triple therapy) in advanced head-and-neck cancer patients: a prospective observational study. Indian J Palliat Care. 2018; 24:459-464. DOI
11. Morandi B, Duque TG, Amorim VCP. Improving oral hygiene for edentulous bedridden patients. MOJ Gerontol Ger. 2018; 3:245-247. DOI
12. Sadaksharam J, Kuduva Ramesh SS. Oral health status and dental treatment needs of geriatric patients in tertiary dental care hospital: a retrospective study. Quintessence Int. 2020; 22:2272.
13. Salamone K, Yacoub E, Mahoney AM. Oral care of hospitalised older patients in the acute medical setting. Nurs Res Pract. 2013; 2013:827670. DOI