British Journal of Oral and Maxillofacial Surgery (2003) 41, 115–116 © 2003 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Science Ltd. All rights reserved. doi:10.1016/S0266-4356(02)00302-9, available online at www.sciencedirect.com SHORT COMMUNICATION Oral myiasis by screwworm Cochliomyia hominivorax R. S. Gomez, * P. F. Perdigão, * F. J. G. S. Pimenta, * A. C. Rios Leite, † J. C. Tanos de Lacerda, ‡ A. L. Custódio Neto § * Department of Oral Surgery and Pathology, School of Dentistry; †Department of Parasitology, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, Belo Horizonte – MG 31270901, Brazil; ‡Odilon Behrens Hospital, Belo Horizonte, Brazil; §Department of Morphology, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, Belo Horizonte – MG 31270901, Brazil SUMMARY. We report a rare case of periodontal myiasis by New World screwworm Cochliomyia hominivorax, an obligatory larval parasite, in a 66-year-old woman. The myiasis occurred in the anterior upper jaw associated with a pre-existent generalised periodontitis. About 40 larvae were removed from the lesion. One week later the periodontal tissues were healing normally and the patient was referred to a periodontist. As all of the larvae were in the last stage, they were probably deposited 5–7 days before. © 2003 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Science Ltd. All rights reserved. INTRODUCTION Myiasis is an infestation of a live vertebrate by dipterous larvae, which at least for a time feed on living or dead host tissue, liquid body substances, or undigested food. 1 The myiasis can be obligatory, when larval flies (three stages) develop in living tissue, or facultative, when maggots feed on decomposing matter or necrotic tissues. Oblig- atory myiasis is more harmful for the host, particularly mammals (including man), in several countries of the Old and New Worlds. 2 Depending on the favoured site of the compulsory larval parasitism, the myiasis can occur in skin – by maggots from families Cuterebridae and Hypo- dermatidae and a few Calliphoridae and Sarcophagidae species – and in cavities – by Gasterophilidae (diges- tive tract). Unusual sites for myiasis include the mouth, nose, eye, lung, ear, anus, and vagina, 2 but periodontal involvement is rare. CASE REPORT A 66-year-old woman was referred to Odilon Behrens Hospital in Belo Horizonte city for evaluation of an oral lesion. The patient was a drunkard. An oral examination we found a large wound associated with the upper incisors which were mobile. The wound contained numerous mag- gots (Fig. 1). The patient had generalised chronic peri- odontitis. Under local anaesthesia the teeth 7, 8, 9, and 10 were extracted for advanced periodontal disease and at least 40 larvae were removed (Fig. 2). One week later, the wounds were healing normally and the patient was re- ferred to the Department of Periodontology at Universi- dade Federal de Minas Gerais (UFMG). The specimens were sent to the Department of Parasitology at UFMG, where microscopy showed that the larvae were third-stage Cochliomyia hominivorax. DISCUSSION Myiasis is caused by members of the Diptera fly fam- ily that lay eggs or larvae on food, necrotic tissue, open wounds, and unbroken skin or mucosa. The classification of myiasis is based on their localisation on the host body (dermal, subdermal, nasopharyngeal, internal organs, and urogenital) or in, parasitological terms, on the type of host–parasite relationship (obligatory, facultative or pseu- domyiasis). Larval flies that show obligatory develop- ment of the three stages in live tissues cause the most morbidity. 2 Some of these dipterans can develop in vari- ous mammalian species, including man. When tissues of the oral cavity are invaded by the parasitic larvae of flies, oral pathologists name this condition oral myiasis. 3,4 Although there are some reports of oral myiasis, the classification of the larvae that causes the infestation has rarely been made. In the present case the larvae showed features char- acteristic of C. hominivorax, of the Callipharidae fam- ily. The New World screwworm C. hominivorax is found 115