Human Nasal Myiasis Possibly Associated with Cocaine Abuse

Blow fly (Diptera: Calliphoridae) larvae have been reported previously from human nares in cases of facultative myiasis (James 1947, USDA Misc. Publ. 631; Beckendorf et al. 2002, Arch. Intern. Med. 162: 638 - 40; Daniel et al. 1994, J. Hosp. Infect. 28: 149 - 52; Jacobson et al. 1980, Infect. Control 1: 319 - 20; Magnarelli et al. 1981, Am. J. Trop. Med. Hyg. 30: 894 - 96; Manfrim et al. 2007, Int. Arch. Otorhinolaryngol. 11: 12 - 16; Smith and Clevenger 1986, Arch. Pathol. Laboratory. Med. 110: 439 - 440). These are often hospital-acquired infestations of comatose or incapacitated patients. However, nasal myiasis is uncommon. In a review of 400 articles on myiasis which reported 137 unique cases of U.S.-acquired myiasis, only 3 of those cases involved the nasal passages (Sherman 2000, Arch. Intern. Med. 160: 2004 - 14). The condition apparently affects men and women equally, usually in patients over 50, and mainly those in lower social classes (Sharma et al. 1989, J. Laryngol. Otol. 103: 489 - 91). Nasal ulcers, damage from leprosy, rhinorrhea, atrophic rhinitis, and nasopharyngeal infections may attract ovipositing flies (Manfrim et al. 2007; Sharma et al. 1989; Rao 1929, Indian Med. Gaz. 64: 308 - 82;Thami et al. 1995, J. Dermatol. 22: 348 - 50). Herein, we present a case of nasal myiasis, at first thought to have resulted from a car accident (and subsequent environmental exposure), but later assumed to be associated with cocaine abuse.

Case Report

A male Caucasian in his 20's was involved in a car accident along the Mississippi Gulf Coast during June 2008. The victim was ejected from the vehicle and lay in a ditch, exposed to the elements, for approx. 1 h. He suffered a closed head injury and was eventually admitted to intensive care at a local hospital. A routine urine drug screen ordered on admission was positive for cocaine metabolites and cannabinoids. The next day, upon physical exam, 11 gray-white, living, and motile fly larvae were removed from the patient's right nostril. The larvae were approx. 5 mm in length and 1 mm in diam. They were forwarded to the hospital pathology department which, in turn, submitted them to the Mississippi Department of Health. We identified them as 3^rd instar, calliphorid larvae, most likely Phormia regina (Meigen), based on the size, shape, and juxtaposition of the slit-like orifices on the posterior spiracles, an almost inapparent “button”, and the peritreme incomplete.

To rule out possible screwworm infestation, 3 of the larvae were submitted to the USDA, APHIS, National Veterinary Services Laboratory in Ames, IA, where they were identified as Lucilia cuprina (Shannon). An additional specimen was submitted to the Smithsonian Institution where it was identified as “Calliphoridae – not Lucilia; possibly Phormia regina.” Phormia regina is the most commonly encountered blow fly in Mississippi (Goddard and Lago 1983, J. Georgia Entomol. Soc. 18: 481 - 84).

Because the maggots were 3^rd instar, developmental time requirements precluded infestation in the hospital or at the time of the accident (e.g., only 1 day had passed between the accident and removal of the maggots). Therefore, the patient must have suffered from nasal myiasis prior to the accident, perhaps as a result of cocaine abuse which may have led to midline nasal destructive lesions described previously in cocaine addicts (Shah et al. 2007, Nasal manifestations of systemic disease, Pp. 256 - 63 In Current diagnosis and treatment in otolaryngology [Lawani – ed.], McGraw-Hill, NY). His recovery was uneventful, and he was discharged to a rehabilitation facility 3 wks after the accident.

Interestingly, the larvae removed from this patient were extremely small (5 mm), compared with normal 3^rd instar specimens (9 - 17 mm). This might be due to larval exposure to cocaine, which speeds up larval development. Research has shown that maggots develop more rapidly 36 h after hatching if reared on liver and/or spleen of rabbits previously administered with a lethal dose of cocaine or twice such a dose. Total developmental times required for pupation and adult emergence were shortened correspondingly (Goff et al. 1989. J. Med. Entomol. 26: 91 - 93).