Nosocomial myiasis by Cochliomyia hominivorax in Honduras

TRANSACTIONS OFTNE ROYAL SOCIETY OFTROPICAL MEDUNE AND HYGIENE (1993) 87, 199-200

I

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1Short Report 1 Rlosocomial hominivorax

myiasis by Coc~~~omyja in Honduras

Rma Girard de Kaminsky LXreccGn de ~~ves~ig~~~~ Cht~fica, ~at~a~a~ A~tanamo~s ~n~versi~~ of Honduras, Apartado Postal 1587, Tegucigalpa, Honduras

Nosocomial my&is, although rare, is sometimes recorded in deb~itated or comatosepatients. A recent revision of literature reports in the United Statesand Puerto Rico indicated that hospital-acquired myiasis was probably under-reported. It usually occurred during the summer months when fly populations were more dense, and the speciesof flies identified were Cac~Zi~yia macellu~a and f%aenicia sericata, both facultative saprophytes not likelv to invade tissues (SMITH & CLEVENGER.1986: Fox* & RODRIGUEZ-TOR~ENS? 1972; JACOBSO~~’ et al.: 1980; GREENBURG,1984). This report differs in that it documents for the first time 2 casesof human myiasis by

199

C. hominivorax in Honduras, one of which was a nosocomial infestation. The casehistories follow. Case no. 1

A 19 years old woman from rural Honduras (Sulaco, Yoro) with a one year history of vulvar condyloma was admitted for treatment on 1 August 1989 at the Hospital Escuela in Tegucigalpa. Two weeks after admission a nurse reported having seen ‘worms’ in the vulvar condyioma. Examination revealed a giant, foul-smelling condyloma infested with maggots. The patient was alert and co-operative, and complained of unbearable pruritus. Manually, 150 3rd instar larvae were initially removed. The next day, because more maggots were noticed, the patient was brought under general anaethesiaand 100additional larvae were extracted (Figure). The remainder of the patient’s stay in the hospital was uneventful; she was successfully treated for the condyloma and discharged on IO October 1989. All but 12 of the larvae were placed for 5 min in boiling water before fixation in 70% ethanol. Two were cleared in 10% KOH to reveal the morphology of the posterior spiracles and tracheal trunks. Ten larvae were kept in a cage and allowed to complete development at room temperature. After 7 d pupation, 8 adults were recovered and identified as the screw-worm C. kominivorax (by Dr Ronald Cave, Panamerican Agriculture School, El Zamorano, Honduras) using the criteria given by JAMES& HARWOOD(1969). Case no. 2

A second caseof C. hominivorax myiasis was identified in a 22 months old boy from a periurban area, who was admitted to the hospital becauseof fever, epistaxis, fetid, purulent nasal secretions, and nasal maggot expulsion. Physical examination revealed a malnourished patient, with left basal bronchopneumonia and a retropharyngeal abscesswith protrusion of the left palate due to the maggots. Under general anaesthesiaand endotracheal intubation, 161 larvae were removed. The larvae, recognized as 3rd instar, were fixed inadequately in 70% ethanol and autolysed, leaving a transparent exoskeleton. This facilitated recognition, after mounting, of the characteristic posterior spiracles with their depressedstigma1plate on the dorsal surface of the posterior segment, and the sclerotized dark tracheal trunks (JAMES& HARWOOD,1969), although it was not possible to rear adult flies to confirm the identification. Discussion C. hominivorax is well known for invasion and tissue

destruction, causing deep disfiguring wounds and sometimes death (ESSLINGER,19%; MURRAY & TWOMPSON, 1976). Myiasis originating in a hospital is unusual and, when reported, occurred in debilitated or comatose patients. In the Hospital Escuela, however, windows and other openings to the exterior are not screened, permitting free entrance of flies which could have been attracted to the malodorous, uncovered condyloma: the patient was young and neither debilitated nor comatose. A revision of the local literature in the last 30 years disclosed only one report of myiasis due to Dermatobiu hominis (ELVIR, 1974). The statistics department at Hospital Escuela, however, has recorded 73 admissions during 1987-1990 as human myiasis. Three caseswere recognized as due to D. hominis,. but no other was specifically identified. The Mmistry of Natural Resources,with international assistance,has initiated a programme for eradication of C. ~orn~~~~orax (Dr Mario Matamoros, Ministry of Natural Resources, personal communication; SNOW et al., 1985). Figure. A. Giantcondyloma, showingareasof haemorrhage. B. Someof the C. ~~~~~~~orux3rd instar larvae manually removed from the condyioma (boiled5 minin waterand fixed in 70%ethanol).

Acknowledgements

I thankthe PanAmericanAgricultural Schooland Dr Ronald Cavefor the facihtiesofferedand for the identification of the fly

200 species, and Drs Jackeline Alger and Arturo Alvarez for assisting with the patients’ care. References Elvir, C. (1974). Myiasis orbitaria por Dermatobia hominis. Revista Mddica Hondurefia, 42.253-257. Esslinger, J. (1958). Effecis of the screw-worm on guinea-pigs. Journal ofParasitology,

44,201-209.

Fox, I. & Rodriquez-Torrens, R. (1972). Human macellaria myiasis in Puerto Rico. Boletin de la Asociacidn Mkdica de Puerto Rico, 64,53-55.

Greenburg, B. (1984). Two casesof human myiasis caused by Phaenicia sericata (Diptera: Calliphoridae) in Chicago area hospitals.Joumal ofMedical Entomology, 21,615-617. Jacobson, J., Kolts, R., Conti, M. & Burke, J. (1980). Hospital acquired myiasis. InfectionControl, 1,319-320.

1Announcement

Tames.M. & Harwood. R.F. lo&. London: Macn&an. Murrav, F. I. & Thompson, other animals in Trinidad

11969).He&s Medical Entomo’ ’ D. (1976). Mviasis in man and and ‘Tobago (i972-73). Tropical

Agriculture, 53,263-266.

Smith, D. and Clevenger, R. (1986). Nosocomial nasal myiasis. Archives of Pathology and Laboratory Medicine, 110,439-440. Snow, W. J., Whitten, C. J., Salinas, A., Ferrer, J. and Sudlow, W. H. (1985). The screw-worm Cochliomyia hominivorax (Diptera: Calliphoridae), in Central America and proposed plans for its eradication south to Darien gap in Panama.younal ofMedical Entomology, 22,353-360. Received 31 March 1992; publication SJune 1992

revised1 June 1992; accepted for

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