Ophthalmomyiasis Externa in Dallas County, Texas

CASE REPORT: OPHTHALMOMYIASIS EXTERNA IN DALLAS COUNTY, TEXAS

ELLEN SIGAUKE, WALTER E. BEEBE, RITA M. GANDER, DOMINICK CAVUOTI, AND PAUL M. SOUTHERN Departments of Pathology and Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; Cornea Associates of Texas, Dallas, Texas

Abstract. Ophthalmomyiasis externa is an uncommon condition in North America. If not recognized and managed accordingly, it can be complicated by the potentially fatal condition ophthalmomyiasis interna. Ophthalmomyiasis externa is mainly caused by the sheep bot fly Oestrus ovis; thus, it is more common in farming communities. We report a case of ophthalmomyiasis externa in a young woman from Dallas County, Texas, who had no known history of contact with farm animals.

INTRODUCTION the anterior segments. The specimen was examined at the Dallas County Hospital District Department of Microbiology. Ophthalmomyiasis externa results from infestation of the A 4.0 × 1.0 mm tan object consistent with fly larva was iden- conjunctiva by the larval form or maggot of flies in the order tified. A more definitive identification was not possible be- Diptera. Other forms of ophthalmomyiasis include ophthal- cause the larva was dead and had not been properly pre- momyiasis interna and orbital ophthalmomyiasis, depending 1,2 served. It was suspected that the patient had eggs on her on the site of infestation. Ophthalmomyiasis interna results hands that were transmitted tothe conjunctivalsac. when the larvae penetrate the globe, and can be visualized in Nomedicationswere prescribed and the patient was dis- the subretinal space and in the vitreous cavity. Orbital oph- charged with instructions to return for re-evaluation at a later thalmomyiasis, the least common of the three conditions, is 1 date. The Infectious Disease service was consulted and con- due to invasion of the orbit. curred with the recommendations. Oestrus ovis, the nasal botfly, is the most common cause of The patient did not return for follow-up examination. A conjunctival ophthalmomyiasis in North America3 and the 4 telephone call to her home confirmed that she remained term ophthalmoestriasis has been proposed. This botfly is a asymptomatic several weeks later. common parasite in the nasal and paranasal cavities of goats and sheep, thus, the name, the sheep nasal botfly. It is common in sheep farming areas, especially in the Mediterranean DISCUSSION countries, southern Africa, and Central America. The organism is rare in the United States, with few reported cases to Human ophthalmomyiasis is rare in North America; how- 3 date. Most cases have been reported from Santa Catalina ever, several cases have been reported. Hennessy and others Island, California, where there is a large indigenous wild goat reported a case of a 16-year-old woman who had been camp- 5 population. A more dangerous form of conjunctival ophthal- ing on Santa Catalina Island, California.6 She had been swim- momyiasis is due to the Russian botfly, Rhinoestrus pur- ming in the Pacific Ocean and hiked through the woods, but pureus, which is found in the nasal passages of equines in denied being struck by a foreign object. Reingold and others 4 southern Europe, Asia Minor, and Africa. The cattle botfly, reported another case of a woman who had an acute onset of Hypoderma bovis, is frequently associated with ophthal- symptoms while vacationing on Santa Catalina Island, but she 6 momyiasis interna. could not recall any stinging sensations or seeing any insects We report a case of ophthalmomyiasis externa in a young nearby.3 Heyde and others reported a similar case of a 28- woman in Dallas County, Texas. year-old man who had been sight-seeing on Santa Catalina Island.5 The patient actually noted a stinging sensation in CASE HISTORY both his eyes after a dive. Human ophthalmomyiasis externa has also been reported in an otherwise healthy, one-month- A 16-year-old woman student from Garland, Texas, with an old infant from urban Atlanta.7 Bosniak and others reported unremarkable medical history, presented to the Cornea As- a case of a 63-year-old diabetic man from New York with sociates of Texas on May 11, 2000 reporting that worms came ophthalmomyiasis in an eyelid reconstruction.8 out of both her eyes as she rubbed her conjunctiva. She had Yoshimoto and Goff reported a case in a 63-year-old man one of the specimens with her. Associated symptoms included in Hawaii who was infected while working on his car.9 They continuous bilateral eye pain with mucoid ocular discharge alsoindicated that there have been othercases in Hawaii. over the five-day period before presentation. She wore con- Other genera of fly larvae have also been reported to be tact lenses. There was no history of previous ocular surgeries, associated with ophthalmomyiasis. Chodosh and others re- and she was not taking any ocular medications. She was in ported a case of nosocomial conjunctival myiasis in a debili- good general health. There was no history of recent travel, tated nursing home resident in Texas.10 The larvae were iden- and no history of exposure to animals other than household tified as Cochliomyia macellaria. Chodosh and Clarridge later pets (specifically, no exposure to sheep, goats, bovines, or reviewed ophthalmomyiasis, and reported other causes in- other livestock). Her family history was significant for diabe- cluded Cochliomyia hominivorax, Chrysomyia bezziana, tes mellitus, cancer, hypertension and arthritis. Wohlfartia magnifica, Dermatobia hominis, Oedemagena On examination she had a visual acuity of 20/20 with spec- tarandi, and Hypoderma spp.11 Many of these infections were tacle correction. There was significant conjunctival follicular in individuals with underlying illnesses, and were frequently reaction in both eyes. No other parasites were noted within the cause of opthalmomyiasis interna. Emborskey and Faden 46 OPHTHALMOMYIASIS EXTERNA IN TEXAS 47 recently reported a case of periorbital swelling in a four year- Received June 24, 2002. Accepted for publication September 25, old boy due to opthalmomyiasis caused by D. hominis.12 In 2002. this instance, the larva was removed surgically from the upper eyelid. Another recent case report from India, involving O. Acknowledgment: We thank Bobbie Wortham for assisting with the preparation of this manuscript. ovis, was somewhat similar to our case in that it was in a 12-year-old boy with conjunctival larvae.13 Although his fa- Authors’ addresses: Ellen Sigauke, Rita M. Gander, Dominick Ca- vuoti, and Paul M. Southern, Department of Pathology, University of ther was a gardener, he had no history of animal contact. Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, First instar larvae, also known as sheep bot, are deposited Dallas, TX 75390-9073. Walter E. Beebe, Cornea Associates of by the adult female O. ovis into the external nares of goats Texas, 7150 Greenville Avenue, Dallas, TX 75231. and sheep and work their way up into the nasal and frontal Reprint requests: Paul M. Southern, Department of Pathology, Uni- sinuses where maturation takes place. The mature larvae versity of Texas Southwestern Medical Center, 5323 Harry Hines drop to the ground and pupate. After three to six weeks, adult Boulevard, Dallas, TX 75390-9073, Telephone: 214-648-3587, Fax: flies emerge from the pupae and their life-span may be up to 214-590-8037, E-mail: [email protected] a month.1,4 The adult fly is approximately 12 mm in length 14 and mainly blackish-brown. Patients with ophthalmomyiasis REFERENCES: externa due to O. ovis typically present with a history of close contact with sheep or goats in early summer to fall.4 The 1. Cameron JA, Shoukrey NM, Al-Garni AA, 1991. Conjunctival symptoms of conjunctival ophthalmomyiasis are similar to ophthalmomyiasis caused by sheep nasal botfly (Oestrus ovis). those of acute catarrhal conjunctivitis.6,15 There may be a Am J Ophthalmol 112: 331–334. history of a foreign object or an insect striking the eye, a few 2. Risco MR, Al-Dosari F, Millar L, 1995. Sheep nasal botfly 1 (Oestrus ovis) larvae infestation of the conjunctiva. Arch Oph- hours before the onset of eye pain and inflammation. The thalmol 113: 529–530. female flies are supposedly capable of ejecting a jet of larvae 3. Reigold WJ, Robin JB, Leipa D, Kondra L, Schanzlin DJ, Smith while in close proximity to the eye. The patient may present RE, 1984. Oestrus ovis opthalmomyiasis externa. Am J Oph- with burning, itching, mobile foreign body sensation, photo- thalmol 97: 7–10. phobia, watery discharge, and eyelid cellulites. A conjunctival 4. Healy MC, Collins RK, Hawkins JA, 1980. Opthalmooestriasis externa. South Med J 73: 1387−1388. pseudomembrane may be present in some cases.6 Follicular 5. Heyde RRS, Seiff SR, Mucia J, 1986. Ophthalmomyiasis externa conjunctivitis and punctate keratopathy are considered char- in California. West J Med 144: 80–81. 3 acteristic. The larva may die in the host giving rise to a 6. Hennessy DJ, Sherrill JW, Binder PS, 1977. External ophthal- permanent nodule, which macroscopically resembles a sty.16 momyiasis caused by Oestrus ovis. Am J Ophthalmol 84: 802– Visualization of the organism is aided by the slit-lamp ex- 804. amination, although the organism usually avoids the beam.15 7. Rao S, Berkowitz FE, Metchock B, 1990. External ophthalmomyiasis in an urban infant. Pediatr Infect Dis J 9: 675–676. The larvae are translucent and small (0.8−1.0 mm), making 17 8. Bosniak SL, Schiller JD, 1990. Ophthalmomyiasis in an eyelid them difficult todetect. Larval identification is aided by the reconstuction. Am J Ophthalmol 109: 101–102. dark mouth claws and the active vermiform movements of its 9. Yoshimoto CA, Goff ML, 1997. Externa ophthalmomyiasis, a body against the congested and edematous conjunctiva.1 disease established in Hawaii. Hawaii Med J 56: 10–12. Double eyelid eversion may aid detection of the larvae in the 10. Chodosh J, Clarridge JE, Matoba A, 1991. Nosocomial conjunc- conjuctival fornix. As many as 50 organisms have been re- tival ophthalmomyiasis with Cochliomyia macellaria. Am J Ophthalmol. 111: 520–521. moved from one eye. Heyde and others reported 50 organ- 11. Chodosh J, Clarridge J, 1992. Ophthalmomyiasis: a review with isms in the right eye and approximately 30 organisms in the special reference to Cochliomyia hominivorax. Clin Infect Dis 5 left eye of a single patient. Treatment of the condition is by 14: 444–449. removal of the larvae. Paraffin oil can be used to stop the 12. Emborskey ME, Faden H, 2002. Ophthalmomyiasis in a child. oxygen supply, thus aiding removal of the larvae. In addition, Pediatr Infect Dis J 21: 82–83. a topical anesthetic can be used to paralyze the larvae, thus 13. Beri S, Langan U, Malik KPS, Bhatnagar SK, 2002. An unusual making their removal by forceps easier.16 Generous amounts cause of conjunctivitis in a child. Trop Doct 32: 183–184. ® 14. Palmer PH, Tingey RE, Holloway BA, 1992. Human ophthal- of Neosporin (Warner Lambert, Morris Plains, NJ) (neomy- momyiasis externa caused by larvae of the sheep nasal bot fly, cin, bacitracin, and polymyxin B) ointment have been used to Oestrus ovis.NZMedJ105: 84–85. 5 facilitate suffocation of the organism. Topical corticosteroids 15. Stulting AA, Meyer H, 1981. External ophthalmomyiasis caused and antibiotics can be used to relieve the inflammation and by Oestrus ovis. S Afr Med J 31: 709–710. prevent bacterial contamination.3 Follow-up examination by 16. Bangsgaard R, Holst B, Krogh E, Heegaard S, 2000. Palpebral an ophthalmologist is recommended to avoid the possible myiasis in a Danish traveler caused by the human bot fly (Der- matobia hominis). Acta Ophthalmol Scand 78: 487–489. complication of ophthalmomyiasis interna.18 17. Harvey JT, 1986. Sheep botfly: ophthalmomyiasis externa. Can J In conclusion, although ophthalmomyiasis externa is an un- Ophthalmol 21: 92–95. common condition in North America, early diagnosis and 18. Torok PG, Davis DL, 1991. Ophthalmomyiasis during Operation management is important in preventing complications. Desert Shield. Mil Med 156: 438–439.