mans, sented External ment. fly, Introduction indicated of Waianae Waianae, Cedric Requests Waianae, * 86-260 University Honolulu, the reactions invasions fly, ago tissues. leads this As is into involved, tions. a to influence nonetheless is Waianae Department case Myiasis Internal the invaded.2 elicit the a Oestrus disease, as larvae External internal M. the Fardngton consequence, Coast term to of for but Hawaii Hawaii Hawaii Yoshimoto, of 1925, Coast along inhabited External Hawaii, individual ophthalmomyiasis, rephnts external types serious of human may and depending by Comprehensive ophthalmomyiasis in may Entomology 96792 Comprehensive for of Highway ovis and its is its previously Manoa with only to: MD, even rarely so myiasis flies manifestations, of broadest range external ophthalmomyiasis contact L., MPH ophthalmomyiasis complications striking Hawaiian the a clothing case many death.’ few (order is Health cause upon fly’s Health from of characteristically reports other published types, with sense Center health the a life Center the Various severe condition Diptera). usually worn, islands, asymptomatic cycle, eye is flies, Hawaiian behavior management, according refers in a care

due Cedric

Established relatively or

Ophthalmomyiasis, the complications. other and is reports. caused clinical sites was its providers to to reported and that medical The chance. adnexae, cases of the destruction reported a on cultural to its

M. the is consequences benign whether rare infestation features, by infestations A a or occurrence more have particular more human literature.

Yoshimoto, typical the potential may Ophthalmomyiasis disorder and in HAWAII It practices sheep been disorder occurs Hawaii frequently, common the be of and is host case of unaware MEOtCAL subdivided globe intraocular published. compi species continues to Although and nasal manage tissue of on may as is severe which in often itself most such long than pre JOURNAL,

MD, ica but hu bot by be of of 10

MPH*, illustrative days bulbar ered tion traversing he “thud” residential comfort swelling and something and larvae moistened be not inologist, VOL A The On reported the

in 56, appreciably the tearing of 63-year-old in later, the JANUARY man first were conjunctiva, in proparacaine this sensation

M. following as of his who the the instar section cotton-tipped sought moving, considerable Hawaii fashion. of the skeleton. Fig. ing submitted the left Lee 1997 bulbar the patient discovered Case anterior eyelids, 1.—First slow eye larvae (or man of medical affected of

Goff, day, and but a and stage) Magnification and hydrochloride Waianae larval moving reported was to segments could the numerous were instar marked thereafter palpebral irritation one applicator.

PhD** attention. and of eye. patient working movements, of

A Oestrus larva removed not foreign (island removed no His the lacrimation, 125X. and catch of further larvae experienced conjunctivae. was of son authors 0.5% At

Disease About the on Oestrus cephalopharyngeal of ovis body. re-examined the examined with it. eye, a one Oahu) about it irritation ophthalmic car L. emergency improved (M.L.G.) 11 Examination additional ovis slight (see mild the near a larvae when 1 Although burning mm show Figures aid the injection visual in his by he long, and the the eye were of solution department, an larva. house felt sensation a patient’s blurring, eye. revealed found ophthal 1 and instilla rapidly and lightly recov a of light Two The in saw did the 2). to a reported in Hawaii. However there are no reports of their causing human infestation8 here. Hawaii also harbors fly species which can penetrate tissue readily, potentially causing internal ophthalmomyiasis. These include H,>po derma bovis L. andH. lineatuni Villers. Again, we are not aware of reports of ophthalmomyiasis caused8 by these species in this state. Geographic Distribution External ophthalmomyiasis due to the larvae of 0. ovis has been reported from many parts of the world. It is particularly common in the Near East and the Mediterranean 26basin. Among the Berbers ,’ of547North Africa, the condition is sufficiently prominent that “.‘ 489 it has a specific name, “thimni It is ” also’found in 22Russia, south 23Asia, east 24Asia, southern 25Africa,’ and South 26America. Exter nal ophthalmomyiasis is occasionally3 reported from northern Eu rope,Australia, New 29Zealand,’ and Canada. It may be imported into2728 a presumably non-endemic area by°3 infested travelers. Within the United States, this disorder has been3 reported most frequently from Santa Catalina Island off the coast’ of southern California. It is also known among sheepherders on the Navaho3233343536 Reservation (OH. McKinley, personal communication). Individual cases have been reported from at least twelve other states. Human infestation with 0. ovis has previously been described in Hawaii’ at least four times. One case was reported from Honolulu on the island of Oahu in 1925, three confirmed and three unconfirmed cases from Puako on the island of Hawaii in I956’’ two cases from North Kona on the island of Hawaii in 1983,0 and one case was acquired on the island of Maui and identified in Canada in 1985.’ An investigation into the occurrence of external ophthalmomyiasis Entomologic in Hawaii is in progress and has located more than 20 additional Aspects cases from the islands of Niihau (D. Jamieson, personal communi Oestrus ovis L., the sheep nasal bot fly, is the most common cause cation), Kauai, Oahu, Maui, Lanai, and Hawaii, with positive of human external ophthalrnomyiasis worldwide. is This insect a identification of 0. ovis larvae in several of the cases (unpublished well-known parasite of sheep, goats, and occasionally other ani observations). mals. While in flight, it is able to deposit its living larvae near their nostrils, an event which evokes considerable annoyance and some Clinical Features times causes the animals to fall to their deaths while attempting to A human victim may or may not feel the strike of the adult female flee (oistros = gadfly, sting, hence frenzy). The first instar larvae fly as she deposits larvae. The usual symptoms of infestation include migrate into the nasal cavities and sinuses, feed upon mucous a moving foreign body sensation, itching, burning, and lacrima secretions, and ultimately develop into third instar larvae over a Marginal corneal ulcerations may occur, producing pain period of eight to ten months.’ When 2035tion.’ mature, they drop or are and9 photophobia. The patient or a companion may remove some sneezed out onto the ground where they pupate. Under Hawaiian or’ all of the larvae. The illness is generally self-limited, lasting conditions, they hatch into adult flies three to six weeks later. The no more than about 10 days without treatment.2035 These 2 larvae have adult does not feed during its lifespan of about four weeks. If ° not been known to develop beyond the first instar in human humans are attacked, of larval the sites deposition are usually the conjunctivae. less ’ eyes, and frequently the ears, nose, or throat. Humans are 45 Upon presentation to medical care, examination may reveal accidental hosts, in whom the larvae generally do not develop lacrimation, conjunctival injection, swelling the lids, beyond the first instar. of and possi bly a punctate keratitis or corneal ulceration.’ Careful examina 0. ovis is now found in all sheep-rearing parts of the world. It was 6 tion with a slit lamp or other magnification will reveal the motile probably introduced to Hawaii along with sheep in the latter part of first instar larvae, about 1 mm in 72 length, translucent white in color the eighteenth century, was first recorded by Grimshaw ° from with anterior black hooks connected’ to the remainder of the specimens collected from sheep on Kauai in 1896, and is currently cephalopharyngeal skeleton, and rows of spines between the 11 found wherever these animals are present. Despite scanty records, body segments (see Figure 1). The examiner should take care to it is also known from domestic or feral8 goats, Capra hircus, which ’° evert or doubly evert the lids to facilitate the search, since the are present on most of the inhabited Hawaiian islands.”9 0. ovis larvae actively avoid the light by crawling into 2the sulci. larvae have ° recently been identified in feral goats from the Waianae It is possible to demonstrate serum antibody to the three larval Mountains of Oahu (unpublished observations). instars of 0. ovis in sheep and goats, but these tests are not Less common causes of conjunctival myiasis include the horse 39 commercially available for testing humans, nor are they necessary nasal bot fly, Rhinoestrus purpureus and the moose for clinical management. (elk) throatbotfly, Cephenemyia ulrichii Brauer,’ neither of which is present in the Hawaiian Islands. The 5horse bot fly genus Gas terophilus may cause a subconjunctival infestation,’ and both Gasterophilus intestinalis De Geer and G.6 nasalis L. have been C’o,,tinuedon NextPage

HAWAIIMEDICALJOURNAL, VOL 56, JANUARY 1997 11 Management The larvae should be mechanically removed, either by irrigation development to the third instar over about six weeks in the nasal and with a suitable solution or with jeweler’s forceps, a lightly moist sinus cavities of a patient infected with the human immunodefi ened small cotton bud, or other similar aid. Since the larvae are ciency (HIV) 50virus. There is also a recorded case of a larva actively motile, avoid the light, and may cling to tissue by means of negotiating the Eustachian tube to reach the middle 4ear. These their hooks, removal may be facilitated by immobilizing them with migratory complications of external ophthalmomyiasis may simu cocaine, lidocaine, or pilocarpine drops. Cocaine (4% to 5% solu late direct larval deposition into the nasal cavity (or mouth or ear) tion) is a very effective means of paralyzing the ]arvae,° but is often by the initial fly 45strike. unavailable in medical offices in the United States. Lidocaine, usually available in the form of a solution for injection, has also been Conclusions 40advocated. Pilocarpine 1%ophthalmic solution, commonly avail External ophthalmomyiasis, usually caused by the first instar able as a treatment for glaucoma, slows larval movement in vitro larvaeof the sheep nasal bot fly Oestrus ovis L., is generally a benign within about 5 minutes, although it may be less effective in vivo due (but annoying) disorder in humans, producing a self-limited para to dilution with tears (P. Bjorkman, personal communication). sitic conjunctivitis. It is well known in certain geographic areas, Pilocarpine 4% ophthalmic solution may be more effective, but our particularly the Near East and Mediterranean basin, but is uncom experience with it is limited. mon in theUnited States. Increased scrutiny in the Hawaiian Islands As many as 77 larvae have been recovered from a human eye at has revealed that it occurs much more frequently than previously one 4time, although a smaller number is more common. Removal reported. Greater awareness of this disease may facilitate its diag may’require more than one session due to fatigue of the patient and nosis, management, and the prevention of complications. Studies the operator. If the conjunctiva or cornea is significantly disrupted, are in progress to determine its distribution in Hawaii, the animal consideration should be given to tetanus immunization and antimi reservoirs of 0. ovis, and the potential for controlling or preventing crobial prophylaxis. infestation in animals and humans. Submission of the recovered larvae to an experienced entomolo gist for positive identification is recommended. The reason is that Acknowledgements the treating clinician should be alerted in the event that the infesta We thank Pelle Bjorkman, MD, Katherine Marshall, DVM, tion involves a fly such as Hypoderma sp., whose larvae may easily Stanton Cope, PhD, George Plechaty, MD, Tyrie L. Jenkins, MD, penetrate the eye, with potentially devastating consequences. The Leslie Poon, OD, Kimberly Crunkleton, MPH, Steven Bradley, larvae may be preserved in 35% isopropyl alcohol (half-strength MD, and Dean Jamieson for their interest and assistance. rubbing alcohol) or 70% ethyl alcohol. Re-examination of the patient on the following day is strongly References York: advised, because initial treatment often fails to detect all of the 1 HarwoodRF,James MT.EntomologyinHumanandAnimalHealth.7thed. New Macmillan; 1979:296-318.

nearly transparent larvae hiding deep in the 1 2042sulci. 2. BehrC.Uberdieophthalmomyiasisinternaundeutema.KImMonatsblAugenheilkd.920;64:161-180. Symptoms and signs generally resolve within several days after 3. HermsWB.Ophthalmomyiasisin man due to Cephalomyia(Oestws) ovis (Linn.).J Parasitol. ’ 1925;12:54-56. complete removal of the larvae. Persisting symptoms shouldprompt 4. PampiglioneS.lndagineepidemiologicasullamiasicongiuntivaleumanedaOestrusovisinItalia.Nota further evaluation for remaining larvae or for complications. 1:InchiestaIraimediciitaliani.Nuoviannalidgiene a microbiologia.1958;9:242-263. 5. Al-DabaghM,Al-MuttiN,ShatiqM,Al-RawasAY,Al-SaffarS. AsecondrecordfromIraqofhuman

myiasiscausedbylarvaeofthesheepbotflyOestrueovisL.AnnTropMedParasitoL1980;74:73-77. Complications 6. ZumptF.MyiasisinManandAnimalsintheOldWorld.London:Butterworths;1965:175-179. Although external ophthalmomyiasis caused by 0. ovis is virtu 7. GrimshawPH.FaunaHawaiiensis19013:1-77. ally always self-limited, serious complications are possible. 8. HardyDE. Insects of Hawaii.Vol. 14. Diptera:CyclorrhaphaIV,Series Schizophora,Section 2035 Calypteratae.Honolulu:UniversityPressofHawaii;1981:458-470. Clinicians have observed marginal corneal ulcerations; cornea! 9. FullawayDT.OestrusovisLine.[note].ProcHawEntomolSoc.1924;5:365. abrasions, sometimes linear, suggesting injury by the adult fly in the 10. KomatsuGH.Humanmyiasison Hawaii]note[.ProcHawEntomolSoc.1983;24:188. 2 11. TomichP0. MammalsinHawaii.2nded. Honolulu:BishopMuseumPress; 1986:150-156. course of striking the small conjunctival hemorrhages;’ and 25eye; ° 12. James MT.TheAlesthatcause MyiasisinMan.Washington(DC>:USGovernmentPrintingOffice; punctate keratitis.’ These superficial injuries may be managed by 1947Sep.USDAMiscellaneousPublicationNo.631. conventional means, with a topical antibiotic and4 close follow-up. 13. ZumptF.Ophthalmomyiasisinman,withSpecialreferencetothesituationinsouthernAfrica.SAfrMed 4 1 J. 963;37:425-428. Schenck reported one case probably caused by 0. ovis in which 14. CameronJA,ShoukreyNM,Al-GarniAA.ConjunctivalophthalmomyiasiscausedbytheSheepnasal in:Am larvae had penetrated the bulbar conjunctiva. The most severe boltly (Oestrusovis)[see comments[.AmJ OphthalmoL1991;112:331-334.Comment J 43 Ophlhalmol.1992:113:222. complication occurred in a case seen by Rakusin in South Africa. 15. MikkolaK,SilvennoinenJ, HackmanW.Hirvennenasaivartajanaiheuttamaihmisenoftalmomyiaasi Larval 0. ovis penetrated the globe, with resulting optic neuritis, [Ophthalmomyiasiscaused by the elk throatbot fly(Cephenemyiaulrichi,)in man[. Duodecim. panuveitis, optic atrophy, and visual 44loss. Finally, larvae of certain 1982;98:1022-1025. species regularly penetrate tissues, and after initial 16. MedownickM,Finkelstein6,LazarusM,WeinerJM.Humanexternalophthalmomyiasiscausedbythe other of flies horsebotflylarva(Gasterophilusspp.).AustNZJ Ophthalmol.1985;13:387-390. deposition around the conjunctiva or ocular adnexae, may proceed 17. AmrZS,ArnrBA,Abo-ShohadaMN.OphthatmomyiasisextemacausedbyOestrusovisL.intheAjioun to damage the 645globe.’ Should internal ophthalrnomyiasis be area otnorthernJordan.AnnTropMedParasitol.1993;87:259-262. 18. DarMS,BenAmerM,DarFK,PapazotosV.Ophthalmomyiasiscausedtrythesheepnasalbot,Oestrue a dead larva detected, treatment options include no treatment for ovis(Oestridae)larvae.intheGenghaziareaofeasternLibya.TrRSocTropMedHyg.1980;74:303- with no inflammatory reaction, vitrectomy for an accessible larva 306. 45 19. botfty:ophlhalmomyiasisextema.CanJ Ophthalmc4.1986;21:92-95. producing inflammation, and laser photocoagulation. HarveyJT.Sheep 20. GarzoziH,LangY,BarkayS. Externalophthalmomyiasiscaused byOestrusovis.tsr J MedSd. In 0. ovis46ophthalmomyiasis, patients sometimes report sneezing 47 1989:25:162-163. or other nasal symptoms. These have generally been self-limited, 21. Sargent6.Lathimni:Myiaseoculo-nasaledel’hommecauseeparl’oestredumouton,ArchInstPasteur suggesting the possibility of a local reaction to larval or adult fly Alger.1952;30:319-322. products which have been carried by tears into the nasal cavity. There has been a case of an 0. ovis larva physically entering the nasolacrimal 46duct, from which it would have access to the nasal and sinus cavities. In these sites, the larvae may persist longer than Page 17 in the 49conjunctivae. Recently, there has been a report of 0. ot4s Continuedon 4 HAWANMEDICALJOURNAL, VOL 56, JANUARY 1997 ’ 12