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Year : 2020  |  Volume : 8  |  Issue : 3  |  Page : 117-119

Unilateral acute conjunctivitis caused by Oestrus ovis larva: A rare case report from Western India

1 Department of Ophthalmology, C. U. Shah Medical College and Hospital, Surendranagar, Gujarat, India
2 Department of Microbiology, C. U. Shah Medical College and Hospital, Surendranagar, Gujarat, India

Date of Submission25-Nov-2019
Date of Decision13-Dec-2019
Date of Acceptance11-May-2020
Date of Web Publication4-Dec-2020

Correspondence Address:
Aruna Kumari R. Gupta
Department of Ophthalmology, C. U. Shah Medical College and Hospital, Dhudrej Road, Surendranagar - 363 001, Gujarat
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jcor.jcor_100_19

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External ophthalmomyiasis is a relatively rare condition caused by infestation of ocular tissue by the larva of Oestrus ovis (sheep botfly) which is a parasite of sheep and goats. We present a case of ophthalmomyiasis caused by O. ovis, from Western India. The patient presented with left eye acute conjunctivitis associated with conjunctival chemosis and watering. The larvae of O. ovis were seen in the bulbar and palpebral conjunctiva. Prompt removal of the larvae was done from the conjunctiva which helped in relieving the symptoms. It is important for ophthalmologists to be aware of ophthalmomyiasis, as this is often misdiagnosed as acute conjunctivitis.

Keywords: Conjunctivitis, Oestrus ovis, ophthalmomyiasis, sheep botfly, western India

How to cite this article:
R. Gupta AK, Patel AP, Nathwani YP, Kyada GC, Kikani K. Unilateral acute conjunctivitis caused by Oestrus ovis larva: A rare case report from Western India. J Clin Ophthalmol Res 2020;8:117-9

How to cite this URL:
R. Gupta AK, Patel AP, Nathwani YP, Kyada GC, Kikani K. Unilateral acute conjunctivitis caused by Oestrus ovis larva: A rare case report from Western India. J Clin Ophthalmol Res [serial online] 2020 [cited 2022 Sep 26];8:117-9. Available from: https://www.jcor.in/text.asp?2020/8/3/117/302191

Myiasis is an infection of tissue and organ of animals or man by fly larvae.[1] Ophthalmomyiasis is the infestation of the human eye by the larval form of certain flies. Ophthalmomyiasis is classified as external ophthalmomyiasis if the larvae are present on the conjunctiva and internal ophthalmomyiasis when there is intraocular penetration of larvae. External ophthalmomyiasis is most commonly caused by the larva of the sheep nasal botfly, Oestrus ovis.[2] Cases of external ophthalmomyiasis have been reported from various parts of the world.[3],[4],[5],[6],[7] However, external ophthalmomyiasis is rare in India, as there are only few cases on records.[8],[9],[10],[11],[12]

We report a case of external ophthalmomyiasis due to O. ovis from urban area of North Gujarat.

  Case Report Top

A 52-year-old male patient reported to the ophthalmology outpatient department with complaints of severe foreign-body sensation, redness, and watering from his left eye. He had a history of something hitting his left eye while driving a scooter 2 days ago in the evening. He was completely asymptomatic before that and had no history of any ocular or systemic disease or of any allergy. On examination, the uncorrected visual acuity of the right eye was 6/9 improving to 6/6p with pinhole and uncorrected visual acuity of the left eye was 6/9 and was not improving with pinhole. His left eye showed mild lid edema, profuse lacrimation, and conjunctival congestion and mild chemosis. Slit-lamp examination revealed tiny translucent worms, 1–2 mm in size, with dark heads, crawling over the bulbar conjunctiva and fornix [Figure 1]. These larvae were photosensitive and were moving very rapidly on exposure to bright slit-lamp light and on touch by cotton bud. Rest of the eye examination and the other eye were within normal limits. The larvae were removed using cotton swabs under local anesthetic (proparacaine 1% eye drops) and were mounted on a glass slide and sent to the microbiology department for identification.
Figure 1: Oestrus ovis larva in the left eye of the patient

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On microscopic examination, they were identified as first-stage larvae of O. ovis based on their spindle shape and the presence of a pair of sharply curved mouth hooks. Laboratory examination revealed 2 mm long milky white worms with spindle-shaped skeleton, multiple segments, and intersegmental spine bands. A pair of sharp dark brown oral hooks was attached to internal cephalopharyngeal skeleton, and tuffs of numerous brown hooks were seen on the margins of each body segment [Figure 2]. They were identified as larvae of O. ovis. The patient was started with topical moxifloxacin (0.5%) eye drops. He was lost to follow-up.
Figure 2: Microscopic photograph of first stage larva of Oestrus ovis

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  Discussion Top

Ophthalmic myiasis is mostly caused by O. ovis which is a parasite of sheep and goats.[2] Animals such as cattle, sheep, horse, deer, and rodents are the natural hosts of the fly O. ovis, and human is an accidental host. The adult female fly swarms around the head of sheep and goats and lays larvae around the nostrils from where they migrate to sinuses and develop. After several months, the mature larvae are dropped on the ground by sneezing. In the ground, they further develop to pupa stage. The adult fly emerges from the pupa in 3–6 weeks.

Occasionally, the fly accidentally strikes the human eye and ejects larvae on the ocular surface causing external ophthalmomyiasis. An interesting feature of O. ovis is that it can deposit larvae while still in flight. The fly darts close to the eyes or nostrils and ejects a stream of larvae into the target area.[12]

Larvae of O. ovis are unable to survive in human eye and usually die within 10 days. As the larvae do not have proteolytic enzymes, they do not generally penetrate into deeper layers and present mostly as acute catarrhal conjunctivitis, foreign-body sensation, lacrimation, redness, subconjunctival hemorrhage, itching, and mild lid swelling, but it may get embedded into conjunctiva.[12] Presentation can be in the form of peripheral corneal infiltration and superficial punctuate keratitis[13],[14] or keratouveitis.[15] The symptoms are due to foreign-body effect, infection, or allergic reaction to the larva. Addition of topical anti-inflammatory and antibiotics helps in taking care of any allergic reaction to the larva and prevention of secondary infection.

Ocular irrigation does not remove the larvae; it has to be removed physically with the help of a cotton bud or forceps. Earlier reported cases occurred in farmers and shepherds in spring and summer;[8],[10],[16] similarly, our case also presented in spring season, but our patient was a barber and the infestation was by chance while driving. As mentioned above, the fly must have accidentally entered the patient’s eye while the patient was driving and ejected larva on the ocular surface causing external ophthalmomyiasis.

  Conclusion Top

External ophthalmomyiasis is rarely reported from Gujarat, and thus, this report would alert ophthalmologist regarding larval conjunctivitis and the need for timely diagnosis and treatment of this rare infestation. As similar presentation may be caused by acute conjunctivitis, extraocular foreign bodies, and chemical or physical injuries, a very careful examination under magnification must be done in all such cases to rule out ocular myiasis.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Pandey A, Madan M, Asthana AK, Das A, Kumar S, Jain K. External ophthalmomyiasis caused by Oestrus ovis: A rare case report from India. Korean J Parasitol 2009;47:57-9.  Back to cited text no. 1
Glasgow BJ, Ophthalmomyiasis. Chapter 108. In: Pepose JS, Holland GN, Wilhelmus KR, editors. Ocular Infections and Immunity. 1st ed. St Louis, Missouri, USA: Mosby publishers; 1996. p. 1505-15.  Back to cited text no. 2
Amr ZS, Amr BA, Abo-Shehada MN. Ophthalmomyiasis externa caused by Oestrus ovis L. in the Ajloun area of northern Jordan. Ann Trop Med Parasitol 1993;87:259-62.  Back to cited text no. 3
Patel SJ. Extra-ocular myiasis due to the larva of Oestrus ovis. East Afr Med J 1975;52:167-9.  Back to cited text no. 4
McDermott S, Schafer MD. Ophthalmomyiasis due to Oestrus ovis in South Australia. Med J Aust 1983;1:129-30.  Back to cited text no. 5
Thompson JH Jr., Knutson LV, Culp OS. Larva of Scenopinus sp. (diptera: Scenopinidae) causing human urogenital myiasis? Mayo Clin Proc 1970;45:597-601.  Back to cited text no. 6
Victor R, Bhargva K. Ophthalmomyiasis in Oman: A case report and comments. Wilderness Environ Med 1998;9:32-5.  Back to cited text no. 7
Misra S, Misra N, Reddy B. External ophthalmomyiasis by oestrus ovis: An unknown endemic eye disease in rural parts of central India. Trop Doct 2008;38:120-2.  Back to cited text no. 8
Jayaprakash K, Karthikeyan A. Ocular myasis and associated mucopurulent conjuctivitis acquired occupationally: A case study. Indian J Occup Environ Med 2008;12:20-2.  Back to cited text no. 9
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Nigwekar S. Ophthalmomyiasis externa: A case report. Pravara Med Rev 2009;4:28-30.  Back to cited text no. 10
Narayanan S, Jayaprakash K. Incidence of ocular myiasis due to infection with the larva of oestrus ovis (Oestridae Diptera). Indian J Ophthalmol 1991;39:176-8.  Back to cited text no. 11
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Khurana S, Biswal M, Bhatti HS, Pandav SS, Gupta A, Chatterjee SS, et al. Ophthalmomyiasis: Three cases from North India. Indian J Med Microbiol 2010;28:257-61.  Back to cited text no. 12
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Gholamhossein Y, Behrouz H. External ophthalmomyiasis presenting to an emergency department: Corneal findings as a sign of Oestrus ovis. Korean J Ophthalmol 2013;27:341-4.  Back to cited text no. 13
Sreejith RS, Reddy AK, Ganeshpuri SS, Garg P. Oestrus ovis ophthalmomyiasis with keratitis. Indian J Med Microbiol 2010;28:399-402.  Back to cited text no. 14
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Jenzeri S, Ammari W, Attia S, Zaouali S, Babba H, Messaoud R, et al. External ophthalmomyiasis manifesting with keratouveitis. Int Ophthalmol 2009;29:533-5.  Back to cited text no. 15
Jayaprakash K, Karthikeyan A. Ocular myasis and associated mucopurulent conjuctivitis acquired occupationally: A case study. Indian J Occup Environ Med 2008;12:20-2.  Back to cited text no. 16
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