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Year : 1988  |  Volume : 36  |  Issue : 1  |  Page : 41-42

Ophthalmomyiasis externa caused by the sheep nasal botfly Oestrus ovis


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V P Gupta

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PMID: 3253202

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A case Ophthalmomyiasis externa caused by sheep nasal botfly Oestrus ovis in a 10 year old boy is reported. Fifteen larvae of Oestrus ovis were removed from the conjunctiva wish the help of cotton swab sticks Human Ophthalmomyiasis externa caused by oestrus ovis is rare in India.

How to cite this article:
Gupta V P, Baveja UK. Ophthalmomyiasis externa caused by the sheep nasal botfly Oestrus ovis. Indian J Ophthalmol 1988;36:41-2

How to cite this URL:
Gupta V P, Baveja UK. Ophthalmomyiasis externa caused by the sheep nasal botfly Oestrus ovis. Indian J Ophthalmol [serial online] 1988 [cited 2022 May 16];36:41-2. Available from: https://www.ijo.in/text.asp?1988/36/1/41/26162

Infestation of the human eye by the larval form of certain flies is termed as 'Ophthalmomyiasis ! Human Ophthalmomyiasis is classified as Ophthalmomyiasis extema when the larvae are present on the conjunctiva and as Ophthalmomyiasis intema when there is intra­ocular penetration by the larvae.

External Ophthalmomyiasis is most commonly caused by the larva of the sheep nasal botfly Oestrus ovis. Cases of Ophthalmomysasis externa by Oestrus ovis have been reported from various parts of the world [1],[2],[3],[4] particularly in Mediterranean countries, Central America and South Africa. However, Ophthalmomyiasis entema is rare in India as there are only few cases on records. We report a case of Ophthalmomyiasis extema caused by the sheep botflty, Oestrus ovis.

  Case Report Top

A 10 year old male child was brought to the outpatient department of Guru Nanak Eye Centre, Maulana Azad Medical College, New Delhi at 10.00 A M. in the month of March 1986. He complained of sharp pain, foreign body sensation, burning and excessive watering from his right eye after being hit by a fly in his right eye while playing with other children Before coming to the hospital his mother had noted tiny white worm like objects crawling over the eye. She tried to wash them out but there was no relief There was no significant history of ocular or medical problems preceding this.

On examination visual acuity was 6/6 both eyes. Eyelids of the right eye were mildly edematous. Conjunctiva was markedly congested with profuse lacrimation. There was no preauricular lymphadenopathy. Extra ocular movements were normal The most remarkable finding was the presence of white tiny worm like organisms crawling over the conjunctiva and cornea Pupillary reaction was normal Slit-lamp examination revealed a number of small 1-2mm long translucent organisms over the conjunctiva The organisms were motile and actively avoided the light of the slit-lamp. These organisms moved freely over the palpebral and bulbar conjunctiva and were occasionally seen darting over the cornea The organisms were more in the upper temporal aspect of the bulbar conjunctiva.

After topical Lidocaine 4% drops about 15 organisms were removed with the help of cotton swabsticks and fine plane forceps. The organisms were placed in normal saline for identification.

Direct and indirect Ophthalmoscopic examination of fundus after mydriasis did not reveal any evidence of intraocular organisms. Topical antibiotics and steroid drops were prescribed A repeat examination of the anterior segment and fundus after a week was negative.

On examination under the microscope the organisms were identified as the first stage larvae of Oestrus ovis (the sheep nasal botfly) characterized by a pair of sharp dark brown oral hooks connected to the large internal cephalopharyngeal skeleton [Figure - 1] and by tufts of numerous brown hooks on the anterior margin of each body segment [Figure - 2]. The posterior spiracles were found, in the eighth segment.

  Discussion Top

The sheep nasal botfly, Oestrus ovis Linneaeus are large dark gray flies with dark spots on the dorsum of the thorax and abdomen and are covered by a moderate amount of light brown hair [6]. The females dash at their victims and deposit freshly hatched larvae in the nares, on the conjunctiva and occasionally on the lips and in the mouth [6]. The usual hosts are sheep, cattle, horse and deer. Man may serve as an accidental host The inci­dence of larval infestation is favoured by an abundance of flies in the locality'. Human Ophthalmomyiasis occurs mainly in those areas where the density of sheep is relatively low compared with that of human beings [1].

External Ophthalmomyiasis manifests as acute catarrhal conjunctivitis with the symptoms similar to those present in this case. Although Ophthalmomyiasis interna is commonly associated with cattle botfly (Hypoderma bovis) [1] cases have also been reported due to larvae of Oestrus ovis. Ophthalmomyiasis extema caused by Oestrus ovis, therefore, should not be regarded as a benign condition and should be treated promptly to prevent serious complication of intraocular invasion.

Irrigation of the conjunctival sac with normal saline is unsuccessful in washing out the larvae because the organisms grab the conjunctiva firmly with the help of a pair of oral hooks and numerous brown hooks on each body segment After anaestheticing the conjunctiva the larvae should be removed with cotton swab-sticks or with forceps preferably under magnification[7].

  References Top

Zumpt F., S. Afr. Med J. 37 : 425-428, 1963.  Back to cited text no. 1
Janbathsh R, Pirociz N. S, Tirgari S., Agha Mohammadi : Acta Med Iran Iran 20 : 19-26. 1977.  Back to cited text no. 2
Hennessy D.J., Sherrill J.W., Binder P.S. Amer. J. OphthalmoL 84 802-805, 1.977.  Back to cited text no. 3
Wong D. Brit J. OphthalmoL 66 : 786-787, 1982.  Back to cited text no. 4
Chandra D.B. and Agarwal T.N.: Ind J. OphthalmoL Oct 29(3) 199-200, 1981.  Back to cited text no. 5
Beaver P.C., Jung RC. and Cupp E.W. ed: Clinical Parasitology, (TH ED. Philadelphia, P. 687, 1984.  Back to cited text no. 6
Rakusin W.: L, S. Afr. Med J. 44 : 1155-1157, 1970.  Back to cited text no. 7


  [Figure - 1], [Figure - 2]


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