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CASE REPORT
Year : 2015  |  Volume : 7  |  Issue : 1  |  Page : 13-15

External ophthalmomyiasis caused by sheep botfly Oestrus ovis Larva in South of Andhra Pradesh


1 Department of Ophthalmology, Narayana Medical College Hospital, Chintareddypalem, Nellore, Andhra Pradesh, India
2 Department of Advanced Research Centre, Narayana Medical College Hospital, Chintareddypalem, Nellore, Andhra Pradesh, India

Date of Web Publication17-Jun-2015

Correspondence Address:
Chandrasekhar Gujjula
Department of Ophthalmology, Narayana Medical College Hospital, Chintareddypalem, Nellore - 524 003, Andhra Pradesh
India
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DOI: 10.4103/1858-540X.158991

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  Abstract 

Myiasis of different organs has been reported in various regions of the world. We report a human case of external ophthalmomyiasis caused by the larva of a sheep botfly, Oestrus ovis, for the first time from Nellore district of Andhra Pradesh, India. A 19-year-old female who is a nursing student presented with symptoms of excessive watering, pain and foreign body sensation in the left eye. The larvae, 10 in number, were observed in bulbar conjunctiva and fornix. After removal of larvae, she showed symptomatic improvement in 1 day.

Keywords: Lacrimation, ophthalmomyiasis, Oestrus ovis


How to cite this article:
Gujjula C, Regalla S, Putti P, Shaik MV. External ophthalmomyiasis caused by sheep botfly Oestrus ovis Larva in South of Andhra Pradesh. Sudanese J Ophthalmol 2015;7:13-5

How to cite this URL:
Gujjula C, Regalla S, Putti P, Shaik MV. External ophthalmomyiasis caused by sheep botfly Oestrus ovis Larva in South of Andhra Pradesh. Sudanese J Ophthalmol [serial online] 2015 [cited 2020 Nov 27];7:13-5. Available from: https://www.sjopthal.net/text.asp?2015/7/1/13/158991


  Introduction Top


Myiasis is the infestation of tissues and organs of animals or man by fly larvae. The most common site of infestation is skin wound. Less common sites are eyes, nose, paranasal sinuses, throat and urogenital tract. [1],[2],[3],[4],[5] Ophthalmomyiasis is classified as ophthalmomyiasis externa if larvae are present on conjunctiva and ophthalmomyiasis interna if there is intraocular penetration of the larvae. Cases of ophthalmomyiasis externa have been reported from various parts of the world like Iran, New Zealand, Brazil and Mediterranean region. [2],[5],[6],[7],[8] These cases are very rare in India and there are only few reported cases. [9],[10],[11],[12] To the best of our knowledge no case of ophthalmomyiasis externa caused by Oestrus ovis has been reported from this part of India in recent years.


  Case report Top


A 19-year-old female of first year graduate nursing student came to our outpatient department (Narayana medical college Hospital) on 6-8-2012 with a 1 day history of foreign body sensation, pain and excessive watering of left eye. She gave a history of roaming in her hostel garden the previous evening. She was absolutely fine before that and there was no significant ocular or medical history preceding the present complaint. She sat under a tree for some time and suddenly felt some pain in left eye and foreign body sensation probably due to the mucous drop containing larva of sheep botfly. Sheep botfly usually inhabits in rural area where cattle are present. Our hospital is located in the rural area (Chinthareddy Palem, Nellore rural). The patient might have come into contact with the larva accidentally.


  On examination Top


Visual acuity of right eye was 6/12 with pinhole improving to 6/9. Visual acuity of left eye was 6/12 and was not improving with pinhole. Eye lids of both eyes were normal. Conjunctiva was congested with profuse lacrimation. Extraocular movements were full.


  On slit-lamp examination Top


Tiny translucent worms, 1-2 mm in size, with dark heads, crawling over the bulbar conjunctiva, fornix and cornea were visible. The cornea showed isolated multiple epithelial defects which were probably due to the movement of the larvae over it. Using topical anesthesia (propacaine eye drops) these larvae were removed with sterile cotton swabs. These larvae were mounted on slide and sent to microbiology lab for identification. In total 10 larvae were removed from the left eye [Figure 1]. Examination of the right eye was normal. Topical anti-histaminic and topical antibiotic drops were prescribed. After 2 days the patient came for the follow up, she was relieved of the symptoms and conjunctivitis.
Figure 1: Identification of Oestrus ovis in the left eye of the patient

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  Microbiology Top


The larvae mounted on the slide were carefully examined and photographed under a microscope. They were identified as larvae of O. ovis (sheep botfly), which is a larviparous dipteran based on their spindle shaped skeleton. The larvae also showed a pair of sharp dark oral hooks on anterior margin of each body segment. Posterior spiracles were also found [Figure 2].
Figure 2: Larva of Oestrus ovis, 100×. A wet mount showing the spindle-shaped skeleton and dark brown oral hooks of an Oestrus ovis larva extracted from the patient

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  Discussion Top


Ophthalmomyiasis due to O. ovis was described for the first time in 1947 by James. [6],[8],[13] The sheep botfly, O. ovis, is a large dark gray fly with dark spots on the dorsum of the thorax and abdomen, and are covered by moderate amount of light brown hair. [14],[15] Sheep botflies commence life as eggs within the female which are fertilized and hatched to larvae of 1 mm within the body of female. The female then deposits a few larvae, while on the wing, within a tiny mucous drop directly into the nostril of the host animal. The larvae travel to the nasal sinuses where they grow and moult into the second stage larvae. This stage of larvae can reach up to a size of 20 mm. After attaining their maximum size they drop to the ground through nasal secretions. Inside the ground it metamorphoses into an adult fly within a time period of 3-9 weeks. The adults do not feed during their 2-4 weeks of adult life. Man is an accidental host in this cycle and is infested by the first stage larvae. Ophthalmomyiasis externa manifests as acute catarrhal conjunctivitis with symptoms similar to those presented in this case. Therefore, ophthalmomyiasis externa caused by O. ovis should not be regarded as a benign condition and should be treated promptly to prevent serious complications such as corneal ulcer, decreased vision, and invasion into eye globe causing endophthalmitis, iridocyclitis and even blindness. However, none of the complications were encountered in our case. All the previous cases which have been reported occurred in farmers and shepherds in spring and summer. [9],[10],[11] But our case is a rare one as our patient is a student and presented in rainy season. The present case highlights the awareness among ophthalmologists regarding larval conjunctivitis and the need for timely diagnosis and treatment of the rare infestation.

 
  References Top

1.
Al-Dabagh M, Al-Mufti N, Shafiq M, Al-Rawas AY, Al-Saffar S. A second record from Iraq of human myiasis caused by larvae of the sheep botfly Oestrus ovis L. Ann Trop Med Parasitol 1980;74:73-7.  Back to cited text no. 1
    
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. 2
    
3.
Katz SI, Taylor R. Cutaneous myiasis. South Med J 1971;64:759-60.  Back to cited text no. 3
    
4.
Keller AP Jr, Keller AP. 3 rd . Myiasis of the middle ear. Laryngoscope 1970;80:646-50.  Back to cited text no. 4
    
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. 5
    
6.
Patel SA, Suleman SK. Treatment of chronic and subacute infections of bone by means of continuous instillation of Rifamycin S.V. East Afr Med J 1975;52:396-404.  Back to cited text no. 6
    
7.
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. 7
    
8.
Victor R, Bhargva K. Ophthalmomyiasis in Oman: A case report and comments. Wilderness Environ Med 1998;9:32-5.  Back to cited text no. 8
    
9.
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. 9
    
10.
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. 10
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11.
Nigwekar S. Ophthalmomyiasis externa: A case report. Pravara Med Rev 2009;4:28-30.  Back to cited text no. 11
    
12.
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. 12
[PUBMED]  Medknow Journal  
13.
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. 13
    
14.
Gupta VP, Baveja UK. Ophthalmomyiasis externa caused by the sheep nasal botfly Oestrus ovis. Indian J Ophthalmol 1988;36:41-2.  Back to cited text no. 14
[PUBMED]  Medknow Journal  
15.
Beaver PC, Jung RC, Cupp EW. Clinical parasitology. Philadelphia: Lea & Febiger; 1984. Trypanosoma cruzi, 88-96.  Back to cited text no. 15
    


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  In this article
Abstract
Introduction
Case report
On examination
On slit-lamp exa...
Microbiology
Discussion
References
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