Abstract
We present the case of a young male patient who presented with pain, redness and foreign body sensation in his left eye. There was no associated decrease in vision. Three live larvae were removed from his left conjunctival sac and sent to the laboratory for identification. The patient was treated symptomatically and his symptoms were mostly resolved by the following day. The larvae were later identified as the first instar of the sheep nasal botfly. Poor sanitation and exposure to livestock were among the identified risk factors in this case. Physicians must have this as a differential diagnosis for conjunctivitis in patients with risk factors. This is the first reported case of ophthalmomyiasis from Jamaica.
Case report
A 17-year-old male patient presented to the Accident and Emergency department with a one-day history of foreign body sensation in his left eye. He felt something fly into his left eye while chopping grass. He had pain, itching and redness to the affected eye, and noticed a ‘little, flat, white thing’ in his eye.
His vision was 6/5-2 in both eyes. He had mild conjunctival injection in the left eye. Slit-lamp biomicroscopy revealed three mobile larvae (∼1 mm long, brown head and pale bodies) within the conjunctival sac (Figure 1a).
(a) Photograph of the larvae on the conjunctiva, taken at the slit lamp biomicroscope, (b) Photograph of a larva as seen with a light microscope, and (c) Photograph of a larva as seen under high magnification.
The patient’s left eye was anesthetised with proparacaine 0.5% and the larvae removed with a cotton tip applicator and placed in normal saline (0% NaCl solution). The larvae were mounted on microscope slides and examined under a light microscope (LM) (Figure 1b and 1c). LM demonstrated the oral hooks and caudal spines of the first instar of Oestrus Ovis. The patient commenced chloramphenicol and nepafenac eyedrops to his left eye. The next day he had mild residual hyperaemia and was asymptomatic. He had complete resolution of his symptoms at one week.
Discussion
Ophthalmomyiasis is the infestation of the eye with the larvae of insects (Diptera) and can be classified as ophthalmomyiasis interna (ocular penetration of the larvae), ophthalmomyiasis externa (no globe penetration) and orbital myiasis.1,2 Ocular involvement with myiasis is uncommon, occurring in < 5% of myiasis cases. 1 The sheep nasal and cattle botfly have been implicated in ophthalmomyiasis.1,3,4 The sheep nasal botfly (Oestrus Ovis) is the most common cause of opththalmomyiasis in humans, occurring during spring or summer in temperate countries due to the warm temperatures; however, the tropical climate of Jamaica facilitates activity of the adult female flies. Oestrus is an obligate parasite, whose usual hosts are sheep and goats; however, humans may become an accidental intermediate host. 4 The young and immunocompromised who are in close contact with livestock are at a greater risk of contracting ophthalmomyiasis. Substandard living conditions and poor health of livestock potentiate the problem. 3
Our patient had several risk factors. At the time of presentation, he resided in a one-room stone building in rural St. Ann, Jamaica with no available running water. He disposed of his waste in a hole in the ground nearby. His sources of income included planting yam and rearing livestock, consisting of two cows and seven goats, near his home.
While in the human conjunctival sac, the larvae move by peristaltic contractions and may grasp conjunctival tissue with their oral hooks, making them difficult to remove by irrigation. 1 Appendages, such as the oral hooks and caudal spines, may cause mechanical damage to the cornea or conjunctiva. Secondary bacterial infection may occur leading to an acute conjunctivitis. 3 Patients may present with conjunctivitis, conjunctival haemorrhages, keratouveitis and eyelid oedema with erythema. 5 It can result in visually threatening problems such as corneal ulcer, endophthalmitis and blindness.1,5
Health professionals must be aware of this disease as a differential for conjunctivitis in warm climates in patients who work with livestock where there is a high incidence of flies and the risk factor of poor sanitary conditions and hygiene. This is the first case report from Jamaica, a Caribbean island.
Footnotes
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.