Myiasis, the infestation of mammalian tissue, is a common reproductive strategy
amongst flies, particularly the myiatic fly genuses. Diagnosis is made when necrotic or live larvae cause discomfort, oedema, and irritation, and are identified under microscopy. Ophthalmomyiasis occurs in arid and tropical climates. Diagnostically, ophthalmomyiasis is divided into external and internal, which ultimately is sight-threatening. It is treated with topical anaesthetic to paralyse the insects, antibiotic or antiparasitic agents to treat secondary infection, viscous substances to asphyxiate the
larvae, and ultimately physical removal of the maggots under local anaesthetic.
To elucidate a case of external ophthalmomyiasis in a rural Queensland setting, including diagnosis and management, so as to prepare clinicians in both a rural and tertiary centre for this rare but sight-threatening condition.
The patient was examined under a slit lamp using fluorescein staining. 3 grub-like creatures with multiple legs and black heads were seen. They demonstrated an aversion to light. The grubs were paralysed with local anaesthetic (oxybuprocaine) and photographed (available), removed with forceps, and collected in formalin and dry specimen jars.
The Princess Alexandra Hospital pathology department could not
identify the species and they were sent off to the Royal Brisbane and Women’s
Hospital where it was determined they were maggots of the species oestrus ovis,
or sheep bot fly.
This is a case study that shows a standard presentation, etiology, and management of
external ophthalmomyiasis in subtropical Queensland, Australia.