EXTERNAL OPHTHALMOMYIASIS

Abstract

Ophthalmomyiasis is a zoonotic disease most often caused by the larvae of oestrus ovis (sheep fly). The
female O. ovis retains her eggs within her body until they hatch, and then typically deposits her larvae into the
nostrils of sheep and goats. Larvae of Oestrus ovis are obligate parasites of the nasal and sinus cavities of sheep and
goats, so this parasite is widespread in countries where the climate is hot and dry and sheep and goats are numerous.
Therefore, it usually occurs in shepherds and farmers in rural areas, but it has also been observed in urban areas and
in close contact with animals. In addition to oestrus ovis, there are other species that can cause this disease - the
human bot fly (Dermatobia Hominis), midge (Fannia), house fly (Musca domestica) and cattle (Hypoderma).
Ophthalmomyiasis is classified as external if the larvae are present on the lids or conjunctiva, and internal when
there is intraocular penetration of the larvae, which affects the retina and if left untreated can lead to blindness.
Intraocular penetration of larvae, or ophthalmomyiasis interna, is less common worldwide than ophthalmomyiasis
externa. It is known to occur at various anatomical sites including skin, eye, nose, paranasal sinuses, throat,
intestine, and urogenital tract Conjunctival myiasis is the most common form of ophthalmomyiasis, and it is a
relatively mild, self-limited, and benign disease.An ocular involvement occurs in about < 5% of all the cases of
human myiasis.
Risk factors include eye infections, eye sores, advanced age, frailty, poor general health. Symptoms are described as
foreign body sensation with lacrimation, conjunctival hyperemia and pruritus followed by eye pain. These initial
signs and symptoms of ophthalmomyiasis externa may mimic conjunctivitis. All movements of the larva are clearly
visible from the side, which greatly facilitates its detection and diagnosis. Ophthalmomyiasis can be treated
efficiently ,if identified in time The treatment is based on the manual extraction of all larvae under local anesthesia,
followed by washing or rinsing the eyes and local treatment. Prevention has always been better than cure. Good
personal hygiene can avert significant complications caused by ophthalmomyiasis Cases of ophthalmomiasis have
been reported in countries around the world including Afghanistan, Pakistan, Kuwait, Iraq, Libya, Tunisia, Russia,
India, USA, Canada, Croatia Slovenia. In the Republic of North Macedonia in 2022, 4 cases of ophthalmomiasis
were diagnosed and treated at the Shtip Clinical Hospital. It is characteristic that all the patients are men who are
engaged in animal husbandry and agriculture and they are from a rural environment. Myiasis should be considered
as an occupational disease in farmers and shepherds.