Avian philophthalmiasis is the name of the disease caused by infestation with the avian eye fluke, Philophthalmus gralli
that invade the conjunctival and orbital tissues of the eyes of domestic and wild birds. This eye fluke causes conjunctivitis and keratitis (inflammation of the cornea). In severe cases, corneal ulcers, perforation and blindness may also occur. There has been an increase in reports of avian philophthalmiasis in captive and wild birds, especially ostriches, tinamus major birds, and greater Rheas. The most frequent clinical signs observed in infested birds include conjunctivitis, epiphora (excessive lacrymation), pruritus (itching), blepharitis, ocular discharge, blepharospasm (involuntary eye closure), subconjunctival hemorrhage, and swelling of the eyelids.
How the Avian Eye Fluke is Transmitted to Chickens
Mollusks, snails, bivalves, aquatic insect larvae, crustaceans, frogs, fish and reptiles serve as intermediate hosts of P. gralli
. Two species of mollusks, the Red-rim Melania (Melanoides tuberculata
) and the Quilted melanie (Tarebia granifera
) in particular. P. gralli
is transmitted to chickens through ingestion of the host or direct contact with them in the water.
Diagnosis and Treatment of Avian Philophthalmiasis
Avian philophthalmiasis is diagnosed by your veterinarian through an ophthalmic exam. P. gralli
can be visualized in the conjunctival sac and under the third eyelid. Treatment has to be performed by your veterinarian. It consists of the mechanical removal of P. gralli
with a swab or forceps and/or by flushing the conjunctival sac of the eyes.