Chronic recurrent conjunctivitis due to Thelazia lacrymalis-induced, chronic abscess forming dacryoadenitis in a Warmblood stallion

Chronisch rezidivierende Konjunktivitis infolge Thelazia lacrymalis-induzierter, chronisch abszedierender Dacryoadenitis bei einem Warmbluthengst

Wollanke B, Gerhards H, Pfleghaar S

DOI: 10.21836/PEM20040203
Year: 2004
Volume: 20
Issue: 2
Pages: 131-134

In recent years, Thelazia lacrymalis infections in horses in Germany have been sporadically reported. Usually, the course of this parasitic infection is asymptomatic and rarely diagnosed. Isolated cases of infected horses have developed conjunctivitis or keratitis. This case study presents a 2 year old stallion with marked Thelazia lacrymalis infestation which led to chronic abscess forming dacryoadenitis with severe concurrent bilateral conjunctivitis. The conjunctivitis failed to respond to medical treatment and did not heal until surgical resection of the pathologically changed lacrimal glands was performed. Histological examination of the resected tissue revealed abscess formation and a necrotizing, parasitic dacryoadenitis. Negative consequences due to removal of the lacrimal glands from both eyes were not observed during the following two years. The remaining accessory lacrimal glands beneath the third eyelid, aswell as the palpebral conjunctiva were able to provide the cornea with sufficient fluid. Although the stallion was treated with avermectins 4 weeks prior to submission, the infestation with Thelazia lacrimalis was not eliminated. The development of a readily performed diagnostic test as well as the development of an effective ophthalmic antiparasitic drug are needed to enhance recognition and treat this disease.