Infectious keratoconjunctivitis in red deer (Cervus elaphus) in Poland - A case report

Infectious keratoconjunctivitis (IKC) has not been observed in European deer (Cervus elaphus). Our case concerned two red deer bulls in a natural environment, which had orientation disorders and/or circle movement. A detailed post-mortem examination of one of the bulls revealed extensive conjunctivitis in both eyes, clouding and ulceration of the cornea. There were no lesions in the other organs, particularly in the central nervous system (CNS). The histopathological examination of the eyeballs showed corneal epithelium erosions and vascularisation and an inflammatory infiltration of the stroma. Descemet's membrane was found to be disrupted and the corneal stroma was fused with the iris. The remaining structure of the eye did not show any lesions. Furthermore, the polymerase chain reaction analysis for OvHV-1, BHV-1, BHV-5, CapHV-1, CcHV-1, and EHV-1 showed negative results. In the agar culture, only single bacteria were present. There were no Thelazia spp. worms in the conjunctival sac, but numerous Lipoptena cervi flies were present on the skin in the eye region and on the corneal surface. The findings of our case study and those reported in the literature suggest that IKC is a polyetiological disease, where the composition of the pathogenic agents may differ from case to case. The present study suggests that the mechanical irritation of L. cervi parasites could be a contributing factor to the corneal damage, infection and chronic inflammation resulting in a loss of vision in red deer.