Severe ulcerative keratitis in ocular cowpox infection


Dear Editor, In February 2009, a 40-year-old woman attended the Dept. of Ophthalmology of the RWTH Aachen University with red eye symptoms on the right side. Previous dermatological investigation revealed a cowpox skin lesion under the collarbone 1 week after exposure to a pet rat. The transmission via smear infection from the pet rat after multiple exposures was proven. Six days after the occurrence of the dermatological symptoms, ophthalmic examination was performed and revealed a phlycten-like conjunctival lesion with mild conjunctival injection. Despite topical anti-inflammatory and antibiotic therapy, conjunctival injection was progressive, with increasing chemosis of the nasal conjunctiva. Four weeks after the first ophthalmic examination, the cornea showed progressive infiltration. A swab for bacteriological examination showed an infection with Staphylococcus aureus. The corneal infiltrate resolved under systemic and topical antibiotic therapy in the following weeks, but the cornea showed progressive erosion and limbal ulceration tending to perforate (Fig. 1). A corneal swab was analysed for poxviruses by quantitative real-time PCR and sequencing of the entire open reading frame of the haemagglutinin gene (924 bp, Accession number JF330118) to confirm the diagnosis of ocular cowpox infection. During follow-up, the anterior chamber showed a slight inflammation with small endothelial corneal precipitates. To prevent further limbal ulceration of the cornea, in-house-produced kallikrein-inhibitory eye drops (i.e., aprotinin) were added. Four months after the appearance of ocular symptoms, another specimen of the cornea was taken, and the PCR for cowpox virus was negative. Then, topical steroid eye drops were added to suppress the immunological limbal and anterior chamber response. The following months presented severe persistent subtotal corneal erosion due to limbal stem cell insufficiency. Anterior chamber inflammation and corneal ulceration was under control (Fig. 2). Human cases of cowpox virus infections are commonly described after transmission from domestic cats and directly from rats [1]. A specific antiviral cowpox therapy is not known. There are some reports of the use of cidofovir, an inhibitor of viral DNA-polymerase, in severe systemic cowpox infections [2]. Cowpox infection typically is a selflimiting disease, resulting in scarring of the skin lesions. In 2008, a cluster of cowpox virus infections in humans was reported in Northern and Southern Germany [3, 4], being transmitted by pet rats. The authors assumed a potential further increase in infection rates in the future. The first case report of ocular cowpox infection in 1987 by Hall and Stevens referred to a 28-year-old veterinary

DOI: 10.1007/s00417-012-2138-x

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@article{Schwarzer2012SevereUK, title={Severe ulcerative keratitis in ocular cowpox infection}, author={Hendrik Schwarzer and Andreas Kurth and Martin Hermel and Niklas Plange}, journal={Graefe's Archive for Clinical and Experimental Ophthalmology}, year={2012}, volume={251}, pages={1451-1452} }