Veterinary Parasitology 193 (2013) 297–301 Contents lists available at SciVerse ScienceDirect Veterinary Parasitology jo u rn al hom epa ge : www.elsevier.com/locate/vetpar Short Communication Canine ocular onchocercosis in the United States is associated with Onchocerca lupi Amber L. Labelle a,∗ , Carol W. Maddox b , Joshua B. Daniels c , Saraswathi Lanka d , Therese E. Eggett d , Richard R. Dubielzig e , Philippe Labelle f a Department of Veterinary Clinical Medicine, University of Illinois Urbana-Champaign, 1008 West Hazelwood Drive, Urbana, IL 61802, United States b Department of Pathobiology, Veterinary Diagnostic Laboratory, University of Illinois Urbana-Champaign, 2001 South Lincoln, Urbana, IL 61802, United States c Department of Veterinary Clinical Sciences, The Ohio State University, 601 Vernon L Tharp Street, Columbus, OH 43210, United States d Veterinary Diagnostic Laboratory, University of Illinois Urbana-Champaign, 2001 South Lincoln, Urbana, IL 61802, United States e Department of Pathobiological Sciences, Comparative Ocular Pathology Laboratory, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI 53706, United States f Antech Diagnostics, 1111 Marcus Avenue, Lake Success, NY 11042, United States a r t i c l e i n f o Article history: Received 30 August 2012 Received in revised form 24 November 2012 Accepted 4 December 2012 Keywords: Onchocerca lupi Helminth PCR Canine Ocular onchocerciasis a b s t r a c t Canine ocular onchocerciasis has a worldwide distribution and has been associated in Europe with Onchocerca lupi based on morphologic and molecular analysis. In the United States, canine ocular onchocerciasis is reportedly associated with Onchocerca lienalis. This association is based solely on histopathologic examination of ocular tissues. The purpose of this study was to use molecular analysis of formalin-fixed, paraffin-embedded canine ocular tissue to determine the genetic identity of Onchocerca associated with canine ocu- lar onchocerciasis in the United States. PCR and DNA sequencing of the mitochondrial cytochrome oxidase I (cox1) and NADH hydrogenase 5 (nd5) genes demonstrated >99% similarity between the sequences obtained from canine ocular tissues previously diag- nosed with onchocerciasis. The obtained sequences were most similar to O. lupi (>99% similarity). This report confirms for the first time that O. lupi is associated with canine ocular onchocerciasis in the United States, contrary to previously published reports. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Onchocerciasis is caused by infection with the filarid nematode, Onchocerca. Canine ocular onchocerciasis is associated with granulomatous masses of the adnexa and orbital soft tissues, resulting in periocular swelling, ocular pain, blepharitis, keratitis, uveitis, exophthalmos and vision loss (Sreter and Szell, 2008). Canine ocular onchocerciasis has a worldwide distribution, including the southwestern United States, western Europe and northern Asia (Faisca et al., 2010; Gardiner et al., 1993; Hermosilla ∗ Corresponding author. Tel.: +1 217 244 3364; fax: +1 217 244 9554. E-mail address: alabelle@illinois.edu (A.L. Labelle). et al., 2005; Komnenou et al., 2002, 2003; Orihel et al., 1991; Papaioannou et al., 2004; Rodonaja, 1967; Saenchez et al., 2012; Santiago Mejia et al., 1994; Sreter and Szell, 2008; Sreter et al., 2002a; Sreter-Lancz et al., 2007; Szell et al., 2001a; Zarfoss et al., 2005). First reported in a feral wolf in Russia, the causative organism was named Onchocerca lupi (Rodonaja, 1967). Since that initial report, canine ocu- lar onchocerciasis has been identified only in domesticated dogs. The first published report of canine onchocercia- sis in the US did not identify the organism beyond the genus level, but several subsequent US reports evaluat- ing formalin fixed, paraffin embedded (FFPE) canine globes or episcleral tissue suggested the causative organism as Onchocerca lienalis (Eberhard et al., 2000; Gardiner et al., 1993; Orihel et al., 1991; Zarfoss et al., 2005). Organism 0304-4017/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.vetpar.2012.12.002