Development and evaluation of a PCR assay for the detection of Cytauxzoon felis DNA in feline blood samples Adam J. Birkenheuer a, * , Henry Marr a , A. Rick Alleman b , Michael G. Levy c , Edward B. Breitschwerdt a a Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, NC 27606, United States b Department of Physiological Science, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, United States c Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, United States Received 4 November 2005; received in revised form 7 December 2005; accepted 7 December 2005 Abstract Cytauxzoonosis is an emerging tick borne infectious disease of domestic cats in the United States, caused by the organism Cytauxzoon felis (C. felis). In naturally infected domestic cats the disease is almost always fatal. Currently there are no commercially available molecular or serologic tests to facilitate the antemortem diagnosis of C. felis infection. Clinical and pathological diagnosis of cytauxzoonosis is based on microscopic identification of parasites in tissues or on blood smears. We have developed and evaluated the sensitivity and specificity of a polymerase chain reaction (PCR) based assay for the diagnosis of C. felis infections in feline blood samples. The assay is sensitive enough to detect one copy of a cloned fragment of the C. felis 18S rRNA gene. This PCR assay can be used for the rapid clinical diagnosis of cytauxzoonosis and for epidemiological studies that will better define the geographic distribution of C. felis infection in cats. # 2005 Elsevier B.V. All rights reserved. Keywords: Cytauxzoonosis; Piroplasmosis; Pancytopenia 1. Introduction Cytauxzoon felis is an emerging tick-transmitted apicomplexan protozoal parasite that infects domestic cats (Felis catus). It is presumed to be transmitted to domestic cats via ticks from wild felids such as bobcats (Lynx rufus) and cougars (Felis concolor). In domestic cats cytauxzoonosis is characterized by fever, pancytopenia, multi-organ failure and often results in the death of affected cats (Criado Fornelio et al., 2004; Greene et al., 1999; Hoover et al., 1994; Meier and Moore, 2000; Meinkoth et al., 2000). Due www.elsevier.com/locate/vetpar Veterinary Parasitology 137 (2006) 144–149 * Corresponding author. Tel.: +1 919 513 8288; fax: +1 919 513 6336. E-mail address: ajbirken@ncsu.edu (A.J. Birkenheuer). 0304-4017/$ – see front matter # 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.vetpar.2005.12.007