The University of Georgia College of Veterinary Medicine

eorgia Veterinary Scholars Program

GVSP Summer 2007 Scholars

Georgia Veterinary Scholar	Faculty Mentor

Shirin Modaresi University of Georgia Class of 2010	Dr. David Peterson

Cytauxzoon felis: Assessing genetic variability in an emerging feline infectious disease

Shirin Modaresia*, Holly M. Brownb, David S. Petersona
Departments of Infectious Diseasesa and Pathologyb, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, 30602, USA

Abstract

Cytauxzoonosis is a highly fatal disease of domestic cats caused by the hemoprotozoal, tickborne parasite, Cytauxzoon felis, that was first detected in the United States in 1973. Domestic cats have since been presumed to be incidental dead-end hosts of C. felis, as the infection almost always results in rapid disease progression and acute death. Recent reports document individual domestic cats that have survived C. felis infection, however, and rare feral cats that appear asymptomatic but are PCR-positive for C. felis DNA. One possible explanation for the apparent decreased pathogenicity in cats is that the parasite is genetically adapting to the domestic cat, allowing for persistent, subclinical infection. The objective of our study is to assess the genetic variability of C. felis over the past 16 years, using banked tissue samples from cats that died of clinical cytauxzoonosis and current blood samples from cats that have survived C. felis infection. Sequencing of the internal transcriber spacer region-2 (ITS-2) of the C. felis genome may allow detection of genetic variability of the C. felis parasite over time as well as a comparison between the acutely fatal C. felis parasite of the last two decades and a potentially less virulent C. felis parasite sporadically found today. We have established a protocol for effective DNA extraction from our formalin-fixed paraffin-embedded tissues. We have successfully performed PCR and subsequent sequencing of the ITS-2 region of the C. felis genome on some of our samples. Initial genetic comparisons of more current C. felis isolates have detected minimal nucleotide variability within the ITS2 region. Our goal for the summer is to complete the C. felis ITS2 genetic sequencing from the remaining banked tissue samples, allowing for genetic analysis and comparison between the different isolates.