Cytauxzoonosis: A tick-transmitted parasite of domestic and wild cats in the southeastern U.S. Michelle Rosen Center for Wildlife Health Department of Forestry, Wildlife, & Fisheries What is Cytauxzoonosis? Case Study: Tennessee cats Outline Prevention Future Research Goals What is Cytauxzoonosis? 1 st reported in the late 1970 s in Missouri Bobcats are asymptomatic carriers Caused by the protozoan parasite Cytauxzoon felis Affects wild & domestic felines Found throughout the south-central & southeastern US Transmitted by ticks Serious illness, often fatal 1
Cytauxzoonosis: Disease Agent Cytauxzoon felis Intracellular Hemoprotozoan Parasite Order Piroplasmida, Family Theileridae 2 life stages: Leukocytic (in white blood cells) Erythrocytic (in red blood cells) Infected red blood cells C. felis: Life Cycle STAGE 1: STAGE 2: Begins when the protozoan infects white blood cells (leukocytes) The schizonts develop into merozoites Undergoes asexual reproduction forming schizonts The cells become engorged with schizonts and line the veins in many organs of the body Causing obstruction of blood flow and tissue ischemia Host cells rupture and protozoan enters the blood where they infect the red blood cells (erythrocytes) Destruction of blood cells Clinical Signs & Diagnostics SIGNS Nonspecific e.g. lethargy Depression Anorexia Icterus Dehydration Dyspnea Fever; 103-107ºF Hypothermia & coma generally are signs of terminal disease DIAGNOSTICS Blood Smears and Staining: piroplasms in erythrocytes schizonts in leukocytes Direct Fluorescent Antibody test (tissue phase) Microfluorometric Immunoassay System (serum antibody) Often misidentified as Haemobartonella felis Polymerase Chain Reaction (PCR) Disease progresses EXTREMELY quickly diagnosis is usually made during postmortem examination! 2
Treatment Supportive Care Anti-protozoal drugs clear infection Recover but remain parasitemic Goal: stop replication More cases; variable severity Transmission: Reservoir Hosts Bobcats (Lynx rufus) Domestic cats (Felis catus ) Transmission: Ticks Dermacentor variabilis (American Dog Tick) Amblyomma americanum (Lone Star Tick) Ticks are likely infected as nymphs feeding on parasitemic Bobcats Domestic cats acquire the parasite from adult ticks infected by transstadial transmission 3
Transmission: Ticks Distribution C. felis distribution Lone star tick distribution Dog tick distribution Habitats associated with infected cats Dog tick Lone star tick Reichard et al. 2008 Land use cover types with a 100-m buffer zone around address matched C. felis cases 4
Tennessee case study data provided by Dr. Charles Faulkner, UTCVM Unpublished data was used in this presentation and has been removed in order to post the power point on the University of Tennessee, Graduate Student Seminar Series Website. An brief description of information presented: C. felis was first identified in Tennessee in 1989 by Dr. Barry Fly, from a middle TN county. Over the past 8 years, limited case data has been collected by CE Kord Animal Disease Laboratory in Nashville. This case data suggests C. felis is spreading throughout the state. However, because this is not a reportable disease the true prevalence is underestimated. Provided by Dr. C. Faulkner, UTCVM Spreading? Global Warming: Increasingly associated with numerous EID s Vegetation patterns: changes in temperature t & rainfall affecting tick populations TN Bobcat populations? increasing in numbers spreading in distribution Tick-borne parasitic disease Obligate relationship w/ ticks and the reservoir Provided by Dr. C. Faulkner, UTCVM 5
Increasing Bobcat Populations Long lived (6-8 yrs) Low adult mortality rate (~3%) reproductively active through adulthood w/ 2-4 offspring annually Preference for areas w/ rocky shallow soil, broken terrain, shrub cover-recovering forests Recent trends in precipitation, temperature and pulp/chip logging in middle TN/ Plateau counties have resulted in expansion of suitable bobcat habitat Also favorable for increasing tick populations Provided by Dr. C. Faulkner, UTCVM Reichard et al. 2008 Interface between domestic cats, wild felids, and ticks! Prevention Fipronil is the only monthly tick repellant product safe for cat use Owners should keep cats indoors during tick season Be observant for signs of disease during tick season: cats should be taken to the veterinarian anytime Cytauxzoonosis is suspected Lethary, depression, jaundice, Habitat management: Backyard acaricide application? 6
Future Research?? Basic epidemiology of C. felis Genetic variability of strains Domestic cats as reservoirs Tennessee Blood/Tick collection from Bobcats for PCR/microscopy Fill in spatial & temporal data gap with more cases GIS analysis Prevalence studies of domestic cats in hot spot areas Treatment Chemoprophylaxis Vaccine Interested? More information at: UTCVM Parsitology: E-mail parasitology@utk.edu Acknowledgements Dr. Charles Faulkner, UTCVM Parasitology Elisabeth Burress for info on the Scott Co cases Jane Hardcastle for info on the Blount Co cases Barry Fly for the historical perspective of Cytauxzoon in TN Dr. Ed McKinley, C.E. Kord State Diagnostic Lab Dr. Gray Anderson, TWRA UTCVM Parasitology 7
Questions?? 8