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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
Outline
•What is Cytauxzoonosis?
•Case Study: – TnnssTennessee cats
• Prevention
• Future Research Goals
What is Cytauxzoonosis?
• 1st reported in the late • Bobcats are asymptomatic 1970’s in Missouri carriers
• Caused by the • Found throughout the ppprotozoan parasite south-central & Cytauxzoon felis southeastern US
• Affects wild & • Transmitted by ticks domestic felines
• Serious illness, often fatal
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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 – The schizonts develop protozoan infects white blood cells (leukocytes) into merozoites
– Undergoes asexual – Host cells rupture and reproduction forming protozoan enters the schizonts blood where they infect the red blood cells – The cells become engorged with schizonts (erythrocytes) and line the veins in many organs of the body – Destruction of blood – Causing obstruction cells of blood flow and tissue ischemia
Clinical Signs & Diagnostics
SIGNS DIAGNOSTICS
• Blood Smears and Staining: • Nonspecific e.g. lethargy – piroplasms in erythrocytes • Depression – schizonts in leukocytes • Anorexia • Direct Fluorescent Antibody • Icterus test (tissue phase)
• Dehydration • Microfluorometric Immunoassay • Dyspnea System (serum antibody)
• Fever; 103-107ºF • Often misidentified as • Hypothermia & coma generally Haemobartonella felis are signs of terminal disease • Polymerase Chain Reaction (PCR) Disease progresses EXTREMELY quickly… diagnosis is usually made during postmortem examination!
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Treatment
• Supportive Care
• Anti-protozoal drugs – clear infection – RcvrRecover but rminremain parasitemic
• Goal: stop replication
• More cases; variable severity
Transmission: Reservoir Hosts
Bobcats Domestic cats (Lynx rufus) (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
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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
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Case Study: Tennessee
Tennessee case study data provided by Dr. Charles Faulkner, UTCVM
Case Study: Tennessee
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
Case Study: Tennessee
Spreading? • Global Warming: – Increasingly associated with numerous EID’s – Vegetation patterns: • changes in tttemperature & 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
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Case Study: Tennessee
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
Case Study: Tennessee
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?
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Future Research??
• Basic epidemiology • Prevalence studies of C. felis of domestic cats in • Genetic variability ‘hot spot’ areas of strains •Treatment • Domestic cats as – Chemoprophylaxis reservoirs • Vaccine Tennessee – Blood/Tick collection from Bobcats for PCR/microscopy – Fill in spatial & temporal data gap with more cases – GIS analysis
Interested?
More information at:
UTCVM Parsitology: E-mail [email protected]
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
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Questions??
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