Considered an emerging disease, “Bobcat Fever” (Cytauxzoon felis) is caused by a blood parasite that affects cats. Bobcats are a known reservoir the organism, and in some cases infected domestic cats have died of the disease. Found originally in the Southeastern U.S., C. felis has been slowly moving north with the tick vectors that carry it.
Cytauxzoon felis is carried most commonly by the Lone Star tick Amblyomma americanum, and sometimes by the American Dog tick Dermacentor variabilis. Because our climate is warming, we expect to see more of these vector-borne diseases moving north to our part of the country, and occurring with greater frequency. So far, cytauxzoon has been documented in cats as far north as Pennsylvania, but D. variabilis is found all over New York, and A. americanum is now widespread on Long Island and Staten Island.
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Maps showing the average minimum January temperatures (°F) in the continental United States: (A) 1970; (B) 2016. Dark Blue = –10 °F; medium blue = 11–20 °F; light blue = 21–30 °F; blue-green = 31–40 °F; gray = 41–50 °F. Photo credits Dr. R. Ryan Lash, Traveler’s Health Branch, DGMQ, Centers for Disease Control and Prevention, Atlanta, GA. Reproduced from: Sonenshine, D.E. Range Expansion of Tick Disease Vectors in North America: Implications for Spread of Tick-Borne Disease. Int. J. Environ. Res. Public Health 2018, 15, 478.
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American Dog tick (Dermacentor variabilis) female. Photo by AHDC Parasitology lab
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American Dog Tick family. Image courtesy of CDC
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Lone Star Tick (Amblyomma americanum), female. Photo by AHDC Parasitology lab
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Lone Star Tick family. Image courtesy of CDC.
Maps showing the average minimum January temperatures (°F) in the continental United States: (A) 1970; (B) 2016. Dark Blue = –10 °F; medium blue = 11–20 °F; light blue = 21–30 °F; blue-green = 31–40 °F; gray = 41–50 °F. Photo credits Dr. R. Ryan Lash, Traveler’s Health Branch, DGMQ, Centers for Disease Control and Prevention, Atlanta, GA. Reproduced from: Sonenshine, D.E. Range Expansion of Tick Disease Vectors in North America: Implications for Spread of Tick-Borne Disease. Int. J. Environ. Res. Public Health 2018, 15, 478.
American Dog tick (Dermacentor variabilis) female. Photo by AHDC Parasitology lab
American Dog Tick family. Image courtesy of CDC
Lone Star Tick (Amblyomma americanum), female. Photo by AHDC Parasitology lab
Lone Star Tick family. Image courtesy of CDC.
What we know about cytauxzoon is rapidly evolving as scientists do more research. We don’t have much information about how it impacts the bobcat population, or how often the disease is transmitted from wild cats to pets. Domestic cats were thought to be the dead-end hosts of the parasite, but there is evidence they can recover from infection and may become carriers. New medications and more rapid diagnosis have improved survival rates from below 25% to closer to 60%.
The CWHL is working with the parasitology lab at the AHDC to develop a PCR (DNA based) test for Cytauxzoon felis. With tick samples from across the state and staff actively collecting bobcat tissues for evaluation, including using our tissue bank, we are digging in to confirm if it is present in New York, its distribution throughout the state, and how much crossover there is between bobcats and domestic cats.
Coming soon to CWHL:
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Thumbnail image: By Alan Vernon (Flickr: Bobcat (Lynx rufus) portrait) [CC BY 2.0 via Wikimedia Commons]