{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,10]],"date-time":"2026-02-10T17:38:58Z","timestamp":1770745138514,"version":"3.49.0"},"reference-count":12,"publisher":"Oxford University Press (OUP)","issue":"6","license":[{"start":{"date-parts":[[2026,2,3]],"date-time":"2026-02-03T00:00:00Z","timestamp":1770076800000},"content-version":"vor","delay-in-days":1920,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"},{"start":{"date-parts":[[2020,11,4]],"date-time":"2020-11-04T00:00:00Z","timestamp":1604448000000},"content-version":"vor","delay-in-days":3,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"funder":[{"name":"North Carolina State University Vector Borne Disease Diagnostic Laboratory"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2020,11,1]]},"abstract":"Abstract<\/jats:title>\n \n Background<\/jats:title>\n Atovaquone and azithromycin (A&A) with supportive care improve survival rates in cats with cytauxzoonosis. Resistance to atovaquone via parasite cytochrome b gene (cytb) mutations occurs in other Apicomplexan protozoans but is not described in Cytauxzoon felis.<\/jats:p>\n <\/jats:sec>\n \n Objective<\/jats:title>\n To serially characterize the C. felis cytb sequences from a cat that remained persistently infected after A&A treatment.<\/jats:p>\n <\/jats:sec>\n \n Animal<\/jats:title>\n A cat with naturally occurring C. felis infection.<\/jats:p>\n <\/jats:sec>\n \n Methods<\/jats:title>\n Case report of the anemic cat persistently infected with C. felis before, during and after A&A treatment. Cytauxzoon felis cytb genes were amplified and sequenced before, during and after A&A treatment.<\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n Cytauxzoon felis was detected before, during and after A&A treatment including samples collected 570\u2009days after treatment. After A&A treatment, the cat's anemia improved slightly. Cytb sequencing revealed only wild-type cytb methionine (M128) in samples collected before treatment. In samples collected after treatment, the cytb coded for isoleucine (M128I) and valine (M128I) at 2- and 4-months after treatment. These M128I and M128V mutations persisted even after a repeat treatment course with a higher dose atovaquone combined with the standard dose of azithromycin.<\/jats:p>\n <\/jats:sec>\n \n Conclusions and Clinical Importance<\/jats:title>\n This report documents C. felis atovaquone resistance associated with M128 cytb mutations. This study suggests parasites with mutations of cytb M128 can be selected and impart resistance to A&A treatment even with higher atovaquone dosing.<\/jats:p>\n <\/jats:sec>","DOI":"10.1111\/jvim.15935","type":"journal-article","created":{"date-parts":[[2020,11,4]],"date-time":"2020-11-04T15:53:47Z","timestamp":1604505227000},"page":"2432-2437","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Cytauxzoon felis<\/i>\n cytochrome\n b<\/i>\n gene mutation associated with atovaquone and azithromycin treatment"],"prefix":"10.1093","volume":"34","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1553-1026","authenticated-orcid":false,"given":"Ashley N.","family":"Hartley","sequence":"first","affiliation":[{"name":"College of Veterinary Medicine, North Carolina State University Department of Clinical Sciences, , Raleigh, North Carolina,","place":["USA"]},{"name":"College of Veterinary Medicine, University of Tennessee Department of Small Animal Clinical Sciences, , Knoxville, Tennessee,","place":["USA"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Henry S.","family":"Marr","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, North Carolina State University Department of Clinical Sciences, , Raleigh, North Carolina,","place":["USA"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2617-2252","authenticated-orcid":false,"given":"Adam J.","family":"Birkenheuer","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, North Carolina State University Department of Clinical Sciences, , Raleigh, North 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