{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,23]],"date-time":"2026-03-23T13:19:34Z","timestamp":1774271974215,"version":"3.50.1"},"reference-count":36,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2026,3,21]],"date-time":"2026-03-21T00:00:00Z","timestamp":1774051200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pathogens"],"abstract":"<jats:p>Background: There is limited information about treatment success and outcomes in retrovirus-positive cats diagnosed with feline infectious peritonitis (FIP). Methods: A survey was distributed to caretakers of cats with feline leukemia virus (FeLV) and\/or feline immunodeficiency virus (FIV) that were treated with GS-441524 for presumptive effusive FIP based on survey responses. Results: Cats with FIV developed FIP at an older age and longer after retrovirus infection than cats with FeLV. The average starting dosage (7 mg\/kg\/d) was increased in 65% of cats, and treatment was extended in 35%. Three cats relapsed (18%). There was a 94% (16\/17) twelve-week survival rate and 82% (14\/17) one-year survival rate. Seven cats were alive at follow-up, a median of 1306 days (range 983\u20132069) after FIP diagnosis, but many cats succumbed to neoplasia. Conclusions: Treatment success for retrovirus-positive cats with presumptive FIP was similar to previously reported outcomes for FIP alone. This could support current evidence of successful antiviral therapy for similar populations, if noncurrent, unstandardized protocols and unlicensed product use are considered. Additional studies are needed to determine ideal protocols for rapid resolution of FIP, good long-term survival, and limited relapse in retrovirus-positive cats, and the impact of the FeLV proviral load.<\/jats:p>","DOI":"10.3390\/pathogens15030337","type":"journal-article","created":{"date-parts":[[2026,3,23]],"date-time":"2026-03-23T11:59:36Z","timestamp":1774267176000},"page":"337","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Clinical Features and Outcomes of Treatment for Effusive Feline Infectious Peritonitis with GS-441524 in Seventeen Retrovirus-Positive Cats"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9424-0731","authenticated-orcid":false,"given":"Marilize","family":"Van der Walt","sequence":"first","affiliation":[{"name":"Internal Medicine Department, MedVet Medical & Cancer Center for Pets, Columbus, OH 43085, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sarah E.","family":"Jones","sequence":"additional","affiliation":[{"name":"Internal Medicine Department, MedVet Medical & Cancer Center for Pets, Columbus, OH 43085, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4849-288X","authenticated-orcid":false,"given":"Julie K.","family":"Levy","sequence":"additional","affiliation":[{"name":"Shelter Medicine Program, College of Veterinary Medicine, University of Florida, Gainesville, FL 32608, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Emma","family":"Hart","sequence":"additional","affiliation":[{"name":"Faithful Friends Veterinary Clinic, Dublin, OH 43017, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rosa","family":"Negash","sequence":"additional","affiliation":[{"name":"Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5146-7706","authenticated-orcid":false,"given":"Wendy M.","family":"Novicoff","sequence":"additional","affiliation":[{"name":"Departments of Orthopaedic Surgery and Public Health Sciences, School of Medicine, University of Virginia, Charlottesville, VA 22901, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nicole","family":"Jacque","sequence":"additional","affiliation":[{"name":"Independent Researcher, San Jose, CA 95123, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Samantha J. M.","family":"Evans","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1089","DOI":"10.3201\/eid1807.120143","article-title":"Spike Protein Fusion Peptide and Feline Coronavirus Virulence","volume":"18","author":"Chang","year":"2012","journal-title":"Emerg. Infect. Dis."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"14122","DOI":"10.1128\/JVI.79.22.14122-14130.2005","article-title":"Acquisition of Macrophage Tropism during the Pathogenesis of Feline Infectious Peritonitis Is Determined by Mutations in the Feline Coronavirus Spike Protein","volume":"79","author":"Rottier","year":"2005","journal-title":"J. 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