Efficacy of a 3C-like protease inhibitor in treating various forms of acquired feline infectious peritonitis

Pedersen, Niels C; Kim, Yunjeong; Liu, Hongwei; Galasiti Kankanamalage, Anushka C; Eckstrand, Chrissy; Groutas, William C; Bannasch, Michael; Meadows, Juliana M; Chang, Kyeong-Ok

The diagnosis of FIP was confirmed at the time of entry into the study based on signalment, clinical history, examination of prior laboratory test results, physical examination and repeat of basic blood and effusion analyses. Manual palpation of the abdomen was usually sufficient to identify ascites, enlarged mesenteric lymph nodes, enlargement of the cecum and associated ileo-cecal-colic lymph nodes, masses in the kidneys and colonic infiltration. Manual palpation was augmented, when necessary, by ultrasonography. Eyes were examined initially with directed light for any abnormalities in the retina, precipitates in anterior chamber or on the back of the cornea, and aqueous flare. The presence of ocular disease was confirmed when in question by complete ophthalmoscopic examination conducted by the ophthalmology service of the Veterinary Medical Teaching Hospital (VMTH), UC Davis. The presence of FIPV was further confirmed by qRT-PCR, 6 either from abdominal or thoracic effusions taken at the time of admission or at the time of necropsy. Sequencing of the FIPV protease gene was carried out on cats that relapsed while on therapy, to determine whether potential mutation conferring drug resistance had occurred. 5, 6 The diagnosis of dry-to-wet FIP in three cats (CT03, CT10 and CT14) was based on diffuse enlargement of the colon and histories of loose stools, blood and mucus in the stool, straining to defecate and small-caliber stools prior to occurrence of abdominal effusions. Colonic FIP has been described as a specific variant form of non-effusive FIP. 9 Dry-to-wet FIP was also suspected in cats CT01, CT02 and CT12, owing to a stunting of growth that preceded the appearance of abdominal effusions by many weeks.