First identification of a single amino acid change in the spike protein region of feline coronavirus detected from a coronavirus-associated cutaneous nodule in a cat

Osumi, Takafumi; Mitsui, Ikki; Leutenegger, Christian M; Okabe, Ryo; Ide, Kaori; Nishifuji, Koji

A spayed female Singapura cat aged 2 years and 8 months that was kept indoors presented with a 6 month history of a non-pruritic erythematous nodule on the upper lip. The lesion was originally noticed by the owners as small erythematous nodules, which had become enlarged and partially ulcerated in the previous 6 months. The cat also had a history of sneezing and nasal discharge from 3 months of age. The cat had received vaccinations against feline herpesvirus (FHV), feline calicivirus (FCV), and feline parvovirus three times each; the primary vaccination was administered at 2 months of age, and booster vaccinations were administered at the age of 3 months and at 1 year and 4 months. Beginning at the age of 2 years and 5 months, unilateral stomatitis in the right mandible became evident. Neither the owner nor the referring veterinarian noticed oral pain in the cat. Although the cat did not show decreased appetite, the cat had lost approximately 0.5 kg of body weight in the previous 6 months. The cat was kept with another Singapura cat that did not show similar clinical signs. Neither of the two cats had received flea-prevention treatments.