CLINICAL AND SEROLOGIC EVALUATION OF CATS WITH CRYPTOCOCCOSIS

Objective - To evaluate the long-term clinical outcomes and serologic changes in cryptococcal antigen and antibody titers in cats with confi rmed Cryptococcus neoformans infection. Design - Prospective case seri es. Animals - 47 cats with cryptococcosis. Procedure - Cats included i n this study were determined to have cryptococcosis on the basis of id entification of C neoformans on histologic or cytologic examination, i solation of C neoformans in culture, or positive serologic test result s for cryptococcal antigens. Information concerning the signalment, hi story, physical examination findings, FeLV and feline immunodeficiency virus status, serologic testing, treatment, and outcome for each cat was requested on a survey form. Follow-up measurements of serum crypto coccal antigen and antibody titers were requested for all surviving ca ts. Results - Signalment and clinical signs of cats with cryptococcosi s reported here were consistent with previous reports. Treatment consi sted primarily of azole antifungal drugs. Ail cats were seronegative f or cryptococcal antibody titers, whether tested initially or at follow -up examination. Ail but 1 cat tested were seropositive for cryptococc al antigens when initially tested. Cats with and without clinical sign s of C neoformans infection were seropositive for cryptococcal antigen s months to years after initial diagnosis of cryptococcosis.Clinical I mplications - The results of this study indicate that serum titers to cryptococcal antigens in cats can persist with or without clinical sig ns for months to years after an initial diagnosis of cryptococcosis is made. Repeated evaluation of serum cryptococcal antigen titers is adv ised during the treatment of cats to monitor progress, evaluate progno sis, and guide cessation of treatment.