CLINICAL AND LABORATORY FINDINGS IN CHRONIC CONJUNCTIVITIS IN CATS - 91 CASES (1983-1991)

Clinical findings and laboratory test results from 91 cats with chroni c conjunctivitis were studied to determine the causes of the disease a nd the sensitivity of diagnostic procedures used, and to identify corr elations between results of various diagnostic procedures and clinical or signalment variations. Mean age of affected cats was 2.9 +/- 2.7 y ears (+/- SD), with a range from 1 month to 11 years. Conjunctivitis w as more likely to be bilateral (56 cats) than unilateral (35 cats). In cats tested for FeLV or feline immunodeficiency virus infection, 15 a nd 8.5%, respectively, of the results were positive, compared with 4 a nd 2.6% for the general hospital population. Culturing or immunofluore scent assay (IFA) for feline herpesvirus 1 (FHV-1) and Chlamydia psitt aci IFA resulted in identification of pathogens (positive test results ) in 19% (FHV-1) and 18% (C psittaci) of tested cats. For FHV-1, cultu ring was more sensitive than was IFA, yielding positive results in 19 vs 8.8% of cases. In only 1 cat were FHV-1 and chlamydiae recovered. T he probability of positive test results for FHV-1 or chlamydiae was un related to concurrent corneal disease, unilateral vs bilateral involve ment, or age. Cause Of conjunctivitis could not be definitively determ ined in the remaining 35 cases tested for both agents. Bacterial speci es considered to be potentially pathogenic were isolated from conjunct ival sac specimens in only 1 of 38 attempts. Cytologic changes conside red compatible with chlamydial or FHV-1 infection (intracytoplasmic in clusions or multinucleated epithelial cells, respectively) were found in 8 and 5 cases, respectively. In only 4 of these cases, however, was the cytologic impression supported by a concurrently positive result on antigen-detection testing. This study revealed that routinely used diagnostic procedures were not able to confirm an etiologic diagnosis in most cats with chronic conjunctivitis.