Clinical ocular toxoplasmosis in neonatal kittens

Objective To describe ocular findings in kittens with congenital or early neonatal infection by Toxoplasma gondii and to determine if there are detectable differences in disease caused by three strains. Animals studied Six adult female cats and the offspring from seven litters. Methods Four kittens from uninfected specific pathogen‐free (SPF) queens and 21 kittens from SPF queens inoculated at various times late in gestation with Mozart, Maggie, or ME‐49 strain of T. gondii were used. Ocular examinations were performed on queens prior to and after delivery, and on kittens weekly to bi‐weekly for up to 27 weeks. Whole blood for serology was collected from all kittens at 5½ to 8 weeks of age and again at 12 weeks of age or later. Results No kittens from noninfected queens developed ocular lesions or antibody to T. gondii. Three of the 24 kittens from infected queens died or were euthanized early in the study. Chorioretinitis was detected in 15 of 21 living kittens from infected queens. Two developed concurrent anterior uveitis that resolved within 1 week. Posterior segment lesions varied ophthalmoscopically between strains. Of 21 kittens from T. gondii‐infected queens, six developed positive antibody titers to T. gondii during the study. All seropositive kittens were born to queens infected with Mozart strain of T. gondii. Conclusion Results of this study suggest that ocular toxoplasmosis can occur without other evidence of clinical illness in kittens infected in utero or in the neonatal period, and that T. gondii strains may have varying degrees of ocular pathogenicity in cats.