Toxoplasma gondii in Romanian household cats: evaluation of serological tests, epidemiology and risk factors.

Felines are the key species in the epidemiology of Toxoplasma gondii infection, as they are the definitive host of the parasite and are the only species that can shed resistant oocysts in the environment. Different assays are in use for the detection of antibodies against T. gondii in cats. However, assay validation studies are limited. For that reason it was our aim to first evaluate 6 serological tests (one commercial and 2 in-house ELISAs, ImmunoComb, IFAT and MAT) for antibodies (IgG) against T. gondii in cats by Bayesian modeling. Factors associated with seropositivity were evaluated by bivariable and multivariable methods. The test evaluation indicated the commercial ELISA had the highest Youden Index. The estimated sensitivity ranged between 95.7% and 97.1% and the specificity between 97.3% and 97.6%. Using this commercial ELISA 111 out of 236 cats (47%) were positive for T. gondii antibodies. Two peaks in the percentage of strong positive samples (S/P≥200) were observed, around 10-months-old and 8-years-old. In bivariable analysis the seroprevalence was significantly higher in adult cats, cats with mixed diet, with outdoor access, in cats from a rural area and in cats from centre and north-western Romania. Adult age (adults: OR 6.98; 95% CI: 2.02-24.14 and geriatrics (cats older than 10-years): OR 12.01; 95% CI: 1.60-90.15) and outdoor access (OR 6.38; 95% CI: 2.32-17.53) remained significant risk factors in the multivariable logistic regression analysis. Our results suggest that T. gondii infection is common in household cats in Romania, and especially in those with outdoor access.