Prevalence of antibodies to Toxoplasma gondii in dogs from northeastern Portugal.

Prevalence of antibodies to Toxoplasma gondii was investigated in 673 domestic dogs from northeastern Portugal, using the modified agglutination test (MAT) with 1 : 20 as cutoff for seropositivity; antibodies were found in 256 dogs (38.0%). Differences between seroprevalence levels in males (36.7%) and females (41.8%) and between pure-breed (42.1%) and mixed-breed dogs (35.2%) were not statistically significant. Multiple logistic regression analysis identified age above 12 mo (odds ratio [OR]  =  4.0), chance of eating birds or small mammals (OR  =  4.0), housing exclusively outdoors (OR  =  1.5), home-cooked meals (OR  =  3.0), and eating raw meat or viscera (OR  =  7.7) as risk factors for the canine T. gondii infection. Some control measures are suggested based on these findings.