The AB Blood Group System Phenotype Does Not Play a Role in Toxoplasma gondii Infection in Cats

Previous studies have evaluated the association between different blood groups and human infection with <i>Toxoplasma gondii</i>. No similar studies exist in cats. The objective of this study was to evaluate the role of some risk or protective factors, including the AB blood type system phenotypes, in <i>T. gondii</i> infection in cats. Feline sera and surplus EDTA anticoagulated blood samples, for which AB blood group system phenotypes had been determined, were analyzed for <i>T. gondii</i> antibodies (ELISA, cut-off S/P% ≥ 50% and IFAT, cut-off ≥ 1:64) and DNA (nested and real-time PCR). <i>T. gondii</i> status and the characteristics of signalment (gender, breed, and age), lifestyle (stray, shelter, privately-owned), origin (Northern or Southern Italy), and retroviral infection serostatus of the population were evaluated using the Chi-square test, with calculation of the Odds Ratio (OR) in cases of statistically significant association (<i>p</i> < 0.05). A total of 199 samples were analyzed, of which 178 were phenotype A, 15 were phenotype B, and 6 were phenotype AB. Of these, 57/199 (28.6%) were positive for <i>T. gondii</i>: 5 were positive at PCR, 33 at ELISA, and 19 at IFAT. Of the 57 positive cats, 52/57 were phenotype A, 3/57 phenotype B, and 2/57 phenotype AB, with no significant association with <i>T. gondii</i> infection. FIV seropositive cats had a higher risk (OR = 3.1, <i>p</i> = 0.0043) of testing <i>T. gondii</i> positive. This study did not find an association between <i>T. gondii</i> infection and the feline blood types investigated; therefore, based on our results, AB blood group system phenotypes do not seem to play a role in <i>Toxoplasma gondii</i> infection in cats. These findings contribute to our knowledge of the role of blood types in disease susceptibility in cats.