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 Toxoplasma gondii. 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 T. gondii infection in cats. Feline sera and surplus EDTA anticoagulated blood samples, for which AB blood group system phenotypes had been determined, were analyzed for T. gondii antibodies (ELISA, cut-off S/P% ≥50% and IFAT, cut-off ≥1:64) and DNA (nested and real-time PCR). T. gondii 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 (p < 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 T. gondii: 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 T. gondii infection. FIV seropositive cats had a higher risk (OR = 3.1, p = 0.0043) of testing T. gondii positive. This study did not find an association between T. gondii 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 Toxoplasma gondii infection in cats. These findings contribute to our knowledge of the role of blood types in disease susceptibility in cats.