Molecular Detection of Anaplasma phagocytophilum in Cats in Europe and Associated Risk Factors

Simple Summary: Although Anaplasma (A.) phagocytophilum infection in cats is considered to be less frequent compared with dogs, there is evidence indicating that the risk of the infection in cats might be underestimated. The study aimed to find out if infections in cats are underestimated and to discover which factors increase the risk of infection. Blood samples of 1015 cats across Europe were tested for A. phagocytophilum DNA from 2017 to 2022. The number of samples sent for testing increased over the 6 years. Anaplasma phagocytophilum DNA was found in 76 out of 1015 cats (7.5%). Infections were more common in Northern Europe than in Central or Southern Europe. During summer, the number of positive samples was significantly higher compared with winter (p = 0.047). The risk for A. phagocytophilum infection in cats should not be underestimated, especially in Northern Europe. Preventing tick bites is essential for cats' health all over Europe, not just in the Mediterranean regions. Infections with Anaplasma (A.) phagocytophilum in cats seem to be rare. The study aimed to determine whether infections in cats are underestimated and to identify the risk factors for infection. Blood samples of 1015 cats across Europe (2017-2022), sent to IDEXX Laboratories, Germany, were tested for A. phagocytophilum DNA. The influence of the cats' origin on A. phagocytophilum infection was assessed by univariable analysis, while multivariable logistic regression evaluated associations with the cats' sex and age, and the years, and seasonality of the samples' submission. Furthermore, univariable linear regression was used to determine patterns in PCR orders. The number of submitted samples increased significantly during the 6 years (p = 0.042). Anaplasma phagocytophilum DNA was detected in 76/1015 of cats (7.5%, 95% CI 6.0-9.3%). Infections were significantly more common in Northern compared to Central (p < 0.001, OR: 8.70) and Southern Europe (p < 0.001, OR: 39.94). A significantly higher likelihood for infections during the summer compared with winter (p = 0.047, OR: 3.13) was found. Bacteremia with A. phagocytophilum in European cats is not uncommon. Anaplasma phagocytophilum infection should be considered an important risk, particularly in Northern Europe. Effective tick prevention is crucial for managing feline health across Europe, not just in the Mediterranean region.