International Journal of Molecular Veterinary Research, 2024, Vol.14, No.5, 219-226 http://animalscipublisher.com/index.php/ijmvr 222 pradofloxacin and doxycycline in resolving clinical signs and achieving negative PCR results for Bartonella henselae, suggesting a potential therapeutic approach for managing such infections. In summary, subclinical infections in cats, particularly those caused byBartonella henselae, can lead to significant immune alterations, including changes in immune cell populations and cytokine imbalances. These infections can persist without obvious symptoms, yet they have the potential to cause chronic immune activation and related health issues. Figure 2 Surface expression of BadA in various B. henselae strains (immunofluorescence microscopy) (Adopted from Thibau et al., 2022) Image caption: Surface expression of BadA was analysed via immunofluorescence microscopy using specific anti-BadA IgG antibodies (green). Bacterial DNA was counterstained using DAPI (blue). The illustrated B. henselae strains are (A) Marseille, (B) Marseille 1BadA-T, (C) Marseille 1BadA-D, (D) ATCC49882T var-1, (E) ATCC49882T var-2, (F) Berlin-I, (G) G-5436, (H) 88-64 Oklahoma, (I) FR96/BK38, and (J) FR96/BK3. Expression is observed for strains Marseille, ATCC49882T var-2, G-5436, 88-64 Oklahoma, FR96/BK38, and FR96/BK3, detected by the characteristic green halo. Strains ATCC49882T var-1 and Berlin-I do not express BadA, nor do the negative control strains Marseille 1BadA-T and Marseille 1BadA-D. Scale bar: 5 µm (Adopted from Thibau et al., 2022) 5 Clinical and Subclinical Implications of Immune Dysregulation 5.1 Immune suppression and increased infection susceptibility Subclinical bacterial infections in cats can lead to immune suppression, making them more susceptible to other infections. The immune system's ability to respond to pathogens is compromised, as seen in studies where immune checkpoints like TIGIT are upregulated, leading to reduced immune function and increased vulnerability to infections (Souza-Fonseca-Guimaraes et al., 2023). Additionally, dysbiosis in the microbiota, often caused by antibiotic use or dietary changes, can further impair immune responses, increasing the risk of chronic diseases and infections (Tizard et al. 2017). 5.2 Autoimmune reactions induced by subclinical infections Subclinical infections can also trigger autoimmune reactions in cats. The immune system may mistakenly target the body's own cells, leading to autoimmune diseases. This phenomenon is partly due to the dysregulation of immune responses, where the balance between immune activation and suppression is disrupted. For instance, changes in the microbiota can influence the development of autoimmune diseases by altering immune responses (Tizard et al. 2017). Moreover, the presence of persistent bacterial infections can mimic self-antigens, potentially leading to autoimmunity (Souza-Fonseca-Guimaraes et al., 2023). 5.3 Chronic inflammation and its impact on feline health Chronic inflammation is a significant consequence of immune dysregulation caused by subclinical infections. Persistent inflammatory responses can lead to tissue damage and contribute to the development of chronic diseases. In cats, chronic inflammation has been linked to conditions such as atopic dermatitis and respiratory allergies (Tizard et al. 2017). Furthermore, the presence of reactive oxygen species (ROS) as a response to
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