“Cat scratch disease (CSD) is a bacterial disease caused by Bartonella henselae and it is mainly characterized by self-limiting lymphadenopathy in the draining site of a cat scratch or bite. We report a patient with history of fever, swelling lymph nodes,
vasculitic-like skin lesions, and positivity of Bartonella serology initially considered as expression of a disimmune disease.” -https://www.ncbi.nlm.nih.gov/pubmed/22924138
It is the height of naïveté to believe in causation – it is impossible for a cat scratch, mosquito bite or whatever to have one and only one type of harmful substance. The different clinical courses of cat scratch disease victims show this – not only are they different, but each scratch delivers different doses of different harmful substances. Bartonella is but one of these substances and it may not even be the most harmful in some cases.