Bartonella is a bacteria that invades red blood cells and blood vessel lining. Inside these cells, it evades the immune system response, leading to persistent infection. Bartonellosis is one of Lyme’s most serious coinfections, producing symptoms that include headache, fatigue, swollen glands, and a streaked rash in the early stages. Neurological symptoms are common, including encephalopathy, a form of brain damage or disease that may lead to seizures. Cognitive dysfunction and central nervous system lesions sometimes occur. Bartonella is the cause of more serious conditions, including cat scratch disease, Carrion’s disease, and trench fever.