**2.3 Acute stroke and infectious diseases**

Various infections may cause cerebrovascular complications, mainly due to involvement of the CNS vasculature by the pathogen itself usually with an inflammatory reaction of the immune system. The activation of pro-thrombotic mechanisms as a result of infection, and cardiac embolization in case of an infective endocarditis are other pathogenic mechanisms in the development of stroke [13]. Cerebral infarctions can be seen in viral infections such as HIV and VZV. The underlying mechanism in HIV infection was thought to be direct vasculopathy and hypercoagulable state [14, 15]. Syphilitic arteritis and inflammatory vasculopathy in Lyme's disease, which is caused by *Borrelia burgdorferi*, are good examples for spirochetal infections that cause cerebral infarctions [16, 17]. *Hemophilus influenzae, Neisseria meningitidis*, and *Streptococcus pneumoniae*—the pathogens causing pyogenic meningitis may lead to cerebral infarctions as a result of disturbance of larger arteries at the skull base by a purulent exudate, and arterial spasm in response to inflammation [18]. Infective endocarditis is a well-documented cause of strokes due to occlusion of intracranial arteries by an embolic material derived from vegetations [19].
