Neurologic Manifestations of Tick-Borne Diseases Transmitted by Deer Ticks (Ixodes scapularis) in the USA

Purpose of Review This article aims to review the relevant updates in pathogenesis, diagnostics, clinical manifestations, and treatments of tick-borne diseases involving the nervous system, with special emphasis on emerging viral and bacterial infections transmitted by deer ticks (Ixodes scapularis).Recent Findings Neuroborreliosis includes a wide array of peripheral and/or central nervous system syndromes, of which diagnosis depends on a combination of clinical gestalt, serum serologic testing, and CSF cellular and serologic analysis. Powassan virus may cause life-threatening neuroinvasive disease and diagnosis that is based on CSF serology with treatment being largely supportive. Neurologic manifestations of anaplasmosis and babesiosis are rare but have been documented in case reports. Diagnosis is dependent on serum molecular and microscopic and serologic testing, and the pathophysiologic mechanisms of these neurologic syndromes are not fully understood. Borrelia miyamotoi is an emerging pathogen and, in immunocompromised patients, can cause severe meningoencephalitis.Summary Ixodes scapularis-borne infections such as Lyme disease, anaplasmosis, babesiosis, Powassan virus, and Borrelia miyamotoi disease can have significant neurologic manifestations. Due to the potential for poor outcomes, physicians must have a working knowledge of these pathogens, and a high index of suspicion is required to screen for these diseases in patients with the correct risk factors. Future research will help realize the full range of neurologic manifestations of these pathogens and also clarify their underlying pathophysiologic mechanisms, which will aid in developing new methods of diagnosis and treatment.