Infection in the Nervous System

Infections of the nervous system can be caused by viruses, bacteria, fungi, protozoa or prions. Bacterial meningitis is caused by a primary purulent infection within the subarachnoid space that leads to acute inflammation of the meninges. Bacterial infection reaches the central nervous system either by direct invasion, haematogenous spread or embolisation of infected thrombi. Focal infection causes abscess formation within or immediately adjacent to the brain or spinal cord. Cerebral abscess is a focal suppurative infection occurring within the cerebral parenchyma. Brucellosis is a zoonotic infection caused by Gram-negative coccobacilli, Brucella melitensis , Brucella abortis and Brucella suis . It is a granulomatous disease, either acute or indolent in character. Syphilis is increasing in prevalence in the UK, particularly among homosexual men with HIV. It is a chronic systemic infection caused by the spirochaete Treponema pallidum ssp. pallidum . Diphtheria is caused by the diphtheria toxin produced by some strains of Corynebacterium , anaerobic Gram-positive bacteria.