1. Sue Johnston DNP, RN, FNP-BC 2. Infections of the central nervous system(CNS) consist mainly of meningitis andencephalitis and are caused by a variety ofpathologic microorganisms. High morbidity and mortality rates ofbacterial meningitis make diagnosis and earlytreatment a high priority. Bacterial meningitis most common inchildren < 2 with peak incidence at 3 8months. Second peak incidence after 60 years of age. US annual incidence 2-5/100,000 persons 3. Encephalitis is primarily caused by herpesviruses (40%), arboviruses (insecttransmission), and enteroviruses. Peak incidence in the late summer months. Meningitis defined as either aseptic or septic,depending on identification of bacteria onthe Gram stain or culture. Aseptic meningitis is caused primarily byenteroviruses. Amebic meningoencephalitis is rare butalmost always fatal. 4. Amebicmeningioencephalitis-cont Caused by infection with Naegleria fowleri, free- living ameba found in freshwater environments. Infection results from water containing N. fowleri entering the nose, followed by migration of the amebae to the brain via the olfactory nerve. 2007, six cases of PAM in the United States were reported to CDC; all six patients died. cases, which occurred in three southern tier states (Arizona, Florida, and Texas) during June-- September