Diagnostic Testing for Encephalitis, Part II

Encephalitis is characterized by both its pleomorphic clinical presentation and its diagnostic challenges. Fever, headache, and alteration of consciousness are classically present, however, the diversity of neurological symptoms can make it difficult to distinguish encephalitis from other infectious and non-infectious central nervous system conditions. Identification of a specific pathogen has important therapeutic and prognostic implications for an individual patient and has broader public health significance in potentially identifying a need for prophylaxis of contacts or environmental control of arthropod vectors. In Part I of this article, the basic features of encephalitis and aspects of diagnostic testing for encephalitis caused by herpes simplex virus, the non-simplex Herpesviridae, enteroviruses, and specific agents causing tick-borne diseases were discussed. In Part II of this series, additional agents causing encephalitis in North America are discussed in terms of the issues in diagnostic testing; these agents include West Nile virus, other arthropod-borne viruses, rabies virus, Bartonella spp., Tropheryma whipplei, Mycoplasma pneumoniae, and Treponema pallidum.