In a 2-part review, a neuroinfectious disease specialist at the University of Colorado Denver Health Sciences Center and Veterans Medical Center describes emerging viral infections as diseases that infect new hosts, spread into new geographic areas, alter their pathogenesis, or are caused by agents not recognized as pathogenic. Of 1415 species of infectious organisms known to be pathogenic in humans, 175 are considered to be emerging, with viruses and prions accounting for 77 (44%) of the total, and 80% having a primary nonhuman animal source (zoonotic). Animals, particularly wild animals, are significant risk factors for emerging infectious diseases (EIDs), and 40% of viral zoonotic EIDs are vectorborne. Exposure to mosquitoes and common arthropod vectors is another major factor in disease emergence. Host factors also play a key role in EIDs, an increased susceptibility resulting from AIDS, immunosuppression with cancer chemotherapy, organ transplant-associated, and drugs used to treat autoimmune and immune-mediated disorders. Viral EIDs cause severe neurological symptoms such as encephalitis in 39% of cases, and occasionally in an additional 10%. The review of various viruses includes 76 references. [1]

COMMENT. Millichap JJ and Epstein LG in their recent publication, neuroinfectious disease as an emerging subspecialty in neurology [2], discuss career prospects for neurologists interested in the field. Accredited fellowships are in the developing stage, but non-accredited training is available at several institutions. Close identification with a mentor in neuro-ID and collaboration with medicine or pediatrics-based ID specialists are essential requirements. Important roles for pediatric neurology ID subspecialists include consultant to an ID service for acute CNS infections, and diagnosis and management of chronic neuroinfectious disorders, including postinfectious epilepsy. Development of new antimicrobial and anti-inflammatory agents is an area of future research, especially in the management of emerging viral infections. Dedicated textbooks and reviews on neuro-ID cited by Millichap and Epstein include: [3, 4, 5]