Emerging viral infections.

PURPOSE OF REVIEW: This review highlights research and development in the field of emerging viral causes of encephalitis over the past year.

RECENT FINDINGS: There is new evidence for the presence of henipaviruses in African bats. There have also been promising advances in vaccine and neutralizing antibody research against Hendra and Nipah viruses. West Nile virus continues to cause large outbreaks in the United States, and long-term sequelae of the virus are increasingly appreciated. There is exciting new research regarding the variable susceptibility of different brain regions to neurotropic virus infection. Another cluster of solid organ transplant recipients developed encephalitis from organ donor-acquired lymphocytic choriomeningitis virus. The global epidemiology of Japanese encephalitis virus has been further clarified. Evidence continues to accumulate for the central nervous system involvement of dengue virus, and the recent deadly outbreak of enterovirus 71 in Cambodian children is discussed.

SUMMARY: In response to complex ecological and societal dynamics, the worldwide epidemiology of viral encephalitis continues to evolve in surprising ways. The articles highlighted here include new research on virus epidemiology and spread, new outbreaks as well as progress in the development of vaccines and therapeutics.