Emergence and re-emergence of viral diseases of the central nervous system

https://doi.org/10.1016/j.pneurobio.2009.12.003Get rights and content

Abstract

Neurologic disease is a major cause of disability in resource-poor countries and a substantial portion of this disease is due to infections of the CNS. A wide variety of emerging and re-emerging viruses contribute to this disease burden. New emerging infections are commonly due to RNA viruses that have expanded their geographic range, spread from animal reservoirs or acquired new neurovirulence properties. Mosquito-borne viruses with expanding ranges include West Nile virus, Japanese encephalitis virus and Chikungunya virus. Zoonotic viruses that have recently crossed into humans to cause neurologic disease include the bat henipaviruses Nipah and Hendra, as well as the primate-derived human immunodeficiency virus. Viruses adapt to new hosts, or to cause more severe disease, by changing their genomes through reassortment (e.g. influenza virus), mutation (essentially all RNA viruses) and recombination (e.g. vaccine strains of poliovirus). Viruses that appear to have recently become more neurovirulent include West Nile virus, enterovirus 71 and possibly Chikungunya virus. In addition to these newer challenges, rabies, polio and measles all remain important causes of neurologic disease despite good vaccines and global efforts toward control. Control of human rabies depends on elimination of rabies in domestic dogs through regular vaccination. Poliovirus eradication is challenged by the ability of the live attenuated vaccine strains to revert to virulence during the prolonged period of gastrointestinal replication. Measles elimination depends on delivery of two doses of live virus vaccine to a high enough proportion of the population to maintain herd immunity for this highly infectious virus.

Abbreviations

CHIKV
Chikungunya virus
CNS
central nervous system
DALY
disability adjusted life year
EV71
enterovirus 71
HIV
human immunodeficiency virus
JEV
Japanese encephalitis virus
SSPE
subacute sclerosing panencephalitis
WNV
West Nile virus

Keywords

Viral encephalitis
Measles
Polio
Subacute sclerosing panencephalitis
Chikungunya
West Nile virus
Rabies
Japanese encephalitis

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