Western Carolina University

About La Crosse Encephalitis
Every summer, local children (typically less than 16 years old) end up in hospital intensive care units suffering from La Crosse encephalitis, a viral infection and inflammation of the brain. The cause of this illness: the bite of mosquito infected with La Crosse virus.  Although death is rare (Case Fatality Rate <1%), the social and economic burden of the disease is high, especially when life-long disabilities result from the infection (Utz et al, 2003). In general, the annual number of recognized La Crosse encephalitis cases in western North Carolina appears to be increasing. However, these recognized cases represent the “tip of the iceberg” in terms of virus transmission.  For every one recognized case of La Crosse encephalitis, it is likely that many, many more individuals were exposed to the virus through a mosquito bite. In addition, it is likely that a substantial number of clinically apparent La Crosse virus infections that occur each year in NC are not diagnosed.