Common Viral Infection in Infants May Persist Long-term in the CNS

A new study suggests that coxsackievirus, a significant human pathogen that commonly infects the central nervous system of newborns, may persist in the body as a low-level, long-term infection causing ongoing inflammatory lesions. This discovery disputes previous beliefs that while acute, coxsackievirus is also self-limiting. The researchers report their findings in the September 2009 issue of the Journal of Virology.

Coxsackievirus is a commonly occurring childhood infection that afflicts the central nervous system. It is often diagnosed in newborns and can lead to complications such as meningitis, encephalitis, and death. Prior research indicates that infection of the central nervous system at an early age may result in severe physical and intellectual disabilities, deficiencies in scholastic performance, and even the development of neurological disorders such as schizophrenia later in life. A large percentage of polio victims are now experiencing new symptoms, known as post-polio syndrome, some 50 years after the primary infection suggesting we may be underestimating the lasting effects of childhood infections on the central nervous system.

In a previous study the researchers utilized a neonatal mouse model of coxsackievirus B3 (CVB3) to determine that stem cells in the central nervous system were preferentially targeted by the virus. The later stages of infection were the focus of this study in which the researchers examined the ensuing inflammatory response and lesions remaining in the adult central nervous systems of surviving mice from the previous model. Results showed high levels of interferons and chemokines up to 10 days post-infection as well as chronic inflammation and lesions in the brains of surviving mice up to nine months post-infection. Additionally, CVB3 RNA was detected in the central nervous system at high abundance up to three months post-infection.

"These data suggest that CVB3 may persist in the CNS as a low-level, noncytolytic infection, causing ongoing inflammatory lesions," say the researchers. "Thus, the effects of a relatively common infection during the neonatal period may be long lasting, and the prognosis for newborn infants recovering from acute infection should be re-explored."