Neurotropic viruses and cerebral palsy: population based case-control study.

OBJECTIVE To investigate the association between cerebral palsy and direct evidence for perinatal exposure to neurotropic viruses. DESIGN Population based case-control study. SETTING Adelaide Women's and Children's Hospital Research Laboratory. PARTICIPANTS AND MAIN OUTCOME MEASURES Newborn screening cards of 443 white case patients with cerebral palsy and 883 white controls were tested for viral nucleic acids from enteroviruses and herpes viruses by using polymerase chain reaction. Herpes group A viruses included herpes simplex viruses 1 and 2 (HSV-1 and HSV-2), Epstein-Barr virus (EBV), cytomegalovirus (CMV), and human herpes virus 8 (HHV-8), and herpes group B viruses included varicella zoster virus (VZV) and human herpes viruses 6 and 7 (HHV-6 and HHV-7). RESULTS The prevalence of viral nucleic acids in the control population was high: 39.8% of controls tested positive, and the prevalence was highest in preterm babies. The detection of herpes group B viral nucleic acids increased the risk of developing cerebral palsy (odds ratio 1.68, 95% confidence interval 1.09 to 2.59). CONCLUSIONS Perinatal exposure to neurotropic viruses is associated with preterm delivery and cerebral palsy.