A neonate is born in very poor condition, with a severe, generalized encephalitis. Which of the following viruses is the most likely pathogen in this setting?

Viral causes of neonatal encephalitis include three members of the herpes family of viruses: herpes simplex I, herpes simplex II, and cytomegalovirus. All three types can have devastating effects on the neonate, with extensive CNS damage leading to mental retardation, seizures, and focal neurologic problems. Acyclovir may be of some help in modifying these infections, but both treatment and prognosis remain very problematic. Eastern equine encephalitis virus and St. Louis encephalitis virus are causes of epidemic encephalitis but are not the most likely cause of neonatal encephalitis. Herpes zoster-varicella virus, unlike herpes simplex, is not usually a cause of neonatal encephalitis. Poliomyelitis virus is a gastrointestinally transmitted virus that is not usually encountered in neonates. Ref: Levinson W. (2012). Pa IX. Brief Summaries of Medically Impoant Organisms. In W. Levinson (Ed), Review of Medical Microbiology & Immunology, 12e.