Which virus is most commonly associated with viral encephalitis?

Herpes Simplex Virus 1 (HSV-1) is most commonly associated with viral encephalitis due to its ability to infect the central nervous system. HSV-1 typically causes cold sores and is widely prevalent; however, when it reaches the brain, it can lead to a severe form of encephalitis known as herpes simplex encephalitis (HSE). This condition is characterized by inflammation of the brain and is considered a medical emergency.

The pathogenesis involves the virus traveling along the sensory nerves to the brain, where it frequently affects the temporal lobes, which can result in significant neurological deficits. Diagnosis is made through clinical presentation, imaging (often MRI), and testing of cerebrospinal fluid (CSF) for the presence of the virus. Early identification and treatment with antiviral medications, such as acyclovir, are crucial to improve outcomes in affected patients.

While other viruses like Enterovirus, Varicella Zoster Virus, and Cytomegalovirus can also cause neurological manifestations, they are less commonly associated with the acute, severe presentation of encephalitis compared to HSV-1.