HSV is most common, causing 50-75% of viral cases (where dx known)
Other common viral causes include: VZV, arboviruses (transmitted by mosquitoes and ticks: West Nile, Dengue, Eastern equine, other), enteroviruses (e.g. coxsackie, echovirus)
Prevalence of viruses can vary w/season, region of the world, exposure history (e.g. to animals, sick persons, environment), health status, immune competency