Thunderclap headache caused by Erve virus?

Systematic studies of a possible human neuropathogenicity of the Erve virus have not yet been carried out. In a randomized, blind study 166 patients with viral encephalitis, 46 patients with cerebral hemorrhage, 72 patients with "thunderclap" headache, and 205 healthy blood donors were examined by indirect immunofluorescence for Erve virus antibodies. None of the patients with encephalitis, two patients with cerebral hemorrhage (4.3%), 10 patients with thunderclap headache (13.9%; p < 0.0001), and two blood donors (1.0%) exhibited antibodies against the Erve virus. These results suggest a human pathogenicity of the Erve virus for the first time.