Tests for tuberculin, hepatitis markers, toxoplasma, cytomegalovirus, herpes simplex virus (HSV), varicella zoster virus (VZV), human immunodeficiency virus (HIV), syphilis, aquaporin-4 antibodies (NMO), and myelin oligodendrocyte glycoprotein antibodies (MOG) were all negative. Here, MOG is linked to hepatitis A virus infection.