There are a number of nematode infections that rarely involve the central nervous system. Ascaris lumbricoides and the pig nematode A. suum have been associated with encephalitis. Adult Dracunculus medinensis may invade the spinal cord resulting in epidural abscess and paralysis. Lagochiloascaris spp. are free-living nematodes reported mainly in Brazil. Lagochiloascaris minor infection may cause diseases of the head and neck and the central nervous system. Halicephalobus (Micronema) parasitizes horses and may also involve the human central nervous system.