As the virus passes along to the brain and then to the spinal cord, initial symptoms are fever, fatigue, headache, vomiting, stiffness in the neck, and pain in the limbs.
Nonācis galvas un muguras smadzenēs, sākumā vīruss izraisa tādus simptomus kā drudzi, nogurumu, galvassāpes, vemšanu, stīvumu kaklā un sāpes locekļos.