A decreased level of consciousness occurs in 0.5–6% of severe cases, which is attributable either to inflammation of the brain by the virus or indirectly as a result of impairment of vital organs, for example, the liver.
严重病例中0.5－6％会发生意识水平下降，这是由病毒导致的脑组织炎症所致或重要器官例如肝脏的损伤间接引起。