Complex sentence: An early symptoms phase of 1--4 days commonly precedes the onset of encephalitis, manifesting as fever, chills, nausea, vomiting, headache, lethargy and abdominal pain.
Split into simpler sentences: An early symptoms phase of 1--4 days commonly precedes the onset of encephalitis. This phase manifests as fever, chills, nausea, vomiting, headache, and abdominal pain.