Viral amino acidic variations in NS1 and VP1/2 viral proteins from patients admitted or not to the ICU. Shannon entropy calculated for (A) NS1 and (B) VP1/2 viral proteins (lower panels) and between ICU and non-ICU sequences (upper panels). The upper entropy graph shows differences between ICU and non-ICU subsets (purple: not significant). The lower entropy graph shows single viral amino acid variations within the ICU-related viral sequences (purple) and non-ICU–related viral sequences (green). Low entropy differences between protein sequences from ICU and non-ICU subsets suggest conserved proteins and no viral evolution.