Analysis of adaptive mutations selected during the consecutive passages of hepatitis E virus produced from an infectious cDNA clone.

•A cloned genotype 3 HEV (pJE03-1760F/wt) was passaged 10 times in A549 cells.•The Passage 10 virus had two non-synonymous and four synonymous mutations.•Full-length cDNA clones with a single, two, or all six mutations were constructed.•HEV with all six mutations produced 2 logs more virions than did starting virus.•Both non-synonymous and synonymous HEV mutations enhanced virus production.