My first two piggies died one a year and 7months old, the second 2 years and 2 months old.
Judging by the fact that the three remaining piggies are developing problems I am not expecting them to live past two. They're the 'babies' of the mother who died at a year and 7 months.
My point being, unless you had tests, you won't know what killed the piggy. If it's parents didn't live long, the off spring [*]MIGHT[/*] not live long either, but you woun't know that unless you knew where your piggie came from.
If you disinfect the cage ( vinegar solution or pet wash) it should be enough to kill any germs. Just keep the bowls clean etc (like I am sure you do) and I think the piggy will be fine.
I have been told that washing piggy hutches down with vinegar solution cleans off any smells of 'ownership'. Then rearranging the 'furniture' as though it's new convinces the resident piggy that it's new territory. Personally, I don't think piggies are that daft.
Good luck and let us know how you get on xx