True story - was in South Dakota Custer State Park a few years ago.
Car with family and small children stopped on the side of the park road at the prairie dog town.
They had the kids out wanting to do like a 'petting zoo' and we yelled out the window
"they carry the plague".
Didn't deter these people with their toddlers.
This is the wrong question to ask to start.
The email domain 'ameritech.com' was likely still active. Those are the records to look for - not suggest that the company was defunct.
Case in point.
AT&T bought BellSouth - that domain and email addresses are "STILL ACTIVE".
Do people not know these email domains can live on and be redirected for quite a long time?