[roadcat]

How in the heck is it not an African disease?

Sounds African to me. They have traditions of washing the bodies of their dead family members. Indeed, some corpses were stolen from hospitals by the families, so they could do the body wash. I don't know about all the people in my town, but I suspect my townsfolk do not wash the bodies of their dead. That sounds African/Muslim.

[Theoria]

Traditions vary. When I was younger there still was a custom of sitting up with the dead at your home. And as for a body, pretty much every funeral home washes the body prior to funeral, and dresses it up. African tribal areas obviously don't have those resources, but they still practice a similar function.