Is Georges Pierre Seurat alive

He actually died of a throat infection that was diagnosed as diphtheria.
It is not sure but it is a respiratory disease. (::)
The cause of Seurat's death is uncertain, and has been attributed to a form of meningitis, pneumonia, infectious angina, and/or (most probably)diphtheria.

As far as I can find out diphtheria does not come in different types.