In the original comic version of "The Purple Smurfs" (titled "Les Schtroumpfs noirs" or "The Black Smurfs" in English) the bitten Smurfs were black-skinned. The color change in the cartoon version was done to eliminate any racist connotation.
At this point in the Smurf cartoon series' universe history ("The Purple Smurfs"), when Papa Smurf, being bitten by purple Hefty, says that the Smurfs will be no more, Baby, Grandpa, Wild, and Nanny had not yet shown up or been revealed.
The short temper outbursts that Papa Smurf shows in "The Purple Smurfs" was an accurate depiction of his temper in the early Smurf comics like "The Purple Smurfs."
"The Purple Smurfs" is based on a 1959 comic story titled "Les Schtroumpfs noirs" (The Black Smurfs) that appeared as a detachable supplement in Spirou. It is the first stand-alone Smurf story.
In the original comic story of "The Purple Smurfs," it was an un-named Smurf (who will become Grouchy Smurf in "L'oeuf et les Schtroumpfs" or "The Egg and the Smurfs" in English) that was bitten by the fly (called the "Bzz Fly" in the comic; "Purple Fly" in the cartoon), not Lazy. Also, the diseased Smurf who painted himself blue and bit Papa Smurf was also an un-named Smurf, not Hefty.