Death by infection? What happened?

[GailTheSnail]

Does anyone know what it means when a snail is found dead and the body is yellow and there’s bubbling around the breathing hole? Kind of a sulfur smell too? It has happened to otherwise healthy snails out of the blue and I have only seen it a few times but I’m wondering if anyone knows what it means.

[agrif01]

Unfortunately the causes are little known, it could be infection (very often)
the whole thing is then linked to the genetics of the snail and the parameters of housing (temperature, humidity..)