Ok, I had to Google that one…”Moggy” not being a typical Canadian term. Apparently, it’s British slang for "cat." Anyway, the "Death by moggy” article in the UK paper The Sun is pretty basic, mentioning the death of a 59-year-old woman who would probably be considered a classic cat hoarder. She was single and slept with 15 cats in her room, and as described by the coroner “hygiene was not what it could have been due to so many animals.”
I actually don’t buy the "number of animals" excuse. Fifteen cats is a lot, but cats are pretty clean and with some effort, it’s not hard to maintain a hygienic environment. It’s a lot of litter to clean, but it can be done. If there were hygiene issues, it probably went beyond a problem of sheer cat numbers.
Regardless, the report is pretty brief but it appears that the woman died of sepsis (overwhelming bloodstream infection) that was somehow linked to the cats. There’s no mention of whether the cats were actually the source, or if it was a matter of "lots of cats…big mess…must be from the cats." However, the woman was apparently often scratched, so it makes sense that the cats could have been the source of infection or a scratch could have allowed a bacterium from the woman’s skin to cause an infection that ultimately killed her.