No, apparently, she doubled as a prostitute. But of course that was a term used, and still is, by people who view a woman with 'looser morals' than themselves. Hence the 'tart with the cart'.
There is many an opinion, and many's the pint has been drunk debating this very question, but popular thinking has it that the 'fever' referred to as as the cause of her sad and untimely demise, incurable as it was, was non other than the dreaded 'pox' (syphilis).
As mortality rates of the time went, in working class Dublin, it was odds on that it was the 'pox'.

But then that's wat pints are for!!

Oh! barman........?

Breandán