Does anyone have personal experience of sensing that their PD has advanced noticeably after having a bout of fever or infection?
No, I've never had a fever, infection or even a mild cold since being diagnosed with PD.

Also, can anyone point to where this topic has been discussed?
The best review of this topic that I've come across is this one

Why is there motor deterioration in Parkinson’s disease during systemic infections-a hypothetical view
http://www.nature.com/articles/npjparkd201514

Also may want to check this one out:
Umemura A, Oeda T, Tomita S, Hayashi R, Kohsaka M, Park K et al. Delirium and high Fever are associated with subacute motor deterioration in Parkinson disease: a nested case-control study. PLoS One 2014; 9: e94944.