Personally I think it is a big bunch of hoopla about nothing. You are at risk from any number of things even before you get out of bed so why bother worrying yourself to an early grave about it? I personally give more thought (not much more to be honest though, I am pretty carefree about the vast majority of life's dangers, apart from sharks - go figure eh?
) to the tank's macro inhabitants rather than it's micro ones I.E: the fish, etc. Spines, venom glands and teeth make for an entryway into the body which is where 99% of the problems are likely to occur anyhow.
Best advice I can give is just to use your noggin really, common sense is your best aid with everything in life. Wash your hands after having them in the tank (especially before preparing food), don't drink the water as much as you can help it (honestly, how many people go out of their way to cop a gobfull? There is always such thing as a kitchen tap
) and always be aware about the fish you keep and whether they are venomous, spikey, bitey or in any other way, shape or form a hazard to your wellbeing. If they are likely of giving you a nip, puncture, etc then buy a piece of perspex with which to isolate them from you when doing stuff in the tank and always keep one eye on the job and one on the fish
scary
. It looked terribly, felt even worse and nearly made me sick. However, within 5 days I was right as rain, the associated fever went down and everything was better. If you ever have a fever that has no other symptoms, swollen glands and any painful or red sore scabs see a GP and just get them to check: stop the infection before you end up 
