I had not heard of this before today. My neighbour put some greens in for our rabbit and guinea and noticed a wet looking patch on the rabbits back end and a few maggots.
Took her to the vets earlier and she has fly strike. Maggots have been eating into the flesh at the back of her. [eww emoticon!] vet said the fly lays eggs in any poo stuck to the back end of the rabbit which then hatch and eat the rabbits flesh. [double eww!]
Just a warning to any rabbit owners who hadn't heard of this. Check your rabbit daily in the hot weather for any sign of maggots, the eggs hatch within hours of being laid. Luckily ours was caught early and should be ok now it is being treated and the vet has picked off the maggots. (I will have to do this too if i find any! As well as rubbing cream onto the bald area)