not an expert but i have a few years experience, myxi affects rabbit populations (when there is lots around) then they crash (die off) and it is a natural thing to happen when a spieces has grown to numbers that can not be sustained in that environment. The rabbit looses its natural immune to myxi, some will survive and so the rabbit population will return to the high numbers again. So when they do your best option for keeping clear of myxi is to catch as many as you can without exterminating the population from your permission.