For some unknown reason, an article I wrote about liver fluke in rabbits has become one of the most popular posts I’ve ever published on this blog. You’re very welcome to click through and have a look at it, but there is not a great deal of detail aside from a moderately useful photograph.
I didn’t give the subject much more thought until a day’s course on liver fluke laid on by the SRUC which I attended in October. I knew how much of an impact fluke had had on sheep in the wet summer of 2012, and I was particularly concerned by the thought that my galloways might become infected by these nasty little parasites.
Flukes have a complex lifecycle which is dependent on mud snails, which in turn are dependent upon soggy ground. Young flukes mature inside the bodies of mud snails, and they emerge to form cysts on the grass as they get older. Sheep or cows (or rabbits) eat the cysts along with the grass, at which point the flukes migrate into the animal’s liver, where they burrow through the tissue feeding on blood. Sheep are particularly vulnerable to fluke because their livers just collapse as they are hollowed out, and a sheep can die very quickly with even a moderate number of fluke in its liver. Cows are more robust, and they develop a kind of cartilage around the fluke burrows so while there is a drop in health and condition, death is rare – under usual circumstances, all an infestation means is that the liver could be condemned in the abattoir.
In due course, the fluke lays eggs which are released back into the mud in droppings and the cycle begins again. Farmers have to treat their livestock periodically for fluke, and after 2012 when so many sheep died because fluke ran amok in the wet weather, many now fence off wet areas or invest money in draining them (for better or worse). Wild animals are sometimes blamed for moving fluke around, but the problem seems so ubiquitous that a rabbit or two here or there is hardly going to make a difference. I’m told that roe also carry fluke, but I’ve never found a roe with a liver that was anything other than tip top.
Planting trees today, the dog brought me a rabbit. She had been gleefully thrashing the brambles and digging for some time, and the victory clearly meant a great deal to her. I killed the bunny and brought it home for the ferrets, who are always keen for a piece of the good stuff. All seemed well until I cut open the body and felt that there was something very wrong inside. The liver was stiff and hard, and it was a kind of grey/pink colour rather than the usual dark purple. It was surrounded with jelly-filled cists of young fluke, and as soon as I cut open the tissue, adult fluke came pouring out like blobs of goo. They are surprisingly big things in person, and I pulled out fifteen mature individuals before I finally had enough and threw the whole liver into the burn. I’ve never seen such a badly infected liver, and I even considered throwing the whole rabbit away altogether until I remembered that ferret intestines are the digestive equivalent of the sun’s surface.
Given how awful I feel after a pint or two of cider, I shudder to think how this rabbit must have been feeling over the past few weeks, and perhaps the advanced stage of her condition contributed to her embarrassing death at the hands of my dog. There’s no way Scoop is quick or clever enough to catch a fit rabbit. All told, she was in pretty good condition, and her revolting liver hadn’t stopped her bringing on a batch of six unborn young. This is certainly something to keep an eye on, as I’m increasingly concerned by the general poor performance of rabbits in Galloway. I doubt that fluke is the sole reason why they seem to breed well all summer and the vanish in the autumn, but they certainly aren’t helping.