Look out for fluke!
Acute rumen fluke was diagnosed
as the cause of death in a four-year-old ewe last week at Dumfries. The
ewe was the third to die in a group of 60, and the other ewes in the group were
noted to be leaner than expected. This ewe had scoured before death, and
at post mortem intestinal content was watery and malodorous. Very large
number of immature rumen fluke were detected in the duodenum and jejunum, the
surface of which was covered by fibrin.
- It is worth
noting that the clinical signs of acute malodourous scour and deaths
particularly in adult sheep are quite specific, unusual and worth looking out
For these cases to occur there
has to be ingestion of massive numbers of metacercariae, followed by attachment
of the immature rumen fluke to the small intestinal mucosa causing the severe
diarrhoea seen. The pictures below are of the duodenal damage and the
appearance of the immature fluke. Risk factors for
rumen fluke are the same as for liver fluke. These ewes were on a silage
aftermath but areas of wet ground were also present. Ewes on this field
had experienced losses associated with liver fluke in autumn 2015.
- The practice of
putting grazing stock directly on to silage aftermaths after the fields have
been cleared is a risk for acute fasciolosis and rumen fluke infection as stock
will graze more intensively on the wetter areas and field margins where
tractors and machinery can not travel.
Oxyclozanide is the usual
treatment for rumen fluke although the products have no licence claim against
the parasite. It is not effective against the juvenile stages of liver
Acute rumen fluke remains
uncommon in this area (one previous outbreak was diagnosed at Dumfries in
January 2012) but should be added to your list of differential diagnoses in
cases of scour and death in sheep and young cattle. The jury is still out
on the significance of adult rumen fluke infection which is considered to be an
incidental finding, with clinical disease rare.
- Given that liver fluke
remains the more important parasite in terms of disease and production loss,
routine autumn treatments should continue to specifically target immature liver
the way in Agricultural and Rural Research, Education and Consultancy.