Lamb liver fluke antibody test results - August 2021

Using abattoir blood samples from slaughtered lambs to detect the timing & spread of fluke infection

Since 2015, from June to December, DAFM has taken lamb blood samples in factories from a proportion of flocks at the time of slaughter. These have been tested for liver fluke antibodies to determine the timing and geographical spread of liver fluke challenge to grazing lambs.
The number of flocks selected for sampling from each county is intended to be proportionate to the sheep population of that county over the entire sampling period (June to November 2019). A number of samples are taken from each selected flock, and these are pooled at laboratory level. The presence of liver fluke antibodies reflects the level of challenge the lambs have experienced during the most recent grazing season. The presence of liver fluke antibodies in 2021 born lambs is therefore a sentinel for exposure to liver fluke in the wider sheep population in the region, as by definition these lambs must have been exposed during the 2021 grazing season.

Results up to and including August 2021

Results for the country, for July and for the year up to and including July 2021, are as follows:

Results up to and including August 2021

 Please see maps in Figure 1 below for more detail on the distribution of positive and negative results.  


Figure 1 shows the distribution of positive, negative and inconclusive tests across the country.


Samples from 179 flocks were submitted, of which 20 were positive and 30 were inconclusive. Of the positive samples 2 were heavy infestation, 5 moderate infestation and 13 low grade infestation.  The 20 samples were distributed across counties Mayo (7), Cork (4), Donegal (2), Kildare (2), Kerry (2), Westmeath (1), Tipperary (1) and Wicklow (1).   The 30 inconclusive results came from flocks in counties  Galway (8), Roscommon (7), Sligo (3),Kerry (2), Carlow(2),Mayo (1),Dublin (1), Kildare (1), Kilkenny (1), Donegal (1), Westmeath (1), Wexford(1) and Wicklow (1). 

The greatest burden of fluke infestation was recorded in the west and North West of the country, which is not unexpected as it is associated with rainfall.  The exposures recorded to date were relatively low, but nonetheless this serves to remind us of the risk posed by liver fluke.  There is always a need for caution when assessing the liver fluke status of Irish sheep flocks, and of the need to consider information from a range of sources when deciding whether or not to dose.  

As the sample size for some counties is small, farmers in these particular counties need to be cautious when interpreting the results of the survey as they relate to their areas. Additionally the county associated with a batch of lambs is that where the flock of submission is registered. In a minority of cases, where the lambs had been purchased shortly before slaughter, the county associated with a batch will not reflect accurately where the batch of lambs spent its life.  

Thanks to Seamus Fagan of Athlone Regional Veterinary Laboratory, Padraig Kelleher of VPHIS and Kate O’Keeffe, DAFM blood testing laboratory in Cork for the information provided.

Species: Ovine
11:42 AM on Wed, 22 September