Dr Emily Boreham MRCVS
The NADIS Fluke Forecast is out: where are you in the 'postcode lottery'?
Fasciola hepatica - aka Liver Fluke is the smallholder's 'postcode lottery'. Thanks to its total dependence on its mud-snail host, Fluke will only occur in very specific locations. This host is accurately named - it loves mud! So the wetter and boggier the ground - the more mud snails & more flukes. NADIS & the met office work together each year to predict the population size of the mud snails and give a risk level to fluke. This year their forecast is slightly worse than 2018, but the overall risk is low in the East, moderate for Western areas, & the only high risk zone is SW Scotland.
Liverpool vet school has mapped positive samples more accurately. The green dots are samples of little or no concern, orange is medium and red is a high infestation. Of note are the dots appearing in East Anglia - this is new.
You'll also notice how close a green dot can be to a red dot - check out the Western tip of Wales inside the box, its a jumble of colours. This comes down to the snail habitat. If your small holding is on the top of a hill, on sandy soil, with no streams, no boggy patches - then you're going to be fine, compared to your poor neighbour down in the valley with their livestock standing knee deep in mud. (of course they get lush green grass every spring whilst you are still serving hay - you win some, you loose some...)
Can you improve your chances?
Come and live in Kent, like me! Don't fancy that?, well there's still plenty you can do:
Know your risk - study the NADIS maps, talk to any neighbouring farms
Minimize mud - improve drainage, fence off ditches or ponds, avoid boggy pastures in summer
Avoid mixing other animals with sheep, this seems to increase the risk
Know what you're looking for & when:
August to October - Acute Fasciolosis:
Profound and sudden weight loss & depression
October to December - Sub-Acute Fasciolosis:
Inability to stand
December to April - Chronic Fasciolosis:
General dullness & lethargy
Pale eyelid membranes & gums due to anaemia
Shortness of breath
Fluid accumulation - legs, belly or under the jaw
So we know our risk, we know what to look for, we've done everything possible to reduce the mud - but we're still worried - can we use a flukicide preventatively?
This is a really difficult answer. You can buy a flukicide from an online pharmacist and treat all your animals during the risk period August to April. But - please, please don't. The days of chucking antibiotics around are over - but we need to use our anti-parasite drugs just as carefully. In a recent study, 26 sheep farms with flukes were followed. 86% showed poor response to our main-line fluke treatment (Triclabendazole), 9 of them showed absolutely zero response to the treatment. If we are not careful, we will soon create a 'Super-bug' fluke.
So when should we use drugs?
If you fulfil any of these criteria:
Your animals are showing some of the symptoms and you've got a positive diagnosis from your vet (blood test or postmortem)
More than one faeces test has come back positive with fluke eggs (check again after 14 days if your stock look healthy but have a low level positive sample)
You have had three consecutive years with positive cases - your farm is officially endemic, unless you make massive changes to your drainage the mud snails are never going away.
The most appropriate drug protocol for your smallholding will need discussing with your vet (or your worm-egg-count provider if they offer an advice service). There's no one-size-fits-all solution, it will vary on species, ages, if you're milking, level of infestation, prior drug use, ease of treatment.. etc etc. Lots to factor in before you plan your treatment.
Good luck through fluke season, I'm always happy to help if you need any advice, Emily