Acute/subacute fluke - treatment and prevention
Last updated month/year 03/10/2023
- When should I treat acute/subacute fluke?
- What can I use to treat acute/subacute fluke?
- How can I prevent acute/subacute fluke on my farm?
As with gut worm resistance, liver fluke resistance, especially to products containing the active ingredient, triclabendazole is relatively common in the UK sheep flock. This is especially important to note when treatment for acute/subacute fluke infection is necessary in late summer/autumn as triclabendazole is the only effective option against early immature fluke.
To avoid unnecessary or incorrect treatments for liver fluke, it is imperative to use the diagnostic tests available to diagnose if fluke is present. If fluke is diagnosed, you should determine the type of fluke likely to be causing disease, in conjunction with your vet or SQP/RAMA, and select the most appropriate drug available.
When should I treat acute/subacute fluke?
Previous history of liver fluke on your farm and the fields where lambs are grazing should be considered along with parasite forecasts such as NADIS (preferably a local forecast to your farm which will be more area-specific) to decide on the current risk of fluke infection. If you suspect fluke or are concerned the risk is high, you can use the diagnostic tools available as discussed in ‘Acute and subacute liver fluke (fascioliasis) in lambs – clinical signs and diagnosis ’.
Acute/subacute liver fluke can be difficult to diagnose because fluke egg detection is not an appropriate method for diagnosis. Fluke eggs are only produced by adult fluke, which take between 10 and 12 weeks to mature from eggs ingested by the sheep to egg-producing adults.
Post-mortem of any dead lambs, blood samples to test for antibodies (picks up evidence of fluke 2-4 weeks after infection) and abattoir reports can all be used to determine if lambs are affected by acute/subacute liver fluke.
What can I use to treat acute/subacute fluke?
There are limited options for treating fluke in lambs, especially acute and subacute fluke, as there is only one active ingredient that kills immature fluke – triclabendazole (e.g. Tribex). Triclabendazole resistance is becoming increasingly common in the UK, which increases the importance of targeting treatment according to test results and monitoring. In a study published in 2019, a lack of efficacy of triclabendazole was detected on 21/26 farms tested, with faecal egg count reductions ranging from 89% to 0%.1 The results showed that reduced efficacy of triclabendazole was present across England and Wales. Most concerningly, the study found a complete lack of therapeutic efficacy on 9/26 farms.1
If faecal egg counts show there is a significant concurrent gut worm infection, lambs will also need treatment for worms. Combination products such as Tribamec Duo (containing triclabendazole and ivermectin) can be used if both active ingredients are effective on your farm. This combination product can be useful for fat lambs infected with liver fluke and gut worms as the meat withdrawal period is relatively short at 27 days. However, if worms are not a significant problem, a narrow spectrum triclabendazole (such as Tribex) should be used, to avoid unnecessary use of wormers.
There is more choice of products for chronic (adult) fluke, click here for more details on treatment and control of fluke.
If triclabendazole resistance is present in the fluke on your farm, you will need to do everything in your power to avoid or prevent disease, as there are no other active ingredients available to treat early immature fluke. The active ingredient closantel does have some effectiveness against late immature (5-10 weeks old) and can be useful to treat acute/subacute fluke in the Autumn, especially on farms where triclabendazole resistance is confirmed.
How can I prevent acute/subacute fluke on my farm?
Isolation treatment of incoming stock Pasture
There are two main threats to the continued control of liver fluke infections in the UK:
1. Climate change is making the weather patterns in the UK more unpredictable and extreme. A recent update on liver fluke, published by the University of Liverpool, has concluded that the prevalence of fluke is likely to increase, and the timing of outbreaks may become less predictable.2
2. Triclabendazole resistance becoming more common, as described previously.
Prevention of liver fluke is very difficult to achieve practically but there are strategies you can adopt to reduce the risk of infection. Liver fluke prevention is a complex challenge and should be discussed with your vet to devise a bespoke prevention plan for your farm. Strategies that you could adopt include:
1. Timing targeted treatments according to testing (e.g. monthly blood tests on lambs to detect when antibodies to liver fluke are found) and risk assessments according to SCOPS/NADIS forecasts.
2. Diagnosis and targeted treatment of ewes in the spring with an adulticide fluke treatment such as albendazole (Albex) or oxyclozanide (Bovex) to reduce the infection present in the ewes, and subsequently reduce the egg output over the summer.
3. Where possible, avoid grazing animals on high-risk pastures in the autumn, especially in high-risk years (pastures which include habitats that the mud snail like to live in - damp, bare mud, little or no vegetation cover and no shade).
4. Quarantine treatments should be included for liver fluke to avoid buying in fluke, especially triclabendazole resistant Fluke. Consult your vet for advice on fluke treatment during quarantine.
References:
1. Kamaludeen J, Graham-Brown J, Stephens N, et al. Lack of efficacy of triclabendazole against Fasciola hepatica is present on sheep farms in three regions of England, and Wales. Vet Rec. 2019;184(16):502. doi:10.1136/vr.105209
2. Williams, D. (2020), Update on liver fluke in sheep. In Practice, 42: 341-347. https://doi.org/10.1136/inp.m2398
Acute/subacute fluke - treatment and prevention
Last updated month/year 03/10/2023
- When should I treat acute/subacute fluke?
- What can I use to treat acute/subacute fluke?
- How can I prevent acute/subacute fluke on my farm?
As with gut worm resistance, liver fluke resistance, especially to products containing the active ingredient, triclabendazole is relatively common in the UK sheep flock. This is especially important to note when treatment for acute/subacute fluke infection is necessary in late summer/autumn as triclabendazole is the only effective option against early immature fluke.
To avoid unnecessary or incorrect treatments for liver fluke, it is imperative to use the diagnostic tests available to diagnose if fluke is present. If fluke is diagnosed, you should determine the type of fluke likely to be causing disease, in conjunction with your vet or SQP/RAMA, and select the most appropriate drug available.
When should I treat acute/subacute fluke?
Previous history of liver fluke on your farm and the fields where lambs are grazing should be considered along with parasite forecasts such as NADIS (preferably a local forecast to your farm which will be more area-specific) to decide on the current risk of fluke infection. If you suspect fluke or are concerned the risk is high, you can use the diagnostic tools available as discussed in ‘Acute and subacute liver fluke (fascioliasis) in lambs – clinical signs and diagnosis ’.
Acute/subacute liver fluke can be difficult to diagnose because fluke egg detection is not an appropriate method for diagnosis. Fluke eggs are only produced by adult fluke, which take between 10 and 12 weeks to mature from eggs ingested by the sheep to egg-producing adults.
Post-mortem of any dead lambs, blood samples to test for antibodies (picks up evidence of fluke 2-4 weeks after infection) and abattoir reports can all be used to determine if lambs are affected by acute/subacute liver fluke.
What can I use to treat acute/subacute fluke?
There are limited options for treating fluke in lambs, especially acute and subacute fluke, as there is only one active ingredient that kills immature fluke – triclabendazole (e.g. Tribex). Triclabendazole resistance is becoming increasingly common in the UK, which increases the importance of targeting treatment according to test results and monitoring. In a study published in 2019, a lack of efficacy of triclabendazole was detected on 21/26 farms tested, with faecal egg count reductions ranging from 89% to 0%.1 The results showed that reduced efficacy of triclabendazole was present across England and Wales. Most concerningly, the study found a complete lack of therapeutic efficacy on 9/26 farms.1
If faecal egg counts show there is a significant concurrent gut worm infection, lambs will also need treatment for worms. Combination products such as Tribamec Duo (containing triclabendazole and ivermectin) can be used if both active ingredients are effective on your farm. This combination product can be useful for fat lambs infected with liver fluke and gut worms as the meat withdrawal period is relatively short at 27 days. However, if worms are not a significant problem, a narrow spectrum triclabendazole (such as Tribex) should be used, to avoid unnecessary use of wormers.
There is more choice of products for chronic (adult) fluke, click here for more details on treatment and control of fluke.
If triclabendazole resistance is present in the fluke on your farm, you will need to do everything in your power to avoid or prevent disease, as there are no other active ingredients available to treat early immature fluke. The active ingredient closantel does have some effectiveness against late immature (5-10 weeks old) and can be useful to treat acute/subacute fluke in the Autumn, especially on farms where triclabendazole resistance is confirmed.
How can I prevent acute/subacute fluke on my farm?
Isolation treatment of incoming stock Pasture
There are two main threats to the continued control of liver fluke infections in the UK:
1. Climate change is making the weather patterns in the UK more unpredictable and extreme. A recent update on liver fluke, published by the University of Liverpool, has concluded that the prevalence of fluke is likely to increase, and the timing of outbreaks may become less predictable.2
2. Triclabendazole resistance becoming more common, as described previously.
Prevention of liver fluke is very difficult to achieve practically but there are strategies you can adopt to reduce the risk of infection. Liver fluke prevention is a complex challenge and should be discussed with your vet to devise a bespoke prevention plan for your farm. Strategies that you could adopt include:
1. Timing targeted treatments according to testing (e.g. monthly blood tests on lambs to detect when antibodies to liver fluke are found) and risk assessments according to SCOPS/NADIS forecasts.
2. Diagnosis and targeted treatment of ewes in the spring with an adulticide fluke treatment such as albendazole (Albex) or oxyclozanide (Bovex) to reduce the infection present in the ewes, and subsequently reduce the egg output over the summer.
3. Where possible, avoid grazing animals on high-risk pastures in the autumn, especially in high-risk years (pastures which include habitats that the mud snail like to live in - damp, bare mud, little or no vegetation cover and no shade).
4. Quarantine treatments should be included for liver fluke to avoid buying in fluke, especially triclabendazole resistant Fluke. Consult your vet for advice on fluke treatment during quarantine.
References:
1. Kamaludeen J, Graham-Brown J, Stephens N, et al. Lack of efficacy of triclabendazole against Fasciola hepatica is present on sheep farms in three regions of England, and Wales. Vet Rec. 2019;184(16):502. doi:10.1136/vr.105209
2. Williams, D. (2020), Update on liver fluke in sheep. In Practice, 42: 341-347. https://doi.org/10.1136/inp.m2398