20171005 Rumen Fluke (Branding Update)

ANIMAL HEALTH IRELAND Parasite Control leaflet series Contributing to a profitable and sustainable farming and agri-food sector through improved animal health

Rumen Fluke - the facts

Adult rumen fluke attached to the lining of the rumen of a cow. Magnified c. 4x life size.

PARASITE CONTROL PROGRAMME

Animal Health Ireland, 4-5 The Archways, Carrick-on-Shannon, Co. Leitrim, N41 WN27

AHI gratefully acknowledges the financial and other contributions of our stakeholders.

PARASITE CONTROL PROGRAMME

Animal Health Ireland, 4-5 The Archways, Carrick-on-Shannon, Co. Leitrim, N41 WN27

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Please refer to the disclaimer on the last page regarding information in this leaflet.

Introduction Rumen fluke are parasites of ruminants and occur worldwide. They have a snail intermediate host. The adult parasites live in the rumen (stomach) and the immature larval forms live in the small intestine. Clinical disease is due to intestinal damage caused by massive numbers of larvae in the intestine. The adult worms in the rumen are not usually considered to cause disease. In recent years, the prevalence of rumen fluke in Ireland and the United Kingdom has increased. A few fatal cases have been recorded by the regional veterinary laboratory service and veterinary surgeons in practice see occasional cases of clinical disease. Many cattle have small numbers of adult rumen fluke in their stomachs and have rumen fluke eggs in their faeces. Small numbers of adult parasites cause little or no damage. It is important to distinguish between the mere presence of rumen fluke in animals that are performing well and disease associated with rumen fluke. This leaflet will give you some background information on rumen fluke. Your veterinary surgeon will help you reach a diagnosis and decide if a control programme for rumen fluke is required on your farm. Liver fluke and rumen fluke can be found on the same farm so it is important to remember that liver fluke disease is always harmful and should be given priority, whereas rumen fluke only rarely causes disease. Life Cycle Preliminary scientific investigation suggests that the principal (if not the only) rumen fluke in cattle in Ireland and U.K. is Calicophoron daubneyi which uses the mud snail Galba (Lymnaea) truncatula as its intermediate host. This snail also acts as the intermediate host for the liver fluke Fasciola hepatica .

Figure 1. Life cycle of rumen fluke Calicophoron daubneyi Both cattle and sheep are equally susceptible to infestation

Rumen Fluke - the facts

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What are the signs that rumen fluke may be a problem in your herd? Clinical disease occurs occasionally in Ireland . The following clinical signs have been reported: • dullness • dehydration • rapid weight loss • severe watery scour, which may contain traces of blood • low blood protein concentrations • swelling under the jaw, known as bottle-jaw, or in Irish ‘pocán’. Left untreated, severely affected animals may die due to dehydration. The clinical signs described above are not exclusive to rumen fluke, so diagnosis by clinical signs alone is unreliable. However, certain features of the disease such as severe scour and weight loss, abnormally low levels of albumin (a blood protein) in blood samples combined with a history of grazing wet ground, especially in the late summer or autumn would raise suspicions. Demonstration of rumen fluke in a faecal sample (eggs/larvae) would help confirm the diagnosis. Laboratory testing will readily detect eggs in the faeces of an animal carrying adult rumen fluke. The eggs superficially resemble those of liver fluke, but laboratory analysts can easily differentiate between them. It is much more difficult to confirm disease caused by the immature fluke (larval paramphistomosis) but sometimes laboratory testing may demonstrate rumen fluke larvae in faeces. This test may not be widely available and negative findings do not necessarily rule out the diagnosis. To detect rumen fluke eggs or larvae, the laboratory will require approximately 20 grams of faeces (a dessert spoonful), packed in a watertight, clean, non-breakable container, and marked with the animal’s tag number or other identification. Blood samples are required to test for blood proteins.

If disease caused by immature rumen fluke is suspected, a faecal sample may be checked for eggs and larvae. (Occasionally, small numbers of eggs may be present in larval paramphistomosis). In very severe cases, observed by the Irish Regional Veterinary Laboratories, large numbers of immature rumen fluke have been found in the faeces. The finding at post mortem examination of large numbers of larval rumen fluke attached to the wall of the small intestine in an animal that showed the clinical signs described above is a very reliable way of confirming the diagnosis of severe disease due to immature rumen fluke (larval paramphistomosis). Note that carcases must be very fresh for accurate diagnosis as larvae detach from the intestinal wall shortly after the death of the host animal.

Rumen fluke egg

Contact your own veterinary practitioner to plan rumen fluke Investigation and control programme

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Rumen Fluke - the facts

Why does disease due to rumen fluke occur? Cattle appear to be more susceptible to rumen fluke infection if they are young, sick or poorly nourished. However, if there are very large numbers of infective larvae on pasture such as in heavily grazed WET areas, all cattle are susceptible.

Grazing on damp or waterlogged pastures is also a significant risk factor, especially in a wet summer.

Grazing damp or waterlogged pastures is a significant risk factor, especially in a wet summer.

Traditionally, the rumen fluke was not considered to be a significant parasite of Irish cattle, mainly because it was only seen in very low numbers, and was not associated with clinical disease. In recent years, however, a number of very severe outbreaks, with multiple fatalities, have focused attention on the rumen fluke. The characteristic eggs have been increasingly detected in faecal samples over the same period. This may be partly due to increased awareness of the parasite and separate reporting by laboratories of liver fluke and rumen fluke eggs but recent examination of archived samples indicate that the increase in incidence is real.

Rumen Fluke - the facts

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How can I control Rumen Fluke in my herd? 1. REDUCE EXPOSURE Reduce the possibility of exposure to rumen fluke larvae on pasture. Restricting access to fields, or parts of fields, which are or have been wet or water logged will reduce exposure to contaminated herbage. The fencing-off of drains, ponds and watercourses should also reduce exposure. These measures also have the added benefit of reducing exposure to liver fluke.

Most drugs that kill liver fluke do not kill rumen fluke

2. TREATMENT Flukicidal drugs.

Most of the drugs that control liver uke DO NOT kill rumen uke. Although not specifically licensed in Ireland for the treatment of rumen fluke, it has been reported in the scientific literature that oxyclozanide can kill both mature and immature stages of this parasite. The dosages and treatment frequency described in the literature for oxyclozanide against rumen fluke differ from those recommended for liver fluke control and expert advice on this should be sought. Oxyclozanide is not effective against immature liver uke, but it will kill immature rumen uke. After treatment, cattle may occasionally show transient scouring and lack of appetite and dairy animals may have decreased milk yield.

Current veterinary advice to prevent the development of resistance is to avoid the over-use of any flukicide. Routine treatment for rumen fluke is rarely justified except on farms where severe clinical disease has been confirmed in the past. Even in these cases, treatment should only be administered when clinical disease has been diagnosed as this drug has no persistent effect against rumen fluke. Close monitoring is essential on farm, and for the best advice on treatment and control options, you should consult with your own veterinary practitioner.

The mud snail, Galba truncatula; the intermediate host of liver (F.hepatica) and rumen fluke (C. daubneyi).

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Rumen Fluke - the facts

How should I approach the treatment of rumen fluke on my farm? It is important to remember that the detection of rumen fluke eggs in faecal samples, or the detection of the adults in small numbers in the rumen is not in itself a reason to institute specific control measures, as light infections appear to have no effect on animal health or productivity. The routine implementation of a preventive dosing regime for rumen fluke is rarely justified, except on farms where severe disease and losses have been confirmed in the past. Because of the rarity of severe outbreaks, such a control schemewould be best designed and tailored for the specific farm in question, following consultation with your own veterinary practitioner. Such a scheme would aim to use treatment in a strategic manner to reduce pasture contamination, in association with other measures mentioned previously.

Apart from the economic costs that arise from unnecessary use of any anti-parasitic drug, it is especially important to treat rumen fluke sensibly and sparingly, given that there is only one effective compound (oxyclozanide). The development of oxyclozanide-resistant strains of rumen flukemust be avoided and there is a heightened risk of resistance if a single compound like oxyclozanide is used indiscriminately over several years. It is important that management of rumen fluke is undertaken as part of a comprehensive parasite control programme that will control liver fluke, gut worms and lungworm (hoose) as well as rumen fluke.

Do not treat rumen fluke unless clinical signs are present

TECHNICAL WORKING GROUP Andrew Forbes (Chairperson) - School of VeterinaryMedicine, GlasgowUniversity, Mícheál Casey - DAFM Regional Veterinary Laboratory, Backweston, Charles Chavasse - Zoetis, Bosco Cowley - MSD Animal Health, Martin Danaher - Teagasc Food Research Centre Ashtown, John Gilmore - Veterinary Practitioner, Barbara Good - Teagasc, Athenry, Fintan Graham - Veterinary Practitioner, Ian Hogan - DAFM, Veterinary Laboratory Services, Maura Langan - Norbrook Laboratories, Jennifer McClure - ICBF, Grace Mulcahy - UCD School of Veterinary Medicine, Tom Murphy - Parasitology Specialist, DAFM, Maresa Sheehan, DAFM INTELLECTUAL PROPERTY All images contained in this leaflet are the property of AHI, or have been included with the permission of the owner. Please seek permission from AHI if you wish to use these images and provide the correct attribution of ownership when reproducing them. If reusing any other material in this leaflet, please attribute AHI as the source. Front cover photo courtesy of Pat Sheehan SLA, Cork RVL. Rumen Fluke egg photo courtesy of Jim O’Donovan RO, RVL Athlone. Lifecycle image created by RVL Division. IMPORTANT NOTICE - DISCLAIMER This leaflet is issued and shall be read only on the basis that it will not be relied upon by any person as a basis for any act or omission or otherwise without obtaining professional veterinary and health and safety verification and advice and that no liability or responsibility to any person is accepted or shall be incurred, and no recourse or claim by any person will be made, by or against AHI,any stakeholder, collaborator, officer, agent, subcontractor or employee of AHI, any member of the Technical Working Group, any contributor to, author, publisher, distributor, reviewer, compiler or promoter of or any other person in respect of

Regional Veterinary Laboratory, Kilkenny Donal Toolan - recently retired from DAFM Regional Veterinary Laboratory, Kilkenny, Theo de Waal - UCD School of Veterinary Medicine TECHNICAL WORKING GROUP RAPPORTEUR Rebecca Carroll - Animal Health Ireland PEER REVIEW BY Dr. Eric Morgan - University of Bristol. Prof. Bob Hanna - Agri-Food and Biosciences Institute, Belfast. or in connection with the leaflet or the contents thereof or any matter omitted therefrom. No representation or guarantee is given, whether by AHI or any other such person, that the contents of this information leaflet are comprehensive, up to date, or free from error or omissions, nor that the advice provided is appropriate in every particular circumstance. The contents of this information leaflet are not intended to be a substitute for appropriate direct advice from your veterinary practitioner. Appropriate veterinary and health and safety advice should be taken before taking or refraining from taking action in relation to the animal disease dealt with in this information leaflet. The contents of this leaflet may be updated, corrected, varied or superseded from time to time by later publications or material on the AHI website and reference should be made to that website accordingly. Any references in this booklet or links in the AHI website to external websites or other resources are provided for convenience only and the contents thereof are not to be considered as endorsed thereby.

Animal Health Ireland, Main Street, Carrick-on-Shannon, Co. Leitrim Phone 071 9671928 Email admin@animalhealthireland.ie Web www.animalhealthireland.ie

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