'Rumen fluke - emergence of a new 'old' parasite problem?'

Philip J. Skuce, Moredun Research Institute,

Edinburgh , UK

AHDA Conference, Birmingham January 29th 2014

Adults in the rumen…

Videoclip kindly provided by Willie Thomson, Harbro Ltd.

Rumen fluke - paramphistomes

• Digenean (2-host) trematode parasites of sheep, goats, cattle, deer etc.

• Prevalent in tropics/sub-tropics

• Have been described in UK livestock as far back as 1950s – abattoir study in Glasgow

• Species thought to be Paramphistomum cervi (P. hiberniae & P. scotiae) – wildlife↔ livestock?

• Rumen fluke eggs started to appear in ROI & UK diagnostic samples late 2000s (Murphy et al, 2008; Foster et al, 2008)

• Thought to have similar life-cycle to liver fluke and often found as co-infections in sheep & cattle

Willmot, J. Helminth. 1950;24:155-170

Rumen fluke life-cycle

???

Current prevalence?

• Diagnosed as presence of rumen fluke eggs in faeces and/or rumen fluke parasites at post mortem

• Currently diagnosed in ~30% of sheep & 40% of cattle in NI (AFBI 2013)

• AHVLA report ‘as many diagnoses of rumen fluke in UK in 2012 as previous 5 years combined’ (R. Daniel, AHVLA, pers comm)

• Sales of flukicides containing oxyclozanide have increased x 600% in Ireland in 2012!?

© AHVLA

• Adult rumen fluke well tolerated on surface of rumen itself – clinical disease invariably associated with heavy infestations of immature rumen fluke in the intestine

• Only 2 recent reports of disease and death caused by rumen fluke; one in sheep, one in cattle - common denominator? – young stock & flooded farms!

(Mason et al; Millar et al, Vet Record 2012)

• Symptoms include anorexia, anaemia, ill-thrift, non-responsive diarrhoea etc…variously described as ’profuse, fetid, projectile, bloody’…

• No scientific data on production effects, only anecdotal reports of animals improving in condition post-treatment

Clinical relevance?...

© AHVLA

© AHVLA

© SAC VIS

© SAC VIS

• Important to keep rumen fluke in perspective – the parasite IS becoming more common, BUT clinical disease is still rare, liver fluke remains the biggest threat to UK livestock!

How important is rumen fluke?...

© AHVLA

Fluke and CAP reform dominate NSA UK Policy and Technical meeting. Tuesday this week (26th February) saw the NSA UK Policy and Technical Committee, which meets four times a year to discuss key policy areas, gather in London. There was an extensive agenda but the two items drawing passionate comment from our English, Scottish, Welsh and Northern Irish representatives were liver fluke and Defra’s attitude to CAP reform. There was real strength of feeling about the damage caused by liver fluke and the lack of understanding about the different products available – and specifically that triclabendazole products are the only ones that kill immature fluke but care needs to be take not to cause resistance to the drug. As always, NSA recommends members visit www.scops.org.uk, but we are also working in a number of other areas to ensure the need for new tools is fully appreciated by the wider industry.

Rumen fluke – Treatment options • Advice from AHI and others – don’t treat unless

there are clinical signs of paramphistomosis!

• Only one drug, Oxyclozanide, has confirmed

activity against rumen fluke (closantel?) –

immatures & adults

• None of the flukicides containing oxyclozanide

have a label claim for rumen fluke

• Oxyclozanide is a liver fluke drug in its own right –

only kills adults

• Widely used to treat liver fluke in dairy cattle (not

many options!) – attractive because of ~short

(0-72h) milk withhold!

• For up-to-date information, consult VMD at

http://www.vmd.defra.gov.uk

• Faecal egg count – eggs could be confused, leading to mis-interpretation of liver fluke treatment outcome?

• Faecal antigen ELISA – MM3 Mab from commercial Bio-X kit – specific for F. hepatica, does NOT cross-react with rumen fluke

Implications for liver fluke diagnosis?

A. Liver fluke B. Rumen fluke Vet Record, Oct 2012

Rumen fluke species identification

• Presumed to be Paramphistomum cervi in UK

• Rumen fluke (adult, juvenile, eggs) from home-bred Scottish cattle and sheep

• PCR and DNA sequencing of ITS-2 region (Rinaldi et al, Vet Para, 2005): database searching & sequence alignment…

Calicophoron daubneyi – the predominant rumen fluke species in mainland Europe e.g. France, Spain, Italy…

• Wanted to broaden our search in UK & Ireland…

Gordon et al, Vet Para, 2013

All Calicophoron daubneyi…have yet to find P. cervi…

Thanks to contacts at AHVLA & Teagasc

Including immatures from the Miller et al clinical/fatal case at Langford!

Sourcing reference specimens…

Laura Rinaldi, Naples – genuine Calicophoron daubneyi from Italian sheep

Marian Varady, Kosice – genuine Paramphistomum cervi from Slovakian red deer

Johannes Charlier, Ghent – clinical case in dairy cattle

Maria Martinez-Valladares, Leon – genuine Calicophoron daubneyi from Spanish sheep

and in different hosts… • Deer - ~50% have liver fluke by FEC &

cELISA, no rumen fluke detected to date

• Alpaca – fatal case nr Ripon, species ID = C. daubneyi

• Reindeer – eggs awaiting PCR

• American Bison – eggs in the post!

Calicophoron daubneyi - what’s in a name?

Q1. How did it get here?

• Animal transport? Theories include European water buffalo coming in to S. England & Limousin cattle from France – but it’s endemic across UK & ROI!?

Calicophoron daubneyi - what’s in a name?

Q2. How long has it been here?

• Extracting DNA from archived clinical material from AHVLA (paraffin wax blocks) – method works e.g. Miller et al case, 2012 - need to source older material!?

Calicophoron daubneyi - what’s in a name?

Q3. Implications for epidemiology/ disease?

• Pathogenicity - C. daubneyi > P. cervi in livestock?

• Wildlife host? – none reported for C. daubneyi

• Snail intermediate host - planorbid vs lymnaeid snails? In Europe, where C. daubneyi is dominant, favoured snail intermediate host is Galba truncatula!

Implications for liver fluke diagnosis: DNA-based testing

• Recent evidence suggests it is possible to detect liver fluke DNA in faecal samples from ~2-weeks post-infection

• ~New DNA-based method, Loop-mediated Isothermal Amplification (LAMP), has potential to offer rapid (<1hr), visual readout without any specialised equipment

• Published LAMP assay for liver fluke – cross-reacts with rumen fluke!

• Have subsequently developed LAMP assays that are specific to liver fluke and rumen fluke, respectively.

PCR

• Rumen fluke on the increase in UK & ROI - predominant species is Calicophoron daubneyi

• Main significance at present is through its implications for liver fluke diagnosis

• Require non-invasive diagnostic methods that can discriminate between liver fluke & rumen fluke

• Require a better understanding of rumen fluke epidemiology in UK & ROI, esp. preferred snail intermediate host +/- wildlife hosts

Conclusions and future work

Acknowledgements

Moredun Staff & Students

- Ruth Zadoks, Danielle Gordon, Naomi Lean, Lydia Roberts, Lisa Imrie, Nicola Sargison & Stuart Dawes, Gillian Mitchell

R(D)SVS – Neil Sargison

Harbro-MacKintosh Donald

- Willie Thomson, David MacKenzie & Erin Strachan

QMS Grant-in-Aid

AHVLA, SAC VIS & Teagasc contacts

- esp. Roger Daniel, Sian Mitchell, Michael Miller, Heather Stevenson, Helen Carty, Rachael Morris, Tim Bebbington, Donal Toolan

EU-contacts

- Laura Rinaldi (Naples); Marian Varady (Kosice); Maria Martinez-Valladares (Leon); Johannes Charlier (Ghent)

Scottish Government