Although typically associated with tropical and subtropical climates, rumen fluke was becoming a more important and prevalent parasite in the UK.
This was the message from Dr Philip Skuce, Moredun Foundation, who was speaking about the issue at a recent Moredun health and welfare day at Harper Adams, Shropshire.
He said: “Rumen fluke eggs started to appear in diagnostic faecal samples in the 2000s and they are very like liver fluke eggs, only clearer in appearance. This means their appearance is quite subjective and we did not distinguish between them until very recently.”
It has since been found rumen fluke are mostly a species originating from mainland Europe, possibly brought into the UK in cattle from central France.
It has also been found that they also have two hosts, just like liver fluke, which include cattle, sheep, deer, llama and alpacas but were also found in mud snails in Wales and Scotland, which explains why rumen fluke almost always appears in animals infected with liver fluke too.
Dr Skuce said: “Clinical signs are vague and can include anorexia and non-responsive diarrhoea, but can also be fatal. It is easy to dismiss this as a non-issue, but it is becoming very common.”
Infection with immature rumen fluke causes intestinal damage, usually resulting in diarrhoea, anorexia and ill-thrift, dehydration and can sometimes cause high mortality rates in young stock.
Animals that are young, sick or under-nourished are the most susceptible to rumen fluke infection.
“There are some questions over how important infection with rumen fluke is, some people think it is a big deal, some are not convinced, and there is very little data on clinical or production effects,” he said.
However, trials have shown a dramatic improvement in animals’ production after successful treatment for rumen fluke. But it is difficult to isolate the effects of rumen fluke, as most of the animals also had liver fluke too, and the treatment was also effective on liver fluke.
It is relatively easy to detect the presence of adult rumen fluke in faecal samples as they lay eggs.
However, the diagnosis of immature fluke is more difficult. Sometimes fluke larvae can be detected in samples. Therefore, negative results do not always mean there is no infection.
As with liver fluke, grazing waterlogged pastures is a major risk factor for the disease, especially in wet summers.
Dr Skuce said there were a number of practical management actions that can realistically be taken to minimise the risk of animals contracting rumen fluke, and can also be used for avoidance of liver fluke too.
He said: “In spring protect pastures; try not to let animal shed fluke eggs on pastures just as the mud snails are waking up from hibernation.
“Summer is about reducing the snail population and reducing their habitat.
“This can be done by topping rushes, draining wet fields and rolling poached areas.
“In autumn avoid the cyst challenge by fencing off areas which are deemed to be ‘flukey’, even if just temporarily.
“Winter is about treating with the right product to do the right job.”
TREATING RUMEN FLUKE
MOST of the drugs that kill liver fluke do not kill rumen fluke, however oxyclozanide has been found to be effective against both mature and immature rumen fluke.
The dose rate of the treatment differ for rumen fluke and liver fluke, so it is best to speak to a vet about the problem.
Dr Skuce said: “There is no protective immunity, so animals are always at risk of picking up fluke again. And there is no preventative treatment.
“Flukicides do not kill all stages, so it has to be the right product at the right time in the right animals at the right dose given the right way.”
“Fluke drugs are not persistent, which can be an issue in combined fluke and worm products, as some of the drugs they are mixed with are persistent for the treatment of worms.”
Advice from Animal Health Ireland suggests not treating for rumen fluke unless clinical signs are present, as a way of avoiding overuse of flukicides, leading to resistance, especially as there is only one treatment effective for rumen fluke.
Dr Skuce’s tips
Do not assume: Do not assume fluke has gone away because of the nice summer last year
Testing: Understand the status of fluke on your farm, which means testing and not guessing
Management: Understand which product works on your farm and consider other management options available to you
Work with your vet: Use the right product for the right job and always work with your vet