UK Parasite Watch July Edition: Parasitic Gastroenteritis (PGE)

What is PGE?

Sheep Parasitic Gastroenteritis or PGE is one of the biggest challenges to the welfare and economic value of keeping sheep, being the most commonly diagnosed cause of mortality in young lambs in England and Wales.

As the infective period progresses eggs will be shed onto pastures by infected animals. High pasture burdens may lead to disease and reduction in welfare and profit.


What causes PGE?

The causative agents of PGE are Teladorsagia (Ostertagiacircumcincta and Haemonchus contortus in the abomasum and  Trichostrongylus species and Nematodirus battus in the small intestine. At RRL we culture Teladorsagia (Ostertagiacircumcincta and Haemonchus contortus, if you would like to purchase them.

Haemonchosis

Haemonchosis is a type of parasitic gastroenteritis caused by the parasite Haemonchus contortus. Most diagnoses made by APHA occur from July-September, meaning now is the time to act and test your flock or herd. The main indication of haemonchosis is anaemia, however diagnosing by this alone is difficult and is why you should test for the parasite. Be careful worming without recurrent testing as this parasite can become resistant to anthelmintics quite easily.

Nematodirosis

Nematodirosis is caused by the Nematodirus battus worm and is more commonly observed in April – June, but however can have another peak in the autumn. Signs of nematodirosis consist of sudden diarrhoea, dehydration and eventually death. For predictions for this year and the future, see the SCOPS website. Ensure to monitor the infection of your animals to prevent them contracting nematodirosis.

What can I do to prevent PGE?

There are steps to take now to prevent excessive infection and keeping PGE causing roundworms to a minimum:

The route of action to take is a combination of pasture rotation and management and using diagnostics to monitor infection rates and help to select the anthelmintics used, preventing resistance. We can perform routine worm egg counts from early to late season grazing, allowing you to catch an infection and nip it in the bud. We also provide worm egg count reduction tests which allows you to monitor the infection after worming i.e. the efficacy of the wormer. We can perform these counts on individual samples or a composite sample from your flock.

Similarly, we can also perform pasture larval counts which will advise you which parasites are present and so you can avoid the land or be prepared with the correct treatments.

All of these tests can also be performed for cattle or any other grazing animal. PGE can also affect cattle.

Visit NADIS for more information on these diseases and other seasonal parasites.

References:

https://veterinaryrecord.bmj.com/content/179/9/223.full

https://www.nadis.org.uk/parasite-forecast/

APHA (2016) Disease surveillance in England and Wales, February 2016. Veterinary Record 178, 208–212

https://www.scops.org.uk/internal-parasites/worms/nematodirus-in-lambs/