Barber's Pole Worm: cases on the rise?
Outbreaks of Barber's Pole Worm (Haemonchus contortus) have traditionally been rare in Ireland, with only a handful of cases confirmed each year. Other species of stomach worms (nematodes) have tended to dominate in this part of the world.
However, a spike in the incidence of Haemonchus contortus has been observed in parts of the country this year. Figures published by the Department of Agriculture, Food and the Marine (DAFM) indicate that ruminant deaths attributed to Barber's Pole Worm in the first 10 months of the year are up 164% on figures for the same period in 2022. DAFM's Regional Veterinary Laboratories (RVL) find that Barber's Pole Worm is growing more prevalent in Ireland. Even more alarmingly, it appears that the geographic spread of the parasite is also on the increase.
The Role of Climate
It is difficult to identify why this species is on the rise in Ireland, although increased rainfall and milder autumns due to climate change are surely major factors. All parasitic worms thrive in the warm, wet conditions that Ireland's climate is trending rapidly towards. Projections for the impact of climate change in Ireland indicate that grassland parasites will become an increasing problem for farmers in the years ahead.
Is Barber's Pole Worm Really a Significant Problem?
Any increase in worm risk will be of grave concern to farmers. However, there is reason to believe that Barber's Pole Worm represents a particularly serious problem. It is important to remember that ruminants in Ireland have had limited previous exposure to the parasite, so an infection - if contracted - could prove particularly acute for Irish livestock. In addition, adult sheep cannot develop immunity to the Pole Worm (unlike with other stomach worms).
Symptoms Akin to Fluke?
Then there is the sheer aggression of Haemonchus contortus relative to some other stomach worms. Barber's Pole Worm is a blood-sucking parasite and therefore presents with symptoms not unlike those of liver fluke (bottle jaw, anaemia). Disease related to Haemonchus contortus develops rapidly, with egg counts in infected animals numbering in the thousands rather than the hundreds. Lambs that contract the parasite can die within a month, if not treated. This means that conducting regular faecal egg counts for the worm will be essential for farmers who believe their flock to be at risk of contracting the disease.
How to Treat Barber's Pole Worm?
Management of Barber's Pole Worm in ruminants (and particularly sheep) should focus on treatment with an appropriate anthelmintic drench, followed by a health regimen that will help the animal to recover to full health. According to research conducted by Teagasc on a county Wexford farm dealing with Barber's Pole Worm, treatment with closantel-based anthelmintics (such as Flukiver) is effective in killing worms in infected sheep.
Recovery
Once animals are treated, their faecal egg count should be monitored closely for two weeks for evidence of success. In the study in question, animals kept on good grass supplemented with some concentrate showed rapid progress after treatment.
