Lungworm and gutworm alert Sep 2020


Disease caused by roundworms have traditionally peaked after mid-July in Ireland, due to a gradual buildup of contamination of the pasture over the grazing season, and environmental conditions becoming very suitable for larvae to develop in late summer. Findings from the post mortem examination of cases recently submitted to the Regional Veterinary Laboratories (RVLs) suggest that the level of pasture contamination with parasites is indeed high this year . A substantial number of cases of both lungworm (hoose) and gutworm have been seen.

Added 22.09.2020

Figure 1: Image of an Ostertagia ostertagi worm in microscopic view. (DAFM RVLs)

Reports from the Regional Veterinary Laboratories (RVLs)

Kilkenny RVL has observed a number of cases of parasitic gastroenteritis in carcases presented to the Laboratory . A high proportion of cases presented are calves and lambs in their first grazing season, and counts of worm eggs in gut contents have been high in several cases. Kilkenny RVL has also seen a substantial number of lungworm cases in recent weeks.

Added 22.09.2020

Figure 2: Lungworm (Dictyocaulus viviparus) in the airway of a six month old calf from a Kilkenny herd; post mortem examination carried out on the 31st August 2020

Meanwhile, Athlone RVL has found several cases of parasitic gastroenteritis in lambs in recent weeks.  

Other laboratories have also seen cases of disease caused by roundworms, as can be seen from the map in Figure 3 below. This map is based on diagnoses of parasitic disease in carcases- it does not include diagnoses reached from tests on submitted samples. Also, not all cases for August have been included, as testing is continuing on some of the submissions from the last few weeks.

Added 22.09.2020

Figure 3: Locations of some cases of lungworm and parasitic gastroenteritis (PGE) in cattle and sheep during July and August



Reports from the RVLs suggest that substantial worm burdens are present on pasture in certain areas. The scale of the problem in animals and herds is not always readily apparent from the appearance of the animals involved. Farmers are encouraged to consider information from a range of sources, including engaging their vet to advise on faecal egg counts, to inform their decision making on treatment and control of roundworm diseases. Lungworm must be considered as a possible diagnosis in grazing first season calves. Farmers are also encouraged to seek a referral from their vet to their local RVL to investigate the cause of deaths in their livestock.

Species: Multi-Species
7:55 PM on Tue, 22 September