Haemonchus contortus - is the picture changing in your area?

Over the past ten years, SRUCVS have made a total of 46 diagnoses of haemonchosis on Scottish holdings with all DSCs seeing at least one case. Although the number of cases remain small, 46% of these diagnoses have been made in the past three years and there is a general upward trend on a yearly basis (Figure 1).    


   Figure 1 – Diagnoses by year                                    Figure 2 – Diagnoses by month


As expected, cases are most common during the summer and autumn months (Figure 2), after higher summer temperatures have facilitated the lifecycle. Where information was available, weakness and anaemia were the predominant clinical signs with animals also presenting with ill thrift and sudden death. Diarrhoea was not a feature. As adults do not gain solid immunity to Haemonchus, all ages of animals were affected. 31% of the diagnoses were made in camelids and goats. As a highly fecund nematode, undifferentiated strongyle egg counts from confirmed cases ranged from 1250  to 145,350 epg. Worms can be visible in the abomasum, but the  diagnosis can also be confirmed from faecal samples by carrying out the peanut agglutinin test to identify if Haemonchus eggs are present. APHA is offering this test at a discounted cost of £20 for samples submitted to SRUCVS throughout the risk period (usual price £55.70). Please get in touch if you suspect Haemonchus in your area.           

Update: Please note that the free border disease testing scheme (through which we invited the submission of ears from suspect persistently infected lambs in return for free screening of the blood or spleen) has ended. Thank you for participation in this project which has allowed us to gather some ear samples for possible validation of tissue testing in sheep. If you have a strong suspicion of a border disease outbreak in a flock please still get in touch with us, as we may be able to offer some help with testing going forward.

Posted by SRUC Veterinary Services on 04/08/2023

Tags: Parasitology
Categories: Cattle | Sheep | Goats | Camelids