Parasitic Worms

Parasitic gastroenteritis (PGE), caused by infection of the gut with parasitic nematodes, is one of the most important diseases for both Scottish sheep and beef cattle farmers from both a financial and a welfare perspective. The parasitic nematode Teladorsagia circumcincta is endemic in temperate regions of the world and is currently the major cause of parasitic PGE in sheep in the UK. Ostertagia ostertagi  is the major pathogenic species affecting cattle.

Gut roundworm infections (gastrointestinal nematodes) are a major impediment to cattle and sheep livestock production efficiency. Current control is achieved by routine dosing of susceptible stock with drugs (anthelmintics) but this is threatened by the development and spread of drug resistant parasites. The development of resistance by ovine gastrointestinal nematodes to the drugs (anthelmintics) that are used to control them is a major threat to the sustainability of Scottish sheep farming.

Flatworms are also proving problematic to farmers.  Surveillance data shows an increase in the incidence of liver fluke disease in sheep and cattle in Scotland in the last decade.  The disease appears to be spreading into previously fluke-free areas, possibly as a result of recent climate change (milder winters and wetter summers) favouring the parasite and its mud snail intermediate host.  Fluke impacts on milk production, growth rate of beef and lambs, fertility in ewes and, ultimately, the economic viability of production units.

Our work is focused on the need to sustain the present control methods using improved on-farm management strategies and to devise and implement alternatives with vaccination a prime objective. These objectives are supported by the use of the latest technological advances (genomics, transcriptomics, proteomics) to provide definition of the host/parasite relationship at the molecular level.