Authors

K Fairlie-Clarke²; N Brady²; L Matthews²; M Stear¹;  ¹ La Trobe University, Australia;  ² University of Glasgow

Discussion

In the UK Teladorsagia circumcincta is the predominant nematode of sheep. This parasitic infection causes disease and untreated can result in death. Even a mild infection compromises production reducing weight gain by 25%. In the UK sheep industry alone nematode infection is estimated to cost approximately £84 million a year. With the rise in anthelmintic-resistance it is important to identify animals with natural resistance to parasitic disease.

One of the major mechanisms of resistance to T. circumcincta is the mucosal IgA antibody response. Importantly the IgA response is not associated with impaired host growth. Thus, there is great potential to include the IgA response in selective breeding programs. However measuring IgA responses at the site of infection (abomasum) is not feasible in large flocks. Saliva is a readily accessible source of IgA and can be sampled by simply inserting a swab into the cheek pouch of the animal. We have developed an assay to measure salivary IgA activity against T. circumcincta third stage infective larvae (L3) in sheep. This simple test provides breeders with a means of identifying animals that are suitable for inclusion in selective breeding programs for nematode control.