1.   Although the basal lamina remained visible at many places, the gastric pits of vehicle pretreated rats were uniformly filled with gastric glands.

2.   A small number of gastric glands exhibited characteristic lympho-epithelial lesions.

3.   Histological examination showed small and medium sized lymphoid cells invading gastric glands to form characteristic lymphoepithelial lesions.

4.   The larval stages occur in the gastric glands and can only be seen microscopically following processing of the gastric mucosa.

5.   These changes are maximal when the parasites are emerging from the gastric glands.

6.   The life cycle is similar to Ostertagia and there is penetration of the gastric glands with resultant nodule formation.

7.   After ingestion, and exsheathment in the rumen, the larvae moult twice in close apposition to the gastric glands.