Under some conditions, nematodes at this stage may lie dormant for several months. Typically, development continues to the adult stage which live in the gut. Eggs deposited on pasture by sheep may develop to L3 and become available for infection. These may be eaten by the same sheep or, more likely, other sheep which graze the pasture. Larvae can persist and infect sheep which have been introduced to the pasture after the original infected sheep have been moved away.
Farmers can bring parasites onto their farms in new stock.