Bile agar migration test: a novel method for testing the viability of Dictyocaulus viviparus larvae in lungworm...

A bile agar migration (BAM) test was used to determine the viability of Dictyocaulus viviparus larvae in lungworm vaccines. Percentage migration values for 10 batches of vaccine varied from 8.8 to 33.2 per cent compared with 99 per cent of unirradiated larvae tested under similar conditions. On the other hand a conventional viability count (CVC), based on subjective assessment of larval shape, gave figures of 95.1 to 98.7 per cent for the 10 vaccine batches. The BAM test may therefore have potential for providing a more discriminatory assessment of vaccine quality than CVC.