Fig. 1.

Effect of different nutritive media on H. contortus larval development. Basic medium containing only yeast extract and salts fails to promote larval development and the larvae stagnate in L1 stage (a). When sheep faecal extract from egg isolation (flow-through during sieving) is used as media supplement, none of the larvae hatch. The eggs embryonate, but the larvae die before hatching (b). Using living bacteria solution as a food source eventually leads to bacterial overgrowth during the cultivation period of 7 days resulting in death of the larvae and irreproducible L3 counts (c). Addition of heat-treated and lyophilized bacteria solution supports development of larvae to L3 stage without inducing bacterial or fungal contamination (d)