In vitro development of histotropic larvae of Oesophagostomum dentatum under various conditions of cultivation.

We performed a total of 14 trials to evaluate the culture conditions suited best for the in vitro production of fourth-stage larvae (L4) of Oesophagostomum dentatum. Chicken embryo extract was shown to be redundant, whereas pig blood serum, trypticase, liver extract, and yeast extract proved to be important medium ingredients. Development to L4 could be moderately accelerated by increases of temperature (40 degrees C) and of CO2 concentration (20% in air), but the total yield of L4 could not be improved. Thus, conditions of 38.5 degrees C and 10% CO2 are recommended for routine application.