Studies on the In vitro Growth of Parasitic Nematodes. I. Complete or Partial Parasitic Development of Some Gastrointestinal Nematodes of Sheep and Cattle

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Abstract
Utilizing a medium designated "Ae," composed of chick embryo extract, serum, sodium caseinate, vitamins, a hog-liver extract, a balanced salt solution, an indicator, and antibiotics, it was possible in a roller drum to cultivate the parasitic stages of Cooperia punctata, C. onchophora, Ostertagia oster-tagi, O. circumcincta, and O. trifurcata from mixed inocula. Cooperia punctata, O. ostertagi, and O. circumcincta (and/or O. trifurcata) were cultivated to the egg-laying stage. In the case of C. punctata large numbers of eggs were demonstrated but all were infertile as were the smaller numbers of eggs observed from the other species. Sperm was demonstrated from in vitro-grown males of C. punctata and O. ostertagi Nippostrongylus brasiliensis developed to the egg-laying stage. Oeso-phagostomum radiatum, Oesophagostomum sp. (ovine), Nematodirus sp. (ovine), Haemonchus spp. (ovine and bovine) were cultivated to fourth stage. Extensive efforts at in vitro cultivation of several different isolates of Trichostrongylus axel as a monoinoculant were largely unsuccessful. The adult worms were smaller and required a longer period of development in vitro than is commonly observed in vivo. Medium Ae possessed unusual clarity considering its composition included CEE50. With the aid of a special viewing device this clarity made possible periodic observation of the worms within the culture vessel.