Development of larvae of Ascaris suum from the third to the fourth stage in a chemically defined medium

Third stage larvae of Ascaris suum, recovered from the lungs of rabbits 7 days after oral infection with eggs, were cultured to the fourth larval stage in chemically defined, low molecular weight medium. The medium consisted of tissue culture medium 199, supplemented with glucose and glycyl-hystidyl-lysine and gassed with a mixture of N₂-CO₂-O₂ (90:5:5). Growth and development in this medium were similar to that in media supplemented with whole serum or with a serum dialysate.