Cryopreservation of sheathed third-stage larvae of Gaigeria pachyscelis (Sandveld hookworm).

A technique for the cryopreservation of third stage larvae of Gaigeria pachyscelis is described. It consists of incubating sheathed third-stage larvae in 80% (v/v) ethylene glycol as a cryoprotectant for 30 s at 0 degrees C, prior to transfer into liquid nitrogen. The survival rate, as assessed by motility, was 37.6% after 30 d cryopreservation. A sheep infected percutaneously with 700 live cryopreserved third-stage larvae, harboured 41 adult worms (infectivity rate: 5.8%) when necropsied 78 d later.