Eggs were hatched over water at 28 °C for 48 h, after which the hatched preparasitic J2s (pre-J2s) were collected and surface sterilized by incubation for 10 min in sterilization solution (0.004% mercuric chloride, 0.004% sodium azide and 0.002% Triton X-100), followed by three washes with sterile distilled water.