The isolation of viable coccidial sporozoites

A method is described by which viable sporozoites of the sheep parasite, Eimeria arloingi , may be obtained in sterile solution and free of any extraneous vegetable matter. Faeces are washed through metal sieves and the oocysts separated by a gravity floatation technique. The oocysts are sterilized and floated free of any remaining faecal debris in a solution of sodium hypochlorite. Sporulation is induced by constant aeration in water. Excystation is effected by incubating firstly under an atmosphere of carbon dioxide and secondly in a solution of trypsin and sheep bile. I wish to thank Professor H. R. Carne for encouragement and advice, and Mr R. F. Jones for skilful technical assistance.