Freeze-drying of Aegyptianella pullorum.

Heparinized whole blood, parasitized with Aegyptianella pullorum, was collected from 2 fowls. Buffered lactose peptone (BLP) was added v/v as a stabilizer and the mixture lyophilized in 2 ml aliquots after rapid or slow freezing. At different stages during the freeze-drying process, as well as after lyophilization and reconstitution with 1.8 ml of sterile water, samples were taken and injected into pullets. Infectivity was maintained throughout. However, the prepatent period was lengthened after freezing and particularly after lyophilization when there was some loss of viability.