Morphological studies of Babesia divergens during continuous transfer in Meriones unguiculatus

: A strain of Babesia divergens was propagated by inoculation of 1.5 x 10(7) parasitized erythrocytes in 30 passages under same conditions on altogether 150 jirds. The developmental stages of Babesia divergens revealed pleomorphism in the erythrocytes of the jird. Single parasites were observed as being pyriform, globular, budding, ring-like or amoebid. The shape of dividing parasites varied between the spherical and the pyriform. The stages in the erythrocytes were localized predominantly intermedia. The reduction of the number of dividing forms and the increase of single forms occurred with increasing numbers of passages. Length and breadth of double pyriforms increased by approximately 20%.