Abstract: An antigen which produces immunity against homologous or heterologous challenge with babesia of cattle. The antigen is immunoreactive with a monoclonal antibody or polyclonal antisera recognising a protein located on the surface of babesia-infected erythrocytes and within a spherical or mitochondrion like organelle. The antigen can be prepared by (i) preparing nucleic acids from babesia infected erythrocytes depleted of leucocytes; (ii) forming a cDNA or genomic library from nucleic acids obtained in step (i); (iii) screening said library formed in step (ii) with a suitable probe to identify clones of interest; and thus providing DNA inserts for an expression vector which may be used to transform an appropriate host; (iv) obtaining a recombinant polypeptide from said transformed hosts which is protective against babesiosis.

Abstract: This invention relates to a method of preparation of a babesiosis vaccine which involves treating a suspension of Babesia infected erythrocytes. The erythrocytes are disintegrated, separated into soluble and insoluble fractions and subsequently fibrinogen and contaminated Babesia antigen is removed from the soluble fraction. The residual soluble fraction is then combined with an adjuvant to form the babesiosis vaccine. The invention also includes within its scope a vaccine derived from the abovementioned method and a method of administration of the vaccine to cattle.