SUMMARYThe immune evasion gene family of malaria parasites encodes variant surface proteins that are expressed at the surface of infected erythrocytes and help the parasite in evading the host immune response by means of antigenic variation. The identification ofPlasmodium vivax virorthologous immune evasion gene family from primate malaria parasites would provide new insight into the evolution of virulence and pathogenesis. Threevirsubfamilies viz.vir-B, vir-Dandvir-Gwere successfully PCR amplified from primate malaria parasites, cloned and sequenced. DNA sequence analysis confirmed orthologues ofvir-Dsubfamily inPlasmodium cynomolgi, Plasmodium simium, Plasmodium simiovaleandPlasmodium fieldi. The identifiedvir-Dorthologues are 1–9 distinct members of the immune evasion gene family which have 68–83% sequence identity withvir-Dand 71·2–98·5% sequence identity within the members identified from primate malaria parasites. The absence of othervirsubfamilies among primate malaria parasites reflects the limitations in the experimental approach. This study clearly identified the presence ofvir-Dlike sequences in four species ofPlasmodiuminfecting primates that would be useful in understanding the evolution of virulence in malaria parasites.
