West Nile virus (WNV) is a small, enveloped, mosquito transmitted virus with a positive sense, 11 kb RNA genome. It was first isolated in 1937 from a woman with an undiagnosed febrile illness in the West Nile district of Uganda, WNV is currently the most widely distributed arbovirus in the world, occurring in all continents except Antarctica, there are no clinically approved vaccines or antiviral drugs, thus, the aim of this study is to analyze envelope glycoprotein variants using in silico approaches looking for conservancy, which is further studied to predict all potential epitopes that can be used after in vitro and in vivo confirmation as a therapeutic peptide vaccine. Total of 149envelope glycoprotein variants retrieved from NCBI database were introduced to IEDB conservancy tool, to select the highly conserved regions for epitopes prediction. By means of IEDB analysis resource B and T cell epitopes were predicted and population coverage was calculated. Three epitopes were proposed for international therapeutic peptide vaccine for B cell (DLSTKAACPTMGEAHNDKRADPAFV, YGEVTVDCEPRSGIDTN and PVEFSSNTVKL). Regarding T cell, RSYCYLATV epitope was highly recommended as therapeutic peptide vaccine to interact with MHC class I along with five other epitopes that showed good population coverage against whole world population. Two epitopes showed high affinity to interact with MHC class II alleles ( IKYEVAIFV and WFMDLNLPW ). Epitopes defined by methods such as the one described here are likely to contribute substantially to the development of new in vivo and in vitro research ,diagnostic and vaccines for WNV and other emerging infectious diseases.