Epidemiology and Molecular Characterization of Chikungunya Virus from Human Cases in North India, 2016

Chikungunya virus (CHIKV), an arthropod-borne Alphavirus is responsible for chikungunya disease. Arthralgia and arthritis are the major symptom. Some patients recover early while others for a very long time. This study provides, epidemiology and molecular characterization of three whole-genome sequences of CHIKV and assessed phylogenetic analysis, physiological properties, antigenicity, and B-cell epitope prediction by in silico. We report the clinical epidemiology of 325 suspected patients. Of these, 118 (36.30%) were confirmed CHIKV positive by either PCR or ELISA. Clinical analysis showed joint pain, joint swelling and headache were frequent and significant features. Phylogenie analysis showed the currently circulating strain is in close clustring to Africa, Uganda, and Singapore CHIKV strains. Molecular characterization by WGS was done. Thirty eight amino acid changes in the nonstructural proteins were found with respect to the S27 (ECSA) strain. Of these five located in nsP2. Similarly, 34 amino acid changes in structural proteins were observed. The major change was notice; in E3 protein hydropathicity -0.281 to -0.362, in E2 isoelectric point (pI) 8.24 to 8.37, instability index 66.08 to 71.062, aliphatic index varied from 74.69 to 68.59 and E3 75.79 to 70.05. In nsP1 protein pI varies from 6.62 to 8.04, while no other change was observed in structural and nonstructural protein. The linear B-cell epitopes, position, and number varied with the mutation. The molecular characterizations of WGS demonstrate the observation of protein, antigenicity with respect to the mutation.