Genetic diversity of the enteroviruses detected from cerebrospinal fluid (CSF) samples of patients with suspected aseptic meningitis in northern West Bank, Palestine in 2017

BACKGROUND: Human enterovirus genus showed a wide range of genetic diversity. OBJECTIVES: To investigate the genetic diversity of the enteroviruses isolated in 2017 in northern West Bank, Palestine. STUDY DESIGN: 249 CSF samples from aseptic meningitis cases were investigated for HEV using two RT-PCR protocols targeting the 5’ NCR and the VP1 region of the HEV genome. The phylogenetic characterization of the sequenced VP1 region of Echovirus18 (E18) and Coxsackievirus B5 (CVB5) isolated in Palestine along with 27 E18 and 27 CVB5 sequences available from the Genbank were described. RESULTS: E18 and CVB5 account for 50% and 35% of the successfully HEV types, respectively. Phylogenetic tree of E18 and CVB5 showed three main clusters, with all Palestinian isolates uniquely clustering together with those from China and from different countries, respectively. Cluster I of E18, with 13 Palestinian and 6 Chinese isolates, showed the lowest haplotype-to-sequence ratio (0.6:1), haplotype diversity (Hd), nucleotide diversity (π), and number of segregating sites (S) compared to clusters II and III. Furthermore, cluster I showed negative Tajima’s D and Fu-Li’sF tests with statistically significant departure from neutrality (P<0.01). In both E18 and CVB5 populations, high haplotype diversity, but low genetic diversity was evident. Inter-population pairwise genetic distance (Fst) and gene flow (Nm) showed that the Palestinian E18 and CVB5 clusters were highly differentiated from the other clusters. CONCLUSIONS: The study divulged close genetic relationship between Palestinian HEV strains as confirmed by population genetics and phylogenetic analyses.