First Report of Hand, Foot, and Mouth Disease (HFMD) Outbreak in the West Bank, Palestine: Molecular Characterization of Coxsackievirus A16 (CV-A16)

Introduction: Hand, foot, and mouth disease (HFMD) is a mild self-limited childhood infectious disease caused by a variety of enteroviruses (EVs).Aim: To investigate the molecular epidemiology of EVs associated with HFMD and their clinical presentation during the HFMD outbreak that occurred in the Jenin district, Palestine, from May to August 2024.Materials and Methods: Forty-four (44) throat and vesicular swabs were tested for enteroviral infections using two RT-PCR assays targeting both the 5 ' NTR and the VP1-2A regions of the enteroviral genome for the diagnosis and genotyping. Patients' demographic data and clinical history were used to create an epidemiological curve. EpiInfo free software was used to draw a cluster mapping. MEGA-X was used to construct a maximum likelihood (ML) tree. PopArt 1.7 software was used to construct neighbor-joining network.Results: The mean age of the study sample was 2.08 (0.25-12 years) with 95% (42/44) under five years old. The male/female ratio was 0.9. All cases presented with typical HFMD signs and symptoms with variable sites of signs. Of the 44 samples, 36 yield positive RT-PCR targeting the 5 ' NTR. Seven randomly selected positive RT-PCR-5 ' NTR samples were sequenced using Sanger sequencing for genotyping. It was shown that all were CV-A16 sub-genogroup B1c. Phylogenetic analysis of VP1-2A region sequences showed that all Palestinian CV-A16 isolates form a pure haplogroup of CV-A16 sub-genotype B1c. Furthermore, although haplotype network analysis showed high variation between the viral sequences, the haplotype analysis supported the ML phylogenetic tree in having them all in one haplogroup.Conclusion: CV-A16, sub-genotype B1c was the virus responsible for the HFMD outbreak in the Jenin district of Palestine in the summer of 2024. Phylogenetic and haplotype analysis showed that CV-A16 strains cluster closely with each other and very close to an Indian isolate (OR437338.1), indicating the monomorphic nature of this strain with low genetic variation and the probability of virus importation.