Genetic diversity of Coxsackievirus A21 associated with sporadic cases of acute respiratory infections in Malaysia

BACKGROUND: Coxsackievirus A21 (CVA21), a member of Enterovirus C from the Picornaviridae family, has been associated with respiratory illnesses in humans. METHODS: A molecular epidemiological investigation of CVA21 was conducted among patients presenting with acute upper respiratory illnesses in the ambulatory settings between 2012 and 2014 in Kuala Lumpur, Malaysia. RESULTS: Epidemiological surveillance of acute respiratory infections (n = 3935) showed low-level detection of CVA21 (0.08%, 1.4 cases/year) in Kuala Lumpur, with no clear seasonal distribution. Phylogenetic analysis of the new complete genomes showed close relationship with CVA21 strains from China and the United States. Spatio-temporal mapping of the VP1 gene determined 2 major clusters circulating worldwide, with inter-country lineage migration and strain replacement occurring over time. CONCLUSIONS: The study highlights the emerging role of CVA21 in causing sporadic acute respiratory outbreaks. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12879-021-06148-x.