Surveillance of enterovirus infection and genotypes/subgenotypes of enteroviruses in Dak Lak, Vietnam in 2022-2024.

OBJECTIVES

Human enteroviruses (EVs) are associated with a broad spectrum of diseases, including hand, foot, and mouth disease. This study aimed to understand the epidemiology and genotypes/subgenotypes of EVs circulated in Dak Lak, Vietnam between 2022 and 2024.

METHODS

Samples were collected from patients admitted to the inpatient and outpatient departments from 2022 to 2024 in Dak Lak of Vietnam. EVs were identified in all samples through real-time reverse-transcription polymerase chain reaction using a commercially available kit.

RESULTS

EVs were detected in 96 samples in the period from 2022-2024 in total of 167 suspected samples; the EV-positive rate was 57.5%. The highest positivity rate for EVs was observed in children aged <5 years, reaching 96.8%, while the rates of EV infections showed no significant differences between genders. The monthly positivity rate for EV infection ranged from 0% to 84.6%, with a peak in September. The most frequently observed EVs were EV A71 (28.1%), Coxsackievirus A6 (28.1%), followed by Coxsackievirus A16 (16.7%) and Coxsackievirus A10 (10.4%), while the proportion of unidentified EV serotypes were 10.4%. The phylogenetic analysis of the VP1 gene of EV A71 strains revealed that two genotypes, B5 (93.7%) and C4 (6.3%), were found and all were closely related to variants causing epidemics of hand, foot, and mouth disease in southern Vietnam that circulated in 2023. Meanwhile, all CVA6, CVA16, and CVA10 strains belonged to D3, B1a, and C3 subgenotypes, respectively.

CONCLUSION

EV infection is highly prevalent among young children aged <5 years in Dak Lak. Further monitoring through techniques capable of subtyping all EVs is necessary to enhance the observation of these infections and their causes.