Non-polio enteroviruses circulation in acute flaccid paralysis cases and sewage in Senegal from 2013 to 2021

Abstract

Objectives: Several factors can cause acute flaccid paralysis cases including non-polio enteroviruses. In Senegal, few studies on non-polio enteroviruses (NPEV) have been performed.

Methods: Our study assess the molecular epidemiology of non-polio enteroviruses in Senegal from 2013 to 2021 through the previously existing programs for surveillance of polioviruses.

Results: A total of 3815 stool samples and 281 sewage samples were collected. After virus isolation by cell culture, non-polio enteroviruses-positive isolates were confirmed by reverse transcriptase-quantitative polymerase chain reaction. Following this detection, the positive samples were subjected to molecular characterization. Our data showed that 15.22% and 52.66% were positive in cell culture for non-polio enteroviruses in acute flaccid paralysis surveillance and environmental surveillance, respectively. These non-polio enteroviruses-positive isolates were detected all year round but tend to unequal peaks of circulation, and the age group 0-5 years was more vulnerable to infection (84.4%). Genetic characterization revealed the circulation of enteroviruses species infecting humans (Enterovirus A - Enterovirus D): Enterovirus A (29.2%) and Enterovirus B (63.1%) isolates from both the acute flaccid paralysis surveillance and environmental surveillance while Enterovirus C (5.3%) and Enterovirus D (2.4%) were only isolated from the acute flaccid paralysis surveillance. However, the highly prevalent Enterovirus B species from the acute flaccid paralysis surveillance included echovirus 7 and echovirus 13, whereas coxsackievirus A6 was the predominant species from the environmental surveillance.

Conclusion: This first 8-year period study of NPEV in Senegal showed that NPEV represent important viral etiologies associated with acute flaccid paralysis cases and circulating in environmental surveillance in Senegal and highlighted the need to promote effective long-term strategies for monitoring of non-polio enteroviruses infections.

Keywords: Acute flaccid paralysis; Environment; Genetic diversity; Non-polio enteroviruses; Senegal.