Molecular Epidemiology of Enterovirus A71 in Surveillance of Acute Flaccid Paralysis Cases in Senegal, 2013–2020

Abstract

Enterovirus A71 (EV-A71) is a non-polio enterovirus that currently represents a major public health concern worldwide. In Africa, only sporadic cases have been reported. Acute flaccid paralysis and environmental surveillance programs have been widely used as strategies for documenting the circulation of polio and non-polio enteroviruses. To date, little is known about the molecular epidemiology of enterovirus A71 in Africa where resources and diagnostic capacities are limited. To fill this gap in Senegal, a total of 521 non-polio enterovirus isolates collected from both acute flaccid paralysis (AFP) and environmental surveillance (ES) programs between 2013 and 2020 were screened for enterovirus A71 using real-time RT-PCR. Positive isolates were sequenced, and genomic data were analyzed using phylogeny. An overall rate of 1.72% (9/521) of the analyzed isolates tested positive for enterovirus A71. All positive isolates originated from the acute flaccid paralysis cases, and 44.4% (4/9) of them were isolated in 2016. The nine newly characterized sequences obtained in our study included eight complete polyprotein sequences and one partial sequence of the VP1 gene, all belonging to the C genogroup. Seven out of the eight complete polyprotein sequences belonged to the C2 subgenotype, while one of them grouped with previous sequences from the C1 subgenotype. The partial VP1 sequence belonged to the C1 subgenotype. Our data provide not only new insights into the recent molecular epidemiology of enterovirus A71 in Senegal but also point to the crucial need to set up specific surveillance programs targeting non-polio enteroviruses at country or regional levels in Africa for rapid identification emerging or re-emerging enteroviruses and better characterization of public health concerns causing acute flaccid paralysis in children such as enterovirus A71. To estimate the real distribution of EV-A71 in Africa, more sero-epidemiological studies should be promoted, particularly in countries where the virus has already been reported.

Screening of a new candidate coxsackievirus B1 vaccine strain based on its biological characteristics

“…At present, most mouse models are primarily used to evaluate the protective effects of CVB1 vaccines against virus-induced T1DM. In previous research, the RD cell-adapted strain 204 showed strong tropism to the pancreas, but no damage to the heart, brain, liver, limb muscle, and kidney was observed, and in moribund mice, a positive signal was only observed in the heart and spinal cord (Ndiaye et al, 2022 ). In the present study, histopathology and IHC analyses and tissue viral RNA detection indicated that the KM7-X29 strain had stronger tropism to the pancreas, brain, and liver.…”

“…The previous study also found differences in cross-neutralization between the 10 EV-A71 sub-genotypes tested; a C4 genotype EV-A71-based vaccine elicited a powerful cross-neutralization response against other EV-A71 C4 genotypes, and the cross-neutralization of genotype A (EV-A71 prototype strain) was the least efficient. As EV-A71, which included one serotype, five genotypes, and ten sub-genotypes (McMinn, 2012 ; Ndiaye et al, 2022 ), CVB1 has one serotype and eight genotypes, although the GII genotype is the most common among them in China. In addition, we found that the antiserum against our inactivated CVB1 vaccine could not efficiently neutralize the CVB1 prototype strain Conn-5, which requires further research.…”

Non-Polio Enterovirus Surveillance in the Ural Federal District and Western Siberia, 2022: Is There a Need for a Vaccine?

“…We reported only eight cases of EVA71 in 2022; all were mild and without neurologic manifestations. In a Senegalese study by Ndaye et al in 2022, a low number of isolates tested positive for EVA71 (9 out of 521 NPEV isolates) [31]. While a recent study from South Vietnam reported the predominance of EVA71 as the etiological agent of HFMD, AFP and enteroviral meningitis [32].…”