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Surveillance for acute flaccid paralysis syndrome (AFP) in children under 15 is the backbone of the Global Polio Eradication Initiative. Laboratory examination of stool samples from AFP cases allows the detection of, along with polioviruses, a variety of non-polio enteroviruses (NPEV). The etiological significance of these viruses in the occurrence of AFP cases has been definitively established only for enteroviruses A71 and D68. Enterovirus Coxsackie A2 (CVA2) is most often associated with vesicular pharyngitis and hand, foot and mouth disease. Among 7280 AFP cases registered in Russia over 20 years (2001–2020), CVA2 was isolated only from five cases. However, these included three children aged 3 to 4 years, without overt immune deficiency, immunized with 4–5 doses of poliovirus vaccine in accordance with the National Vaccination Schedule. The disease resulted in persistent residual paralysis. Clinical and laboratory data corresponded to poliomyelitis developing during poliovirus infection. These findings are compatible with CVA2 being the cause of AFP. Molecular analysis of CVA2 from these patients and a number of AFP cases in other countries did not reveal association with a specific phylogenetic group, suggesting that virus genetics is unlikely to explain the pathogenic profile. The overall results highlight the value of AFP surveillance not just for polio control but for studies of uncommon AFP agents.

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Aim: Characteristics of enterovirus infection morbidity and study of peculiarities of enterovirus circulation on some territories of Russia in 2017. Materials and methods: We investigated more than 5000 samples from the patients with enterovirus infection. The isolation and identification of enteroviruses were conducted by virological method and by partial sequencing of the genome region VP1. Phylogenic trees were constructed according to the method of Bayesian Monte Carlo Markov Chain. Results: Epidemic process and clinical picture of enterovirus infection were not the same on different territories. Peculiarities of the circulation of different types of enteroviruses on the territories were also different. In Saratov region 65% of cases were represented by enterovirus meningitis. In Murmansk region and in the Komi Republic enterovirus infection with exanthema prevailed, 95% and 60% correspondingly. In Saratov region enterovirus ECHO18 was the etiological agent of enterovirus meningitis. In Murmansk region and in the Komi Republic the cases were connected mainly with Coxsackieviruses A6. The strains of enterovirus ECHO18 were distributed to three clusters. The strains which provoked enterovirus meningitis in Saratov region belonged to cluster 3, they were formed separately from other strains of this enterovirus type and differed from the stains of ECHO18 which circulated in the North-West of Russia. The strains of Coxsackieviruses A6 identified in the North-West of Russia belonged to three sub-genotypes 5, 6, 8 of pandemic genotype of CoxsackievirusesA6. The majority of the strains belonged to sub-genotypes 6 and 8 which in 2017 dominated in the structure of Coxsackieviruses A6 in the North-West of Russia and in Russia. Conclusion: Epidemic peaks of enterovirus infection represented by different clinical forms of the disease were provoked by different types of enteroviruses. Enterovirus ECHO18 was the etiological agent of enterovirus meningitis. The main etiological factors of enterovirus infection with exanthema were Coxsackieviruses A6 of different sub-genotypes.