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Abstract. Enteroviruses are small RNA viruses, which are ubiquitous and commonly cause outbreaks with various clinical manifestations. In 2006, the Program on enterovirus surveillance was approved in the Russian Federation. Over the last years, molecular-biological and bioinformatics methods for enterovirus epidemiology studies have been developed both in Russia and worldwide. Currently, identification of enteroviruses is carried out by analyzing nucleotide sequence of the full-length VP1 genome region (ca. 900 nt). Routinely, it is sufficient to obtain a partial VP1 genome region sequence (ca. 300 bp) for enteroviruse verification in most cases; however, a more stringent type criterion of 80% sequence identity should be used compared to the 75% sequence identity cut-off for the complete VP1 genome region. Further sequence analysis may be performed by using Bayesian phylogenetic methods, which allow using molecular clock to trace outbreak emergence. Enteroviruses accumulate about 0.5–1% nucleotide substitutions per year. Therefore, a short genome fragment may be used to analyze virus phylodynamics at the level of international transfers and circulating virus variants. On a shorter timescale, a full-length VP1 genome region or a complete genome sequence are preferred for investigating molecular epidemiology, because a short sequence allows to reliably distinguish not more than 1–2 transmission events per year. Thus, determining enterovirus sequences for full-length VP1 genome region or full-genome sequence is preferred for examining viral outbreaks. It is increasingly apparent that analyzing available enterovirus nucleotide sequences reveals limitations related to uneven surveillance efficacy in various countries and short length of genome fragment measured in routine control. As a result, a proper global-scale analysis of enterovirus molecular epidemiology remains problematic. Over the last 20 years, the number of available enterovirus nucleotide sequences increased by hundred times, but understanding emergence of enterovirus infection outbreaks remains limited. Further development of enterovirus surveillance would require new methods for sewage monitoring, affordable high-throughput sequencing and harmonization of global surveillance systems.

Abstract. The analysis of epidemic process and definition of the etiology of the seasonal increase of serosal meningitis incidence in the Novgorod oblast in September-November, 2008 has been carried out. It was shown that in the specified period 73 persons had enteroviral meningitis. The proportion of children under 17 years old in the group of patients was 89.9%. The etiological agents of disease (enteroviruses ECHO 6 и ECHO 30) were detected by the virological and molecular-biological methods. It was established that two genetic variants of ECHO 6 and one variant of ECHO 30 co-circulated in the Novgorod oblast. The last virus variant was closely related to the strain isolated from enteroviral meningitis patients in Nizhniy Novgorod in 2007. The obtained data support the idea about necessity of systematic epidemiological and virological surveillance on enteroviral infection to get new information about circulation of non-poliomyelitis enteroviruses in the population and to define peculiarities of epidemic process development.

Long-term manifestations of epidemiological process of enterovirus infection in the Jewish Autonomous Region were similar to those in the Khabarovsk Territory, though with a lower intensity. After establishment of emergency situation regime, in view of the rainfall flooding in 2013, enterovirus morbidity rate had been increasing within three weeks duration, then started to fall rapidly. Clustered cases of enterovirus infection were not registered. Viral serous meningitis ratio was insignificant as minor forms of the disease prevailed; coxsackie virus A-9 and echovirus-6 dominated. During the flood period isolated from samples of patients with minor forms of enteroviral disease were three enterovirus strains, type 71, sub-genotype C4a, possessing a high degree of genetic similarity to the Chinese ones, 2010-2011. All in all impact of the natural disaster on the epidemiological situation on enteroviral infection in the Jewish Autonomous Region turned to be insignificant.