Enterovirus 71-Associated Infection in South Vietnam: Vaccination Is a Real Solution.

Hand-foot-and-mouth disease (HFMD) is the most common enteroviral infection in South-East Asia. When evaluating the role of enterovirus 71 (EVA71) as an etiological agent of infectious disease in South Vietnam, we revealed a high proportion of EVA71 among identified species A enteroviruses found in 3542 samples from HFMD cases; 125 samples from cases of enteroviral meningitis; and 130 samples from acute flaccid paralysis (AFP) cases. These represent 50%, 54.8%, and 51.5%, respectively. According to molecular analysis, 90% of EVA71 were attributed to genotype C4 and 10% were attributed to genotype B5. The predominance of EVA71 circulation among the population proves the need to strengthen surveillance (with monitoring of enterovirus circulation for facilitation of HFMD outbreak prediction) and to increase the effectiveness of preventative measures by the implementation of vaccination against EVA71-associated infections. A phase III trial of a Taiwanese vaccine (EV71vac) in Taiwan and South Vietnam showed its safety, tolerability, and efficacy in children aged 2-71 months. This B4 genotype-based vaccine, which features cross-protection against B5 and C4 genotypes, and other existing EV71 vaccines can serve as a good approach to solving the HFMD problem, which is so important for Vietnam.

Cases of Acute Flaccid Paralysis Associated with Coxsackievirus A2: Findings of a 20-Year Surveillance in the Russian Federation.

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.

Increasing detection of rotavirus G2P[4] strains in Nizhny Novgorod, Russia, between 2016 and 2019.

Rotavirus infection is one of the leading causes of acute gastroenteritis in children in their first years of life. We studied the genotypic diversity of rotavirus A (RVA) strains in Nizhny Novgorod, Russia, during the period 2016-19. In total, 4714 samples of faeces from children admitted to the Nizhny Novgorod Hospital for Infectious Diseases with acute gastroenteritis were examined. The share of rotavirus-positive samples was 31.5% in 2016-17. It decreased to 21.6% in 2018-19. In Nizhny Novgorod, all six global types of RVA were detected (G1P[8], G2P[4], G3P[8], G4P[8], G9P[8] and G12P[8]), as well as sporadic samples with genotypes G9P[4], G3P[9], G9P[9], G8P[8], G2P[8], G4P[4], G3P[9]. The fraction of strains with genotype G2P[4] gradually increased from 5.9% in 2016-17 to 39.1% in 2018-19. Simultaneously, the proportion of G9P[8] strains decreased from 63.2% to 27.7% in the same period. Phylogenetic analysis showed that rotaviruses with the G2P[4] genotype carried ubiquitous alleles of the VP7 and VP4 genes during the period of their prevalence: G2-IVa-1 and G2-IVa-3; P[4]-IVa and P[4]-IVb. As rotavirus vaccination is not widely used in the region because it is not included in the national vaccination calendar in Russia so far, the increase in the number of G2P[4] RVA is likely due to natural strain fluctuations.

Genotype constellations of the rotavirus A strains circulating in Nizhny Novgorod, Russia, 2017-2018.

Currently, the full-genome-based classification is widely used to investigate rotavirus A (RVA) strains found in different countries around the world. However, the information on the full genotypes of rotaviruses circulating in Russia is limited. Using partial sequencing, this study determined the full genotype constellations of 15 RVA strains in total commonly detected in Nizhny Novgorod (European part of Russia) in 2017-2018, three from each of the following genotypes G1P[8], G4P[8], and G9P[8] and six from G2P[4]. There were two intergenogroup mono-reassortants possessing an identical genotype constellation of G4-P[8]-I1-R1-C1-M1-A1-N1-T1-E2-H1 with the DS-1-like NSP4 gene of probably local origin. A variety of subgenotype lineages and their combinations of Wa-like rotaviruses and genetic heterogeneity among G9P[8] and G1P[8] strains were shown on the basis of phylogenetic analysis of each gene. Moreover, two distinct co-circulating variants that differed in all 11 genome segments were found among DS-1-like rotaviruses.

Phylodynamics of G4P[8] and G2P[4] strains of rotavirus A isolated in Russia in 2017 based on full-genome analyses.

Rotavirus A is a dynamically evolving pathogen causing acute gastroenteritis in children during the first years of life. In the present study, we conducted a phylodynamic analysis based on the complete sequences of 11 segments of rotaviruses with the G4P[8] and G2P[4] genotypes isolated in Russia in 2017. Since rotavirus has a segmented genome, our analysis was performed using the Bayesian approach based on separate samples of nucleotide sequences for each gene of the strains studied. For the strain with the genotype G4P[8], the most likely geographical locations of the nearest common ancestor were Russia (VP7, VP4, VP6), China (VP1), Thailand (VP3), Belgium (NSP1), Hungary (VP2, NSP2, NSP3), Italy (NSP4) and Japan (NSP5). For the strain with the G2P[4] genotype, India (VP7, VP4, VP6, NSP1, NSP4), Malawi (VP2, NSP2, NSP3), Australia (VP1), Italy (NSP5) and Bangladesh (VP3). The closest common ancestor of the strain with the genotype G4P[8] circulated in 2001-2012, depending on the gene being analyzed. For the strain with the G2P[4] genotype, the closest common ancestor dates from 2006 to 2013.