Molecular characterization and epidemiological aspects of non-polio enteroviruses isolated from acute flaccid paralysis in Brazil: a historical series (2005–2017)

Abstract

Due to the advanced stage of polio eradication, the possible role of non-polio enteroviruses (NPEVs) associated to acute flaccid paralysis (AFP) cases has been highlighted. In this study, we described epidemiological aspects of NPEVs infections associated to AFP and explore the viral genetic diversity, information still scarce in Brazil. From 2005 to 2017, 6707 stool samples were collected in the scope of the Brazilian Poliomyelitis Surveillance Program. NPEVs were isolated in 359 samples (5.3%) and 341 (94.9%) were genotyped. About 46 different NPEV types were identified with the following detection pattern EV-B > EV-A > EV-C. The major EV-types were CVA2, CV4, EV-A71, CVB3, CVB5, E6, E7, E11, CVA13 and EV-C99, which corresponds to 51.6% of the total. Uncommon types, such as CVA12, EV-90 and CVA11, were also identified. Different E6 genogroups were observed, prevailing the GenIII, despite periods of co-circulation, and replacement of genogroups along time. CVA2 sequences were classified as genotype C and data suggested its dispersion in South-American countries. CVA13 viruses belonged to cluster B and Venezuelan viruses composed a new putative cluster. This study provides extensive information on enterovirus diversity associated with AFP, reinforcing the need of tailoring current surveillance strategies to timely monitor emergence/re-emergence of NPEVs.

High Heterogeneity of Echoviruses in Brazilian Children with Acute Gastroenteritis

“…Multiple investigations have described the molecular epidemiology of echovirus globally in both clinical and environmental samples [ 13 , 42 , 43 ] including in Brazil [ 16 , 36 ]. Nevertheless, there are limited echovirus nucleotide sequences available in the GenBank database [ 21 , 44 , 45 , 46 , 47 , 48 ], especially full-genome sequences [ 6 ].…”

“…It has been suggested that E3 exhibits a distinct epidemic pattern of circulation with regular increases every four to seven years [ 7 , 60 ]. In recent years, E3 has been identified with increased frequency in Brazil, although maintaining its minor pattern of prevalence [ 17 , 46 , 47 , 48 ]. Sequencing methods have become more accessible, and genetic characterization of EV strains is the basis for current EV genotyping [ 60 ], perhaps leading to an increased E3 identification.…”

“…The majority of E11 detection occur in infants aged <1 year [ 63 ], as observed here. E11 was detected in 6.7% of the stool samples analyzed from symptomatic acute flaccid paralysis patients in Brazil [ 48 ], and a regular distribution of its association with aseptic meningitis cases has also been reported [ 43 , 46 ], suggesting a high occurrence of this genotype in this country. Phylogenetic analysis of the VP1 gene has indicated the existence of multiple E11 lineages and/or subtypes [ 61 ].…”

“…Historically, E20 has been very rare in most surveillance system reports [7,57,58,64], including in Brazil [48]. E20 shows a tendency to recur at variable intervals [7].…”

“…Despite E29 being detected globally, epidemiological data on EV from Europe, Americas, Asia, and Africa reveal that this particular genotype exhibits low rates of frequency [6,48,56,59,[65][66][67][68], corroborating its rarity in the circulation. The reason for this particular pattern of circulation is still unclear but is frequently also observed for other echovirus strains [7,60].…”