First Detection of DS-1-like G1P[8] Double-gene Reassortant Rotavirus Strains on The American Continent, Brazil, 2013

Abstract

Emergence of DS-1-like-G1P[8] rotavirus in Asia have been recently reported. We report for the first time the detection and the whole genome phylogenetic analysis of DS-1-like-G1P[8] strains in America. From 2013 to 2017, a total of 4226 fecal samples were screened for rotavirus by ELISA, PAGE, RT-PCR and sequencing. G1P[8] represented 3.7% (30/800) of all rotavirus-positive samples. DS-1-like-G1P[8] comprised 1.6% (13/800) detected exclusively in 2013, and Wa-like-G1P[8] comprised 2.1% (17/800) detected from 2013 to 2015. Whole genome sequencing confirmed the DS-1-like backbone I2-R2-C2-M2-A2-N2-T2-E2-H2. All genome segments of the Brazilian DS-1-like-G1P[8] strains clustered with those of Asian strains, and apart from African DS-1-like-G1P[8] strains. In addition, Brazilian DS-1-like-G1P[8] reassortants distantly clustered with DS-1-like backbone strains simultaneously circulating in the country, suggesting that the Brazilian DS-1-like-G1P[8] strains are likely imported from Asia. Two distinct NSP4 E2 genotype lineages were also identified, indicating the existence of a co-circulating pool of different DS-1-like G1P[8] strains. Surveillance systems must be developed to examine if RVA vaccines are still effective for the prevention against unusual DS-1-like-G1P[8] strains.

Figure 1

Nucleotide based phylogenetic relatedness of RVA/Human-wt/BRA/IAL-R3122/2013/G1P[8], RVA/Human-wt/BRA/IAL-R3123/2013/G1P[8], RVA/Human-wt/BRA/IAL-R3165/2013/G1P[8], and RVA/Human-wt/BRA/IAL-R3172/2013/G1P[8] RVA genes (indicated in bold and by ●) (A) NSP1, (B) NSP2, (C) NSP3, (D) NSP4, (E) NSP5/6, (F) VP1, (G) VP2, (H) VP3, (I) VP6, (J) VP7 and (K) VP4 to other selected RVA strains. Maximum likelihood trees of complete nucleotide sequences were generated with MEGA 7.0 software. Reference strains were obtained from GenBank database. Genotypes, lineages, accession number, isolates, countries and year of each strain are indicated. The scale indicates the number of divergent nucleotide residues. Percentages of bootstrap values are shown at the branch node. A subscript “A” was assigned arbitrarily to indicate the cluster obtained with Asian DS-1-like G1P[8], equine-like G3P[8] DS-1-like strains, and Brazilian DS-1-like G1P[8] strains.