Molecular characterization of VP6 and NSP4 genes of unusual G and P
Rotavirus group A isolated from children with acute gastroenteritis
Abstract
Group A Rotavirus (RVA), which causes acute gastroenteritis (AGE) in
children worldwide, is categorized mainly based on VP7 (genotype G) and
VP4 (genotype P) genes. Genotypes that circulate at <1% are
considered unusual. Important genes are also VP6 (genotype I) and NSP4
(genotype E). VP6 establishes the group and affects immunogenicity,
while NSP4, as enterotoxin, is responsible for the clinical symptoms.
Aim of this study was to genotype and molecularly characterize the VP6
and NSP4 genes of unusual RVA. Unusual RVA strains isolated from fecal
samples of children ≤16 years with AGE, were genotyped in VP6 and NSP4
genes with Sanger sequencing. Phylogenetics was performed using the MEGA
11 program. In a 15-year period (2007-2021), 54.8% (34/62) of unusual
RVA were successfully I and E genotyped. Three different I and E
genotypes were identified; I2 (73.5%, 25/34) and E2 (35.3%, 12/34)
were the commonest. E3 genotype was detected from 2017 onwards. The
uncommon combination of I2-E3 was found in 26.5% (9/34) of the strains
and G3-P[9]-I2-E3 was the most frequent G-P-I-E combination (20.6%,
7/34). Statistical analysis showed that children infected with E2
strains had a higher relative frequency of dehydration (50%) compared
to those with the E3 genotype ( p=0.019). Multiple substitutions
were detected in both genes, but their functional effect remains
unknown. The results of this study highlight the genetic diversity of
RVA strains. Continuous surveillance of the RVA based on the whole
genome will provide a better knowledge of its evolution.