engleski

Overview of the Rotavirus A genotypes circulating in hospitalized children in wider Zagreb and Split areas during 2020 and 2021

Rotavirus is the leading cause of severe diarrhea among young children and animals with Rotavirus A (RVA), having the greatest impact considering its prevalence and pathogenicity. The segmented rotavirus genome is enclosed within three layered capsid, with an outer layer consisting of VP4 and VP7 proteins representing the foundation for binary classification. In years 2020 and 2021 we have collected and tested 191 fecal samples mostly from hospitalized children, 92 samples originating from the wider Zagreb area, and 99 from the wider Split area. All the obtained samples have tested positive with the immunochromatographic assay in their respective hospital centers. Using multiplex semi- nested PCR, either G or P genotype was determined in 189 samples and G/P genotype combination was found in 175 samples. For the unattained and the representative strains of each genotype, Sanger sequencing of amplified VP7 and VP4 gene segments was used for corroboration. Considering our data, G genotypes circulating among children in two Croatian regions were G3 (52.4%), G9 (14.7%), G2 (3.7%), G1 (1%), G8 (1%), mixed G genotypes (23.6%) and untypeable G genotype (3.7%). The P genotypes predominantly consisted of P[8] (85.3%), followed by P[4] (2.6%), P[9] (2.1%), P[6] (1%), P[14] (1%), mixed P genotypes (2.1%) and finally untypeable P genotypes (4.7%). We also noted eight different G and P combinations, listed in the order of predominance as follows: G3P[8], G9P[8], G2P[4], G2P[8], G9P[6], G9P[9], G1P[8], G8P[14], alongside various mixed genotypes. Among eight genotype combinations, three may be considered uncommon (G2P[8], G9P[6] and G9P[9]). An animal to human interspecies transmission was evidenced with the circulation of bovine-like G8, G10 and P[14] RVA strains. G10 strains were only detected in mixed genotype group. An additional fact to accentuate is that within the G3 genotype, emerging G3 equine-like RVA strains were predominant with a 97% share over classic G3 strains. This represents an increase from a 48.5% share detected in two previous RVA seasons. The observation of the high detection rate of mixed G genotype in the present research is usually more common in developing countries. To conclude, our results state the importance of monitoring dynamic changes in the prevalence of different RVA genotypes which may serve as a basis for the eventual introduction of RVA vaccines in the national immunization program in Croatia.

Rotavirus A, hospitalized children, diarrhea, national immunization programme

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